Digital Collections > USF Electronic Theses and Dissertations > The influence of valenced images on perceptual learning\nABSTRACT: This study aimed to determine whether the rate of perceptual learning in a vernier discrimination task could be influenced by affective images. Forty-eight (30 Female, 18 Male) subjects were instructed to indicate the direction of an offset over 620 trials. Subjects were primed with either negative, positive or neutral photographs before making the discrimination on all test trials. Feedback regarding offset performance was provided on each trial. Despite initial pilot data indicating that subjects primed with negative, arousing images improved performance over those primed with either neutral or positive images, there was ultimately no reliable advantage for any of the affective prime conditions.\nby Noah Sulman.\n001992345 ( ALEPH )\n316062304 ( OCLC )\nE14-SFE0002381 ( USFLDC DOI )\ne14.2381 ( USFLDC Handle )\ncontrolfield tag 001 001992345\nsubfield code a E14-SFE0002381\nAdvisor: Thomas Sanocki, Ph.D.\nT he I nf l ue nc e of V a l e nc e d I m a ge s on P e r c e pt ua l L e a r ni ng by N oa h S ul m a n A t he s i s pr e pa r e d i n pa r t i a l f u l f i l l m e nt of t he r e qui r e m e nt s f or t he de g r e e of M a s t e r of A r t s D e pa r t m e nt of P s yc hol ogy C ol l e ge of A r t s a nd S c i e nc e s U ni ve r s i t y of S ou t h F l o r i da M a j or P r of e s s or : T hom a s S a noc ki P h. D C ynt hi a C i m i no, P h D K e n M a l m be r g, P h D D ougl a s N e l s on, P h. D D a t e of A ppr ova l : 4/ 1/ 2008 K e yw or ds : vi s ua l de ve l opm e nt a f f e c t i ve s t i m ul i a t t e nt i on, e m ot i on r e i nf or c e m e nt C opyr i ght 2008 N oa h S ul m a n\nA c know l e dge m e nt s I w oul d l i ke t o t ha nk T ho m a s S a noc ki C ynt hi a C i m i no, K e n M a l m be r g a nd D ougl a s N e l s on f or t he i r i nva l ua bl e gui da nc e a nd s ugge s t i ons I w oul d a l s o l i ke t o t ha nk H e a t he r S ul m a n f or a l l o f he r l ove a nd s uppor t L a s t l y, no ne of t hi s w oul d be pos s i bl e w i t hout t he c ont r i but i ons of m a ny unde r gr a dua t e r e s e a r c h a s s i s t a nt s a nd pa r t i c i pa nt s\ni T a bl e of C ont e nt s L i s t of F i gur e s i i A bs t r a c t i i i C ha pt e r O ne 1 P e r c e pt ua l L e a r ni ng 1 P e r c e pt ua l L e a r ni ng M e c ha ni s m s 4 E m ot i on a nd A t t e nt i on 6 A t t e nt i on a nd P e r c e pt ua l L e a r ni ng 18 R e ve r s e H i e r a r c hy T he or y 18 P e r c e pt ua l T e m pl a t e M ode l 20 C ondi t i oni ng M ode l 21 V a l e nc e d S t i m ul i a nd P e r c e pt ua l L e a r ni ng 25 C ha pt e r T w o 27 P i l ot E xpe r i m e nt 1 27 P i l ot E xpe r i m e nt 2 31 C ha pt e r T hr e e 34 M e t hod 34 R e s ul t s 35 C ha pt e r F our 37 D i s c us s i on 37 R e f e r e nc e s 40\ni i L i s t of F i gur e s F i gur e 1 V e r ni e r s t i m ul us f r om pi l o t e xpe r i m e nt 1 45 F i gur e 2 S t i m ul us s e que nc e dur i ng c a l i br a t i on s t a ge 46 F i gur e 3 S t i m ul us s e que nc e dur i ng t e s t s t a ge 47 F i gur e 4 M i s s e d f i xa t i ons i n pi l ot e xpe r i m e nt 1 48 F i gur e 5 R a t e of l e a r ni ng i n pi l ot e x pe r i m e nt 1 49 F i gur e 6 M i s s e d f i xa t i ons i n pi l ot e xpe r i m e nt 2 50 F i gur e 7 N or m a l i z e d l e a r ni ng i n pi l ot e xpe r i m e nt 2 51 F i gur e 8 M i s s e d f i xa t i ons i n pi l ot e xpe r i m e nt 2 52 F i gur e 9 E xpe r i m e nt r e s ul t s 53 F i gur e 10 M i s s e d f i xa t i ons i n e xpe r i m e nt 54 F i gur e 11 O f f s e t pe r f or m a nc e i n e xpe r i m e nt 55\ni i i T he I nf l ue nc e of V a l e nc e d I m a ge s on P e r c e pt ua l L e a r ni ng N oa h S ul m a n A B S T R A C T T hi s s t udy a i m e d t o de t e r m i ne w he t he r t he r a t e of pe r c e pt ua l l e a r ni ng i n a ve r ni e r di s c r i m i na t i on t a s k c oul d be i n f l ue nc e d by a f f e c t i ve i m a ge s F or t y e i ght ( 30 F e m a l e 18 M a l e ) s ubj e c t s w e r e i ns t r uc t e d t o i nd i c a t e t he di r e c t i on o f a n of f s e t ove r 620 t r i a l s S ubj e c t s w e r e pr i m e d w i t h e i t he r ne ga t i ve pos i t i ve or ne ut r a l phot ogr a phs be f o r e m a ki ng t he di s c r i m i na t i on on a l l t e s t t r i a l s F e e dba c k r e ga r di ng of f s e t pe r f o r m a nc e w a s pr ovi de d on e a c h t r i a l D e s pi t e i ni t i a l pi l ot da t a i n di c a t i ng t ha t s ubj e c t s pr i m e d w i t h ne ga t i ve a r ous i ng i m a ge s i m pr ove d pe r f o r m a nc e ove r t hos e pr i m e d w i t h e i t he r ne ut r a l or pos i t i ve i m a ge s t he r e w a s ul t i m a t e l y no r e l i a bl e a dv a nt a ge f or a ny of t he a f f e c t i ve pr i m e c ondi t i ons\n1 C ha pt e r O ne I nt r oduc t i on P e r c e pt ual L e ar ni ng A c om pl e t e a c c ount of t he r ol e of e xpe r i e nc e i n pe r c e pt i on i s e s s e nt i a l t o our unde r s t a ndi ng of pe r c e pt i on m or e ge ne r a l l y M a ny r e s e a r c h t e c hni que s us e d t o e va l ua t e t he c ont r i but i ons of pe r c e pt ua l e xpe r i e nc e e m pl oy pe r c e pt ua l l e a r ni ng pa r a di gm s P e r c e pt ua l l e a r ni ng ha s be e n de f i ne d a s : [ a ] ny r e l a t i ve l y pe r m a ne nt a nd c ons i s t e nt c ha nge i n t he pe r c e pt i on of a s t i m ul us a r r a y f ol l ow i ng pr a c t i c e or e xpe r i e nc e w i t h t hi s a r r a y. ( G i bs on, 1969 p 49) T he e s s e nt i a l c ha r a c t e r i s t i c of pe r c e pt ua l l e a r ni ng i s t ha t i t i nvol ve s dur a bl e l e a r ni ng i n r e s pons e t o a n unc h a ng e d s t i m ul us ( E ps t e i n, 1967) U ns t a bl e pe r c e pt s a da pt a t i ons s hi f t s i n oc ul a r do m i na nc e a nd s i m i l a r phe nom e na a r e e xc l ude d be c a us e of t he i r e phe m e r a l e f f e c t s W i t hi n E ps t e i n s ( 1967 ) c onc e pt ua l i z a t i on o f t he f i e l d, pe r c e pt ua l l e a r ni ng ( P L ) i nc l ude s a va r i e ga t e d s e t of e xpe r i m e nt a l pa r a di gm s O f t hos e e xpe r i m e nt s t ha t do not f i ne l y c ont r ol e xpe r i e nc e t he r e a r e t hos e t ha t e va l ua t e t he c ont r i but i ons o f l ong t e r m pr e e xpe r i m e nt a l e xpe r i e nc e t o pe r c e pt ua l pe r f or m a nc e A n e xa m pl e of t h i s va r i e t y o f i nve s t i ga t i on m i ght i nvol ve s ubj e c t s m a t c hi ng t he a ppa r e nt s i z e of a pe nny i n a n a ppa r a t us t o a hubc a p a t s om e d i s t a nc e A not he r t ype of P L e xpe r i m e nt e nt a i l s obs e r va t i ons of pe r c e pt ua l pe r f o r m a nc e w hi l e s ubj e c t s a r e pr e s e nt e d w i t h c onf l i c t i ng l e a r ne d c ue s s uc h a s i ns t r uc t i ng s ubj e c t s t o e s t i m a t e a di s t a nc e i n a s t i m ul us a r r a y c ont a i ni ng c ont r a di c t or y de pt h i nf o r m a t i on. R e s e a r c he r s ha ve a l s o t e s t e d t he i nf l ue nc e o f\n2 gl oba l c ha nge s t o t he vi s ua l s ys t e m e pi t om i z e d i n t he c l a s s i c s t udi e s of K ohl e r ( 1962 ) i n w hi c h s ubj e c t s w or e pr i s m s t ha t i nve r t e d t he i r vi e w a s t he y na vi ga t e d r e a l w o r l d e nvi r onm e nt s D e ve l opm e nt a l s t udi e s t he l a s t va r i e t y of P L s t udy t ha t i nvol ve s t he us e of unc ont r ol l e d pr e e xpe r i m e nt a l e xpe r i e nc e s e e k t o m e a s ur e t he i nf l ue nc e of e xpe r i e nc e a s i t a c c r ue s ove r a l i f e t i m e T he r ol e of e xpe r i e nc e c a n be pr obe d i n t hi s c a s e by m e a s ur i ng t he vul ne r a bi l i t y of young a nd o l d t o i l l us i ons a nd c ons t a nc i e s R e s e a r c he r s w ho s e e k f i ne r c ont r ol ove r t he l e a r ni ng e nvi r onm e nt c a n e m p l oy a ny of a num be r of o t he r a ppr oa c he s E nr i c hm e nt t e c hni que s e xpos e s ubj e c t s t o t he t o be di s c r i m i na t e d s t i m ul i dur i ng a f a m i l i a r i z a t i on pe r i o d. I t i s e s s e nt i a l w i t hi n t hi s a ppr oa c h t ha t s ubj e c t s be e qua l l y r e i nf o r c e d f or a l l s t i m ul us l e ve l s C l a s s i c a l l e a r ni ng s t udi e s i n P L ha ve pa i r e d a s t i m ul us a nd a r e s pons e ( us ua l l y a na m i ng or m ot or r e s pons e ) B y pa i r i ng a pa r t i c ul a r r e s pons e w i t h a n a ve r s i ve s t i m ul us ( e g s hoc k) r e s e a r c he r s c a n i nve s t i ga t e t he r ol e of m ot i va t i on i n pe r c e pt i on O f pa r t i c ul a r i nt e r e s t i n t he pr e s e nt c ont e xt i s t he f i na l va r i e t y of c ont r ol l e d e xpe r i e nc e e xpe r i m e nt t he s t a nda r d pr a c t i c e a ppr o a c h. W i t hi n t hi s pa r a di gm a s ubj e c t i s i ns t r uc t e d t o m a ke a s e ns or y di s c r i m i na t i on, us ua l l y s i m pl e ove r a s e r i e s of m a ny t r i a l s S ubj e c t s a r e pr ovi de d w i t h s om e f o r m o f f e e dba c k r e ga r di ng t he i r pe r f o r m a nc e w hi l e s t i l l e nga ge d i n t he t a s k. T he l e ve l of t he s t i m ul us s i gn a l w i l l t ypi c a l l y r e m a i n c ons t a nt ove r t e s t t r i a l s s o t ha t i m pr ove m e nt s o r de c r e m e nt s i n p e r f or m a nc e c a n be p r ope r l y m e a s ur e d. S i nc e l e a r ni ng i s i ns t a nt i a t e d t h r oughout t he br a i n a nd ha s a r ol e i n a l m os t a l l be ha vi or s m a ny r e s e a r c he r s ha ve s ugge s t e d t ha t P L c a nnot r i ght l y be c a l l e d pe r c e pt ua l a t a l l ( P yl ys hyn, 1999) T he or i s t s w ho t a ke a n e xpa n s i ve vi e w of t he r ol e o f a t t e nt i on i n vi s ua l pr oc e s s i ng, m i ght i nt e r pr e t a l m os t a l l P L a s a t s om e l e ve l a s hi f t i n a t t e nt i on\n3 E ps t e i n a r gue s t ha t m os t d i s put e s a bout w he t he r i m pr ove m e nt s i n di s c r i m i na t i on pe r f or m a nc e c ons t i t ut e P L or s om e ot he r m or e c ogni t i ve l e a r ni ng boi l dow n t o di s put e s r e ga r di ng t he de f i ni t i on o f pe r c e pt i on T w o c om m on c r i t e r i a f or de f i ni ng a pr oc e s s a s pe r c e pt ua l a r e i m m e di a c y a nd s t i m ul us de pe nde nc e T he f i r s t c r i t e r i on i m m e di a c y, c a n be s a t i s f i e d by i m pl e m e nt i ng c ont r ol s t ha t m i ni m i z e t he i nf l ue nc e o f hi ghe r or de r j udgm e nt s D i s c r i m i na t i on t a s ks t ha t i nvol ve d i c hot om ous de c i s i ons r e ga r di ng e qui pr oba bl e s t i m ul us c l a s s e s c a n m i ni m i z e t he r ol e of s t r a t e gy. T he s e c ond c r i t e r i on, s t i m ul us de pe nde nc e i ndi c a t e s t ha t va r i a t i on i n t he be ha vi or of t he s ubj e c t m us t be e xpl a i na bl e i n t e r m s of s t i m ul us pr ope r t i e s T he T he m a t i c A ppe r c e pt i on T e s t f or e xa m pl e w oul d not be c ons i de r e d pe r c e pt ua l be c a us e t oo l i t t l e o f t he s ubj e c t s ve r ba l be ha vi or i s e xpl a i ne d by t he i l l us t r a t i ons P L t a s ks t ha t i nvol ve ps yc hophys i c a l j udgm e nt s r e ga r dl e s s of m oda l i t y, c a n be c ont r ol l e d s o a s t o i nc r e a s e t he l i ke l i hood t ha t l e a r ni ng i s i n f a c t pe r c e pt ua l P L i s e vi de nt i n a num be r of vi s ua l pe r c e pt i on t a s ks i nc l udi ng m ot i on d i s c r i m i na t i on ( M a t t he w s & W e l c h, 1997) s pa t i a l f r e que nc y di s c r i m i na t i on ( F i ne & J a c obs 2000) a nd hype r a c ui t y t a s ks ( F a hl e 1991 ) D e s pi t e m uc h p r o gr e s s t ow a r ds unde r s t a ndi ng t he pe r c e pt ua l a nd ne ur a l m e c ha ni s m s unde r l yi ng t he s e i m pr ove m e nt s i n pe r f or m a nc e m a ny que s t i ons r e ga r di ng P L r e m a i n una ns w e r e d. T he r ol e of a t t e nt i on i n P L t a s ks r e m a i ns a n a r e a of a c t i ve i nqu i r y. S e e m i ngl y c onf l i c t i ng r e s ul t s i ndi c a t e t he c e nt r a l i t y o f a t t e nt i on i n c e r t a i n pe r c e pt ua l t a s ks ( F a hl e 2004) a nd i t s i r r e l e va nc e i n ot he r s ( W a t a na be e t a l 2002) Q ue s t i ons r e m a i n r e ga r d i ng t he l oc us of t h e c ha nge s t ha t c ha r a c t e r i z e P L ( G i l be r t e t a l 2001) I m p r ove m e nt s i n c e r t a i n t a s ks de m ons t r a t e or i e nt a t i on s pe c i f i c i t y ( P oggi o e t a l 1992) w hi l e i m pr ove m e nt s i n ot he r t a s ks r e t a i n e ye a nd l oc a t i on s pe c i f i c i t y ( F a hl e\n4 E de l m a n, P oggi o, 1995; K a r ni & S a gi 199 1; A hi s s a r & H oc hs t e i n, 1997) T h i s poor o r a bs e nt t r a ns f e r of l e a r ni ng w oul d s e e m t o i ndi c a t e t ha t l e a r ni ng oc c ur s e a r l y i n v i s ua l s i gna l pr oc e s s i ng. H ow e ve r de s pi t e t he l i m i t e d ge ne r a l i z a t i on of l e a r n i ng i n one por t i on of t he vi s ua l f i e l d t o a not he r t he r e i s e vi de nc e t ha t c ont e xt s hi f t s i n t he f or m of c onf i gur a t i ona l c ha nge s i n pa t t e r ns f a l l i ng on ot he r por t i ons of t he v i s ua l f i e l d, c a n a t t e nua t e P L i n t he t r a i ne d r e gi on S om e ha ve hyp ot he s i z e d t ha t hor i z ont a l c onne c t i ons f r om t he por t i ons o f t he vi s ua l c or t e x t ha t r e pr e s e n t ot he r a r e a s of t he v i s ua l f i e l d p l a y a m odul a t or y r ol e i n P L ( C r i s t e t a l 1997) P e r c e pt ual L e ar ni ng M e c hani s m s A ny of a num be r o f ne ur a l m e c ha ni s m s m a y unde r l i e pe r c e pt ua l l e a r ni ng ( G i l be r t e t a l 2001) T he f i r s t pos s i bi l i t y i nvol ve s a n i nc r e a s e i n t he a r e a of c or t e x us e d t o r e pr e s e nt a s pe c i f i c s t i m ul us di m e ns i on or por t i on of t he vi s ua l f i e l d. I n s om e c i r c um s t a nc e s r e c r ui t m e nt of a ddi t i ona l ne u r ona l popul a t i ons m a y pe r m i t e nha nc e d pr oc e s s i ng by i nc r e a s i ng t he s i gna l t o n oi s e r a t i o ( H os hi no, 2004) W i t h i n t hi s e s s e nt i a l l y c or r e l a t i ve he bbi a n m ode l P L r e s ul t s f r om e i t he r pot e nt i a t i on or de pr e s s i on of c e l l a s s e m bl i e s i n r e s pons e t o t he t e m por a l r e l a t i on s hi p be t w e e n t he c l i c k t r a i ns f or e a c h a s s e m bl y. T hi s i nt e gr a t i on of l a r ge r popul a t i ons o f ne ur ons pe r m i t s gr e a t e r r e pr e s e nt a t i ona l f i de l i t y a l ong t he r e l e va nt s t i m ul u s di m e ns i on. A n a l t e r na t i ve a c c ount i nvol ve s s ha r pe ne d t uni ng c ur ve s ( S he i nbe r g & L ogot he t i s 2002 ) T he r a t e of a f i r i ng ne u r on c ha n ge s i n r e s pons e t o c e r t a i n s t i m ul us pr ope r t i e s ( e g l i ne a r i t y, or i e nt a t i on) T he pe a k of t he s pi ke f r e que nc y di s t r i but i on r e pr e s e nt s t he opt i m a l l e ve l o f s om e s t i m ul us di m e ns i on r e l e va nt t o t he s ys t e m i n w hi c h t he ne ur on i s f unc t i oni ng. P e r c e pt ua l l e a r ni ng m a y i nvol ve a s ha r p e ni ng of t ha t c ur ve s o\n5 t ha t t he ne ur on r e s ponds t o a n e ve r na r r ow e r ba nd of t he r e l e va nt di m e ns i on. F o r e xa m pl e r e s e a r c he r s ha ve f ound t ha t i ndi vi dua l c e l l s i n t he i n f e r i or t e m por a l c or t e x a r e di f f e r e nt i a l l y r e s pons i ve t o a l e a r ne d s i ngl e vi e w o f a n a r t i f i c i a l obj e c t ( L ogo t he t i s e t a l 1995) T hi s t ype of l e a r ni ng a l m os t r e pr e s e nt s a n a nt i H e bbi a n vi e w i n w hi c h e a c h c e l l a t t e m pt s t o or t hogona l i z e i t s r e pr e s e nt a t i on r e l a t i v e t o a l l o t he r c e l l s ( G i l be r t e t a l 2001 ) I n t hi s w a y, t he c e l l s s pr e a d t o r e pr e s e nt a l a r ge por t i on of t he s t i m ul us d i m e ns i on w i t h e a c h c e l l s pe c i a l i z e d t o r e s pond t o a n e ve r na r r ow e r ba nd o f s t i m ul a t i on A t hi r d pos s i bl e m e c ha ni s m i nvol ve s i nc r e a s e s i n ne ur a l s ync hr ony ( T hor pe 2004) R a t he r t ha n us i ng a ddi t i ona l l oc a l ne ur on s t o e nc ode a nd pr oc e s s t he s t i m ul us di s t a nt ne ur ons m a y s uppor t p r oc e s s i ng by f i r i ng i n s om e t e m por a l r e l a t i on t o t he r e l e va nt di m e ns i on. I n m a ny t he o r i s t s c onc e pt ua l i z a t i ons of P L a t t e nt i on i s gi ve n a c e nt r a l r ol e i n l e a r ni ng. I n s om e m ode l s a t t e n t i on i s r e qui r e d t o i de nt i f y t he s t i m ul us di m e ns i on r e l e va nt t o r e qui r e d di s c r i m i na t i on I n ot he r s a t t e nt i on s e r ve s a s a t i m e m a r ki ng m e c ha ni s m t ha t l a be l s t he m om e nt a t w hi c h t he di s c r i m i na t i on w a s m a de s o t ha t l e a r ni ng c a n oc c ur i n r e l a t i on t o t ha t s p e c i f i c ope r a t i on R e ga r dl e s s of t he s pe c i f i c f unc t i on a t t r i but e d t o a t t e nt i on i n t he s e m ode l s a l m os t a l l a c c ount s of pe r c e pt ua l l e a r ni ng l e a ve a r ol e f or a t t e nt i on P e r ha ps t he e f f e c t s of a t t e nt i on i n pe r c e pt ua l l e a r ni ng c a n be c l a r i f i e d us i ng a f f e c t i ve m a ni pul a t i ons T hi s s t udy w i l l pr e s e nt pa r t i c i pa nt s w i t h va l e nc e d pi c t ur e s t i m ul i i n a n a t t e m pt t o m a ni pul a t e a t t e nt i on a nd d e t e r m i ne t he i nf l ue nc e of e m ot i ona l l y dr i ve n a t t e nt i on t o t he P L t a s k.\n6 E m ot i on and A t t e nt i on M ode l s of e m ot i on ha ve i nt e g r a t e d e vol ut i ona r y t h e or y t o g r e a t e xpl a na t or y e f f e c t T he or i s t s ha ve i de nt i f i e d a num be r of dom a i ns i n w hi c h e m ot i on m a y ha ve i nf l ue nc e d f i t ne s s but of pa r t i c ul a r i nt e r e s t a r e t he a r e a s of a t t e nt i on, pe r c e pt i on, a nd l e a r ni ng. R e s e a r c h i nt o e vol ut i on ps yc hol o gy w a s i ni t i a l l y e xpa ns i ve a nd f e c kl e s s w i t h a w i de va r i e t y of unt e s t a bl e t he or i e s pr e s e nt e d f o r va r i e d be ha vi or s H ow e ve r e xpl i c i t c r i t e r i a ha ve be e n f or m ul a t e d t o de f i ne t he bounda r i e s w i t hi n w hi c h a n e m ot i on c a n be a c c ur a t e l y l a be l e d a s a n a da pt a t i on ( T ooby & C os m i de s 1990) F or a n e m ot i on t o be c ons i de r e d a n a da pt a t i on, a nc e s t r a l popul a t i ons f o und t he m s e l ve s pr e s e nt e d w i t h a s i t ua t i on w i t h gr e a t e nough f r e que nc y a s t o c ons t i t ut e a n a da pt i ve pr obl e m T hi s s i t ua t i on m us t be i de nt i f i a bl e by s i t ua t i o n s pe c i f i c c ue s A ddi t i ona l l y, t he s e c ue s m us t be m oni t or e d by a l gor i t hm s t ha t de t e c t s i t ua t i ons a nd t he n r e a c t i n a m a nne r t ha t i nc r e a s e s f i t ne s s C l e a r l y a n a c c ount l i ke t hi s e nc ount e r s di f f i c ul t y w he n e xpl a i ni ng e m ot i ons s uc h a s s e nt i m e nt a l i t y or t he d i s t i nc t i on be t w e e n e nvy a nd j e a l ous y ( A ve r i l l 1997 ) H ow e ve r s om e e m ot i ons l e nd t he m s e l ve s t o t hi s t ype o f a na l ys i s qui t e w e l l F e a r i t w oul d s e e m f ul f i l l s a c l e a r a da pt i ve f unc t i on T h r e a t s i n t he e nvi r onm e nt w e r e p r e s e nt i n a bunda nc e a nd c ons t i t u t e d a n a da pt i ve pr obl e m M or e ove r t h e s e s i t ua t i ons c a n be qui c kl y de t e c t e d ut i l i z i ng vi s ua l c ue s E m ot i ons ha ve a n unde r l yi ng phys i ol ogi c a l r e a l i t y t ha t ha s i m pl i c a t i ons f or t he w a y t he br a i n p r oc e s s e s vi s ua l s t i m ul i ( K a nde l e t a l 2000) E vol ut i on ha s e qui ppe d hum a ns w i t h t he a bi l i t y t o r a pi dl y c a t e gor i z e v i s ua l s t i m ul i i nt o a ppe t i t i ve o r a ve r s i ve c a t e gor i e s ( B a r & N e t a 2006) T hi s c a t e gor i z a t i o n i s i nc r e di bl y f a s t a nd r obus t c a pa bl e of di s c r i m i na t i ng t he e m ot i ona l va l e nc e of i m a ge s i n t he s pa n of a s i ngl e f r a m e of vi de o\n7 ( M a l j kovi c M a r t i ni & F a r i d, 2004) P r e s e nt i ng s ubj e c t s w i t h t hr e a t e ni ng i m a ge s ( e g. a s na r l i ng dog) a c t i va t e s br a i n s ys t e m s a s s oc i a t e d w i t h de f e ns e T he r ol e of t he a m ygda l a i n r e gul a t i ng be ha vi o r a l r e s pons e s t o t he e nvi r on m e nt w hi l e i m pl i c a t e d f o r s om e t i m e ( K l uve r & B uc y, 1937) ha s onl y r e c e nt l y be gun t o be t r ul y unde r s t ood. T he hypot ha l a m us c ont r ol s e xpr e s s i ons of f e a r i n t he p e r i phe r a l ne r vous s ys t e m I n c ont r a s t t he a m ygda l a i s r e s pons i bl e f or c ha nge s i n t he c e nt r a l ne r v ous s ys t e m i n r e s pons e t o t hr e a t e ni ng s t i m ul i T he a m ygda l a m e di a t e s bot h i nbor n a s w e l l a s l e a r ne d e m ot i ona l r e s pons e s i n a l l s e ns or y m oda l i t i e s ( K a nde l e t a l 2000) I n a m o r e c onc r e t e e xa m pl e t he s e que nc e of r e s pons e s i ni t i a t e d by t he br a i n i n r e s p ons e t o a t hr e a t e ni ng f a c e i s be c om i ng be t t e r u nde r s t ood. I n one a c c ount t he f a c e i s f i r s t e nc ode d i n t he i nf e r i or t e m por a l c o r t e x, w hi c h pr oc e s s e s f a c i a l e xpr e s s i on a nd ga z e di r e c t i on i n a pr e a t t e nt i ve m a nne r ( S oa r e s & O hm a n, 1993) T ypi c a l l y t he i nf e r i o r t e m por a l c or t e x ne xt s i gna l s t he a m ygda l a w i t h t he e m ot i ona l c ont e nt o f t he f a c e s T he a m ygda l a t he n a c t i va t e s a ppr opr i a t e be ha vi or a l a u t onom i c a nd e ndoc r i na l r e s pons e s A ddi t i ona l l y, t he r e a r e a l s o phyl oge ne t i c a l l y ol de r c onne c t i ons f r om t he t ha l a m us t o t he a m ygda l a T he s e c onne c t i ons m a y pr ovi de a r a pi d t r a c k f or pr oc e s s i ng t hr e a t s w i t hout t he e l a bor a t i on t ha t us ua l l y oc c ur s i n t he t e m por a l l obe T he s e s ubc or t i c a l c onne c t i ons s e e m t o pr ovi de c oa r s e but us e f ul i n f or m a t i on r e ga r di ng obj e c t s i n t he vi s ua l f i e l d. ( F e ndr i c k e t a l 2001 ) B e ha vi or a l r e s pons e s m a y i nc l ude or i e nt i ng be ha vi or f l i nc hi ng, or t he t e ns i ng o f m us c l e s i n pr e pa r a t i on f o r a b l ow A ut onom i c r e s pons e s i nc l ude t he a c t i va t i on of t he s ym pa t he t i c ne r vous s ys t e m A c t i va t i on o f t he s ym pa t he t i c ne r vous s ys t e m r e s ul t s i n i nc r e a s e d he a r t r a t e de c r e a s e d s a l i va t i on, de c r e a s e d di ge s t i on, a nd a hos t of ot he r e f f e c t s\n8 on bi ol ogi c a l s ys t e m s E ndoc r i na l r e s pons e s i nc l ude s t i m ul a t i on of t he H P A or H ypot ha l a m i c P i t ui t a r y A d r e na l a xi s T he H P A a xi s f l oods t he bl ood s uppl y w i t h hor m one s t ha t pr e pa r e t he body f or de a l i ng w i t h a t hr e a t C or t i s ol a dr e na l i ne a nd ot he r hor m one s a r e i nvol ve d i n t hi s t h r e a t s i gna l i ng, pr e pa r a t i on, a nd r e c ove r y ( K a nde l e t a l 2000) I n a s t udy us i ng a nt e r ogr a d e t r a c e r s i n t he a m ygda l oi d c om pl e x of M ac ac a f as c i c ul ar i s r e s e a r c he r s di s c ove r e d pr oj e c t i ons f r om t he a m ygda l a ba c k t o a r e a s r e s pons i bl e f or e a r l y vi s ua l pr oc e s s i ng, na m e l y, T E a nd V 1 ( F r e s e & A m a r a l 2005, A m a r a l e t a l 2003 ) R e s e a r c he r s hypot he s i z e t ha t t he s e c onne c t i ons m a y m odul a t e vi s ua l pr oc e s s i ng i n r e s pons e t o t hr e a t r e l a t e d s t i m ul i T he s e f e e dba c k l i ke p r oj e c t i ons c oul d s uppor t a pe r c e pt ua l s ys t e m de s i gne d t o s e l e c t i ve l y a m pl i f y r e pr e s e nt a t i ons t ha t pr ovi de vi t a l i nf or m a t i on a bout t he e nvi r on m e nt a nd, a s a r e s ul t m a y gui de be ha vi or i n t hr e a t e ni ng s i t ua t i ons T he s e c onne c t i ons how e ve r a r e onl y p r e s um a bl y e xc i t a t or y. T he s pe c i f i c f unc t i on of t he s e r e c i pr oc a l c onne c t i ons i s ye t t o be e l a bor a t e d. R e c e nt e vi de nc e s ugge s t s t ha t t he br a i n i s bi ol ogi c a l l y pr e pa r e d t o a ddr e s s c e r t a i n t hr e a t s c om m on t o ou r e nvi r onm e nt of a da pt a t i on, s uc h a s s na ke s s pi de r s a nd ot he r t hr e a t e ni ng c r e a t ur e s ( S oa r e s & O hm a n, 1993) I n a c ondi t i oni ng e xpe r i m e nt r e s e a r c he r s pr e s e nt e d pa r t i c i pa nt s w i t h e i t he r ne ut r a l o r a ve r s i ve pi c t ur e s t i m ul i a nd de m ons t r a t e d di f f e r e nc e s i n c ondi t i oni ng e f f e c t s t ha t c oul d onl y be e xpl a i ne d vi a i nna t e di f f e r e nc e s i n pr oc e s s i ng s pe e d. A ddi t i ona l l y, pa r t i c i pa nt s pr e s e nt e d w i t h m a s ke d t hr e a t e ni ng s t i m ul i de m ons t r a t e d a c ha r a c t e r i s t i c e l e c t r ophys i ol ogi c a l r e a c t i on gr e a t e r t ha n w ha t w a s obs e r ve d w i t h m a s ke d ne ut r a l s t i m ul i de s pi t e t he f a c t t ha t bot h p r e s e nt a t i ons w e r e s ubt hr e s hol d ( C a r r e t i e e t a l 2004)\n9 W hi l e s om e ha ve r e f e r r e d t o t he pr oc e s s e s us e d t o i de nt i f y a nd p r e pa r e f o r t hr e a t e ni n g s t i m ul i a s a ut om a t i c ( e g C a r r a t i e e t a l 2004) ot he r s a r gua bl y c or r e c t l y r e f e r t o t he s e pr oc e s s e s a s pr e a t t e nt i ve ( e g. S oa r e s & O hm a n, 1993; C om pt on, 2003 ) P r e a t t e nt i ve i s t he p r e f e r r e d t e r m be c a us e a ut om a t i c pr oc e s s e s a r e not gove r ne d by r e s our c e l i m i t a t i ons w hi c h a r e not o r i ous l y ha r d t o ope r a t i ona l i z e P r e a t t e nt i ve pr oc e s s i ng ha s a num be r of c ha r a c t e r i s t i c s t ha t di s t i ngui s h i t f r om a ut om a t i c pr oc e s s i ng ( L oga n, 1992) A s one m i ght a s s um e t hi s pr oc e s s i ng oc c ur s i n t he a bs e nc e of a t t e nt i on. P r e a t t e nt i ve pr oc e s s i ng i s a n obl i ga t or y pr oc e s s i ng of a l l i nf o r m a t i on i n t he s e ns or y f i e l d s i m ul t a ne ous l y. G r oupi ng by s i m i l a r i t y a nd p r oxi m i t y a r e e xa m pl e s of t hi s s or t of pr oc e s s a c c or di ng t o L oga n. M a ny e a r l y c ogni t i ve s c i e nt i s t s di d not m a i nt a i n a di s t i nc t i on be t w e e n pr e a t t e nt i ve a nd a ut om a t i c pr o c e s s i ng, but r e c e nt e vi de nc e s ugge s t s t ha t s uc h a di s t i nc t i on m i ght be us e f ul I f a ut om a t i c pr oc e s s i ng i s s i m pl y de f i ne d a s pr oc e s s i ng i n t he a bs e nc e of a t t e nt i on, t he n, of c ou r s e pr e a t t e nt i ve p r oc e s s i ng i s a ut om a t i c L oga n i de nt i f i e s t w o pr obl e m s w i t h t hi s de f i ni t i on ( w h i c h he r e f e r r e d t o a s t he m oda l vi e w ) F i r s t i t de f i ne s a ut om a t i c i t y n e ga t i ve l y, w i t hout i de nt i f yi ng t he m e c ha ni s m s a nd pr oc e s s e s r e s pons i bl e f or a ut om a t i c pr oc e s s i ng. A ddi t i ona l l y w i t h r e s pe c t t o l e a r ne d a ut om a t i c i t y i t doe s not e xpl a i n how a t t e nt i on c a n be w i t hdr a w n f r om c ogni t i ve a c t s t ha t a r e r e pe a t e d of t e n e nough t o di m i ni s h t he i r c a pa c i t y de m a nds F o r t he s e r e a s ons a nd s e ve r a l ot he r s gr ounde d i n t he t r a di t i ona l e a r l y vs l a t e s e l e c t i on l i t e r a t ur e i t i s be s t t o c ons i de r t he pr oc e s s e s r e s po ns i bl e f or a t t e nt i on t o va l e nc e d s t i m ul i a s pr e a t t e nt i ve r a t he r t ha n a ut om a t i c R e c e nt c ogni t i ve a nd i nf or m a t i on pr oc e s s i ng a ppr oa c he s t o hum a n ps yc hol ogy ha ve hi ghl i ght e d t he i n f or m a t i ve a s pe c t of a f f e c t i v e i nf or m a t i on ( C om pt on 2003)\n10 R e s e a r c he r s a r gue t ha t s i nc e s e l e c t i ve a t t e nt i on i s us e d t o pa r e dow n t he w a s h of da t a a c r os s t he s e ns e s a nd e m ot i ona l s i gni f i c a nc e of t e n m a r ks bi ol ogi c a l l y i m po r t a nt da t a i t i s l i ke l y t he m i nd us e s e m ot i on a l s i gni f i c a nc e t o i de n t i f y obj e c t s t ha t ough t t o be a t t e nde d ( a l m os t a l w a ys a t t he e xpe ns e of o t he r s ) E m ot i on a l r e a c t i ons t o s t i m ul i a l m os t a l w a ys i nvol ve t he f u r t he r i ng or i m pe di ng of s om e bi ol ogi c a l goa l ( A r nol d 1960 ) I n or de r f o r e m ot i ona l t a ggi ng o f s t i m ul i t o ha ve a ny ut i l i t y i n r a pi d de pl oym e nt of s e l e c t i ve a t t e nt i on, e m ot i ona l pr oc e s s i ng of a f f e c t i ve s t i m ul i w oul d ne e d t o oc c ur qui t e qui c kl y ( C om pt on, 2003) E vi de nc e f r om e l e c t r op hys i ol ogi c a l s t udi e s i ndi c a t e d br a i n a c t i vi t y i n t he ve nt r om e di a l p r e f r ont a l c or t e x 150 m s a f t e r s t i m ul us ( s pi de r i m a ge ) ons e t ( C a r r i e t e e t a l 2004) T he ve nt r om e di a l pr e f r ont a l c or t e x i s be l i e ve d t o be i nvol ve d i n t hr e a t pr oc e s s i ng. I n t hi s s t udy t he t h r e a t e ni ng s t i m ul i w e r e m a s ke d a nd t he pa r t i c i pa nt s ha d no a w a r e ne s s of t he t h r e a t e ni ng s t i m ul i T hi s w oul d s e e m t o pr ovi de a ddi t i ona l e vi de nc e t ha t t hr e a t s a r e pr oc e s s e d pr e a t t e nt i ve l y. P s yc hophys i ol ogi c a l s t udi e s w hi c h m oni t or e d bi ol ogi c a l i ndi c a t or s of t hr e a t de t e c t i on ( e g. bl ood p r e s s ur e s ki n c onduc t a nc e he a r t r a t e c or r uga t or a c t i vi t y) f ound a s i m i l a r r a pi d r e s pons e w i t h r e l i a bl e c ha nge s w i t hi n 500 m s o f s t i m ul us ons e t ( C odi s pot i e t a l 2 001) C odi s pot i a nd c ol l e a gue s pr e s e nt e d s t i m ul i t o pa r t i c i pa nt s f or 500 m s a nd f o und s i m i l a r pa t t e r ns o f e m ot i ona l l y l i n ke d phys i ol ogi c a l r e s pons e a s pr e vi ous s t udi e s i n w hi c h s t i m ul i w e r e pr e s e nt e d f or 6 s I t w oul d s e e m a s t hough bi ol ogi c a l p r e pa r e dne s s f or t hr e a t s r e a c he s a s ym pt ot e qui c kl y, r e m a i ni ng s t a bl e a f t e r t he f i r s t 500 m s R e s e a r c he r s a r gue t ha t t hi s i nd i c a t e s t ha t s t i m ul i c ont i nue t o be p r oc e s s e d e ve n a f t e r pr e s e nt a t i on. I t s e e m s t ha t not onl y t he c e nt r a l ne r vous s ys t e m but t he pe r i phe r a l ne r vous s ys t e m a s w e l l c a n r e s pond t o e m ot i ona l s t i m ul i i n w e l l unde r one s e c ond. T hi s w i ndow o f t i m e t ha t w oul d pe r m i t s e l e c t i ve\n11 a t t e nt i on t o ut i l i z e e m ot i ona l s i gni f i c a nc e a s a s our c e of i nf o r m a t i on i n s i t ua t i ons t ha t w oul d r e qui r e r a pi d r e s pons e s L e s i on s t udi e s i nvol vi ng bi l a t e r a l s i m ul t a ne ous s t i m ul a t i on pr ovi de c onve r gi ng e vi de nc e t ha t t hr e a t r e l a t e d s t i m ul i a r e pr e f e r e nt i a l l y pr oc e s s e d ( V ui l l e um i e r & S c hw a r t z 2001) T w o s ubj e c t s w i t h r i ght pa r i e t a l f oc a l l e s i o ns de m ons t r a t e d e xt i nc t i on of br i e f l y pr e s e nt e d s t i m ul i i n t he i r l e f t vi s ua l f i e l d H ow e ve r w he n i m a ge s of s pi de r s w e r e pr e s e nt e d i n t he l e f t vi s ua l f i e l d s ubj e c t s w e r e a bl e t o c or r e c t l y i de nt i f y i m a ge s a s a c c ur a t e l y a s c ont r ol s I t s houl d be not e d t ha t t he s pi de r s w e r e m a t c he d w i t h f l ow e r s i n t e r m s of l ow l e ve l vi s ua l pr ope r t i e s by r e a r r a ngi ng t he l i ne s i n t he i l l us t r a t i on E m ot i ona l s a l i e nc e e nga ge s a t t e nt i on. C odi s pot i e t a l ( 2001) pr e s e nt e d pa r t i c i pa nt s w i t h a n a br up t a udi t or y pr obe w hi l e t h e y w e r e pr e s e nt e d w i t h a f f e c t i ve s t i m ul i T he t ypi c a l r e s pons e t o a 50 m s pr e s e nt a t i on of a 103 dB t one i s a s t a r t l e r e s pons e w hi c h a l m os t a l w a ys e nt a i l s a bl i n k. B y m e a s ur i ng bl i nk s uppr e s s i on, r e s e a r c he r s hope d t o e va l ua t e a t t e nt i ona l i nvol ve m e nt w i t h t he a f f e c t i ve s t i m ul i B l i nks w e r e i nhi bi t e d l onge r f o r e m ot i ona l l y va l e nc e d, e i t he r pl e a s a nt or unpl e a s a nt s t i m ul i H ow e ve r w he n s ubj e c t di d b l i nk, t he m a gn i t ude o f t he s t a r t l e r e f l e x w a s gr e a t e r w he n pa r t i c i pa nt s w e r e pr e s e nt e d w i t h ne ga t i ve a s oppo s e d t o pos i t i ve or ne ut r a l s t i m ul i S i m i l a r r e s ul t s obt a i ne d i n a s t udy by C ut hbe r t e t a l ( 1998 ) R e s e a r c he r s c onc l ude d t ha t a f f e c t i ve i nf or m a t i on i s us e d t o m odul a t e t he s t a r t l e r e f l e x, l e a di ng t o he i ght e ne d s t a r t l e r e a c t i ons i n t he pr e s e nc e of ne ga t i ve o r t h r e a t e ni ng, s t i m ul i O t he r e vi de nc e f o r a s t r ong r e l a t i ons hi p be t w e e n e m ot i on a nd a t t e nt i on c a n be f ound i n a s t udy by A nde r s on & P he l ps ( 2001) U s i ng a r a pi d s e r i a l vi s ua l pr e s e nt a t i on pa r a di gm r e s e a r c he r s de t e r m i ne d t ha t t he a t t e nt i ona l b l i nk i s a t t e nua t e d w he n t he s e c ond t a r ge t i s e m ot i ona l l y s a l i e nt\n12 F ut he r m or e t hi s a t t e nua t i on w a s not e vi de nt i n a p a r t i c i pa nt w i t h da m a ge t o t he a m ygda l a A r e c e nt s t udy by P he l ps e t a l ( 2006 ) m a y f ur t he r i l l um i na t e t hi s r e l a t i ons hi p be t w e e n a t t e nt i on a nd e m ot i on I n a n i nve s t i ga t i on of t r a ns i e nt c ove r t a t t e nt i on, r e s e a r c he r s pr e s e nt e d pa r t i c i pa nt s w i t h a n or i e nt a t i on di s c r i m i na t i on t a s k us i ng ga bo r pa t c he s o f va r yi ng c ont r a s t T he pa t c he s c oul d be pr i m e d by a f e a r f ul or a ne ut r a l f a c e i n t he c e nt e r of t he s c r e e n. P a r t i c i pa nt s ha d l ow e r c o nt r a s t t hr e s hol ds w he n pr e s e nt e d w i t h t he f r i ght e ne d, a s oppos e d t o t he ne ut r a l f a c e I n a s e c ond e xpe r i m e nt pa r t i c i pa nt s w e r e pr e s e nt e d w i t h a ne ut r a l or f e a r f ul f a c e c ue i n e i t he r a pe r i phe r a l l oc a t i on or di s t r i but e d a bout t he s c r e e n. T he l oc a t i on of t he pe r i phe r a l c u e c ha nge d a c r os s t r i a l s P a r t i c i pa nt s ha d l ow e r c ont r a s t t h r e s hol ds w i t h t he f r i ght e ne d f a c e s i n bot h t h e pe r i phe r a l a nd di s t r i but e d c ondi t i ons I nt e r e s t i ngl y, t he s e r e s ul t s s how i nde pe nde nt c ont r i but i ons of e m ot i on a nd s pa t i a l a t t e nt i on s uc h t ha t t he pe r i phe r a l c ue i n t he qua d r a nt of t he s c r e e n w he r e t he t a r ge t w a s t o a ppe a r r e s ul t e d i n t he l ow e r c ont r a s t t hr e s hol d t ha n t he di s t r i but e d c ue l i ke l y be c a us e t he di s t r i but e d c ue s pr e a d a t t e nt i on e ve nl y a bout t he s c r e e n. H ow e ve r t he di s t r i but e d f e a r f ul c ue s t i l l r e s ul t e d i n l ow e r t h r e s hol ds w he n c om pa r e d t o t he d i s t r i but e d ne ut r a l c ue R e s e a r c he r s c onc l ude t ha t r e c i pr oc a l p r oj e c t i ons f r om t he a m ygda l a w hi c h pr oc e s s e s t hr e a t s pr e a t t e nt i ve l y, l oop ba c k t o t he e a r l y vi s ua l a r e a s of t he e xt r a s t r i a t e c or t e x, i nc r e a s i ng t he s pe e d a nd a c c ur a c y of vi s ua l pr oc e s s i ng. A ddi t i ona l l y, w hi l e t he e f f e c t s of e m ot i on on p e r c e pt i on m a y c om e a bout i n t hi s e xpe r i m e nt vi a t he m ode r a t i ng i n f l ue nc e of t r a ns i e nt c ove r t a t t e nt i on, t he r e i s e vi de nc e t ha t e m ot i on m a y ha ve a pot e nt i a t i ng e f f e c t on vi s ua l pr oc e s s i ng e ve n i n t he a bs e nc e of a t t e nt i on. W he n t he c ue w a s di s t r i but e d e ve nl y a c r os s t he s c r e e n, s o t he r e w a s no c ue f or\n13 c ove r t a t t e nt i on t o us e t o l oc a l i z e t he t a r ge t t he r e s t i l l w e r e l ow e r c ont r a s t t h r e s hol ds T hi s s t udy ut i l i z e d f e a r f ul f a c e s be c a us e f e a r f ul f a c e s pr ovi de a m bi guous i nf o r m a t i on a bout t he e nvi r onm e nt T he i nf o r m a t i on a bout t he e nvi r onm e nt i s a m bi guous i n s o f a r a s i t s i gna l s a t hr e a t but doe s not i de nt i f y i t Z e e l e nbe r g e t a l ( 2006 ) r e c e nt l y f ound t ha t e m ot i o na l l y s i gni f i c a nt w or ds a r e r e c ogni z e d m or e a c c ur a t e l y t ha n ne ut r a l w o r ds i n a t w o a l t e r na t i ve f or c e d c hoi c e e xpe r i m e nt I n t hi s c a s e r e s e a r c he r s w i s he d t o di s e nt a ngl e t he r e l a t i ve c ont r i but i ons of s e ns i t i vi t y a nd bi a s i n pe r c e pt ua l i de nt i f i c a t i on t a s ks i nvol vi ng e m ot i ona l s t i m ul i T he y c onc l ude t ha t bi a s i s l i ke l y no t a f a c t or i n pr e f e r e nt i a l pr oc e s s i ng of e m ot i ona l l y c ha nge d s t i m ul i A s ur pr i s i ng r ol e f or hum a n s c e nt s a s s oc i a t e d w i t h f e a r w a s unc ove r e d i n a r e c e nt s t udy by C he n ( 2006) R e s e a r c he r s e xpos e d f e m a l e s ubj e c t s i n t hi s m e m or y e xpe r i m e nt w i t h hum a n s c e nt s a m pl e s T he s a m pl e s w e r e c ol l e c t e d i n t he unde r a r m s of vol unt e e r s w ho vi e w e d e i t he r ho r r or m ovi e s or doc um e nt a r i e s S ubj e c t s w e r e pr e s e nt e d w i t h one of t he t w o s a m pl e t ype s w hi l e t he y c om pl e t e d a n a s s oc i a t i ve de c i s i on t a s k. T he de c i s i on i nvol ve d i ndi c a t i ng w he t he r t he w or ds i n 320 w o r d pa i r s w e r e a s s oc i a t i ve l y r e l a t e d. W he n t he w or ds a bout w hi c h t he de c i s i on w a s m a de w e r e a s s oc i a t i ve r e l a t e d, s ubj e c t s e xpos e d t o t he s a m pl e c ol l e c t e d f r o m s ubj e c t s w ho vi e w e d t he hor r or m ovi e pe r f or m e d m or e a c c ur a t e l y t ha n t hos e e xpos e d t o t he ot he r s a m pl e T he r e w a s a n i nt e r a c t i on be t w e e n w or d pa i r c ondi t i on a nd s w e a t e xpos ur e c ondi t i on s uc h t ha t s ubj e c t s e xpos e d t o t he t hr e a t s w e a t w e r e s l ow e r t o r e s pond w he n on e of t he w or ds pr e s e nt e d w a s not t hr e a t r e l a t e d.\n14 E ve n s om e t hi ng a s s e e m i ngl y i di os ync r a t i c a s t he pr e f e r e nc e of c om m on obj e c t s s e e m s i nf l ue nc e d by bi ol ogi c a l pr og r a m s t o de t e c t t hr e a t s ( B a r & N e t a 2006 ) R e s e a r c he r s pr e s e nt e d s ubj e c t s w i t h e ve r yda y obj e c t s t ha t c oul d e i t he r be c ha r a c t e r i z e d by l ong, ge nt l e c ur ve s s ha r p di s c ont i nui t i e s o r c o nt r ol obj e c t s w i t h bot h a t t r i but e s O bj e c t s w e r e pa i r e d a c r os s c ondi t i ons s uc h t ha t t o ke ns f or a gi ve n obj e c t ( e g. a w a t c h) w oul d be c ont a i ne d i n bot h t he s ha r p a nd c ur ve d c ondi t i ons A n a ddi t i ona l c ont r ol c ondi t i on s how e d a bs t r a c t m e a ni ngl e s s s ha pe s w i t h e i t he r ge nt l e c ur ve s or s ha r p a ngl e s O f t he r e a l obj e c t s obj e c t s w i t h no s ha r p di s c ont i n ui t i e s w e r e pr e f e r r e d f i r s t f ol l ow e d by obj e c t s w i t h bot h s ha r p a nd c ur ve d s ur f a c e s O bj e c t s w i t h onl y s ha r p f e a t ur e s w e r e pr e f e r r e d l e a s t C ur ve d a bs t r a c t obj e c t s w e r e pr e f e r r e d t o s ha r p obj e c t s i n t he a bs t r a c t c ondi t i on, a s w e l l B a r & N e t a c onc l ude t ha t t hi s bi a s t ow a r ds c ur ve d obj e c t s r e s ul t s f r om t h r e a t e ni ng i m p r e s s i on c a r r i e d by c ont ou r a l o ne W hi l e bot t om up f a c t or s c a n a c c ount f or pa r t o f t h e obs e r ve d i nt e r a c t i ons be t w e e n e m ot i on a nd a t t e nt i on i t i s l i ke l y t ha t t op dow n i nf l ue nc e s a r e a l s o pr e s e nt T he pr e f r ont a l c or t e x pa r t i c ul a r l y i n t he ve nt r om e di a l a nd dor s ol a t e r a l a r e a s ha s s how n r a pi d e l e c t r ophys i ol ogi c a l a nd he m odyna m i c r e s pons e s t o t h r e a t e ni ng s t i m ul i ( C a r r i e t e e t a l 2004) I nt e r e s t i ngl y, t he r e a r e r e c i pr oc a l pr oj e c t i o ns be t w e e n t he ve nt r om e di a l p r e f r ont a l c or t e x a nd t he a m ygda l a s ugge s t i ng t ha t e a c h m a y be c a pa bl e of m odul a t i ng t he e f f e c t s of t he ot he r M uc h e vi de nc e ha s be e n ga t he r e d i n a c l i ni c a l c ont e xt r e ga r di ng t he s e ns i t i vi t y of s ubj e c t s t o va l e nc e d i nf or m a t i on a s a f unc t i on o f c e r t a i n i ndi vi dua l d i f f e r e nc e s va r i a bl e s F ox ( 1993a ) f ound t ha t s ubj e c t s hi gh i n s t a t e a nxi e t y, a s m e a s ur e d S pi e l be r ge r s S T A I a nxi e t y i nde x ( S pi e l be r ge r e t a l 1970) s how e d gr e a t e r l a t e nc i e s i n a n e m ot i ona l S t r oop\n15 t a s k w he n pr e s e nt e d w i t h t hr e a t e ni ng o r ne ut r a l w o r ds H ow e ve r t he s e s a m e hi gh a nxi e t y s ubj e c t s s how e d s i m i l a r de l a ys w he n pr e s e nt e d w i t h ot he r non t h r e a t e ni ng di s t r a c t or c ondi t i ons F ox c onc l ude s t ha t w hi l e t h r e a t e ni ng w or ds do c r e a t e m or e i nt e r f e r e nc e i n a nxi e t y pr one s ubj e c t s t he s e s ubj e c t s m a y s uf f e r f r om a m o r e ge ne r a l s us c e pt i bi l i t y t o di s t r a c t i on or i na bi l i t y t o m a i nt a i n a t t e nt i ona l f oc us I n a s e pa r a t e s t udy, F ox ( 1993b) a l s o de t e r m i ne d t ha t t hos e hi gh i n a nx i e t y a l l oc a t e a t t e nt i on t ow a r ds t hr e a t e ni ng w or ds bu t onl y s oc i a l l y t hr e a t e ni ng w or ds W o r ds a s s oc i a t e d w i t h a phys i c a l t hr e a t di d not c a pt ur e a t t e nt i on i n a nxi ous i ndi vi du a l s R e s e a r c h by C ohe n e t a l ( 1 998) f ound s ubj e c t s hi g h i n s t a t e a nge r a s m e a s ur e d by S pi e l be r ge r s S t a t e T r a i t A nge r E xp r e s s i on I nv e nt or y, w e r e m or e l i ke l y t o e xpe r i e nc e i nt e r f e r e nc e i n a n e m ot i ona l S t r oop t a s k w he n pr e s e nt e d w i t h a nge r r e l a t e d w or ds M a t t he w s e t a l ( 2003) f ound t ha t s ubj e c t s w ho s c or e d hi gh on t he S T A I w e r e m or e l i ke l y t o be e f f e c t i ve l y c ue d t o a t a r ge t l oc a t i on by t he f e a r f ul ga z e of a f a c e t ha n t he ne ut r a l ga z e of t he s a m e f a c e S i m i l a r be ne f i t s of a f e a r f ul ove r a ne ut r a l f a c e di d not obt a i n f or s ubj e c t s w i t h l ow S T A I s c or e s R e c e nt l y, br a i n i m a gi ng s t udi e s ha ve pr ovi de d a dd i t i ona l e vi de nc e t ha t pe r s ona l i t y va r i a bl e s m i ght i n f l ue nc e s e ns i t i vi t y t o t hr e a t e ni ng i n f or m a t i on B i s hop e t a l ( 2004a 2004b ) pr e s e nt e d s ubj e c t s w i t h a pa i r of h ous e s a nd f e a r f ul f a c e s s i m ul t a ne ous l y. S ubj e c t s w e r e c ue d on e a c h t r i a l t o i ndi c a t e w he t h e r e i t he r t he hous e s or f a c e s w e r e t he s a m e or di f f e r e nt W he n t he f a c e s w e r e una t t e nde d by s ubj e c t s w i t h l ow a nxi e t y ( a s m e a s ur e d w / S T A I ) a m ygda l a r e s pons e a s s e s s e d vi a f M R I di m i ni s he d. H ow e ve r w he n t he f a c e s w e r e una t t e nde d by hi gh a nxi e t y s ubj e c t s t he r e w a s no r e duc t i on i n a m ygda l a r e s pons e\n16 N ot a l l r e s e a r c h ha s s uppor t e d t he c ont e nt i on t ha t t hr e a t e ni ng s t i m ul i a r e pr oc e s s e d pr e f e r e nt i a l l y. I n a vi s ua l s e a r c h e xpe r i m e nt by T i ppl e s e t a l ( 2002 ) r e s e a r c he r s f ound no a dva nt a ge f o r t h r e a t e ni ng s t i m ul i R a t he r t he s a m e be ne f i t s t ha t obt a i ne d f or de t e c t i on of t hr e a t e ni ng a ni m a l s a m i d s t pl a nt s w e r e a l s o pr e s e nt f or non t hr e a t e ni ng a ni m a l s a m ong pl a nt s I n f a c t t he s e a r c h s l ope f or t he non t h r e a t e n i ng a ni m a l s w a s l ow e r t ha n t he s e a r c h s l ope f o r t he t hr e a t e ni ng a ni m a l s T he r e s e a r c he r s go on t o s ugge s t t ha t p r e vi ous f i ndi ngs of e nha nc e d pr oc e s s i ng of t hr e a t r e l a t e d s t i m ul i m i ght be due t o i ndi vi dua l di f f e r e nc e s i n s e ns i t i vi t y t o t h r e a t r e l a t e d i n f or m a t i on i n t he e nvi r onm e nt T he r e a r e a num be r of pos s i bl e m e c ha ni s m s by w h i c h e m ot i on c oul d i nf or m a t t e nt i on. L a ng e t a l ( 1998) c onc l ude t ha t pr oj e c t i ons f r om t he a m ygda l a t o t he s e ns or y c or t e x, or vi s ua l pr oc e s s i ng c e nt e r s s pe c i f i c a l l y, m i ght a l l ow e m ot i on t o a s s i gn a t t e nt i ona l pr i or i t i e s A t t e nt i on m i gh t a m pl i f y s i gn a l s l e a di ng t o m or e e l a bor a t e r e pr e s e nt a t i ons i n t he a pp r opr i a t e b r a i n a r e a s ( C o m pt on, 2003 ) A not he r i m por t a nt di s t i nc t i on ha s e m e r ge d w i t h r e s pe c t t o a t t e nt i ona l c a pt ur e a s oppos e d t o s us t a i ne d a t t e nt i on, a nd e m ot i o n. K os t e r e t a l ( 2004 ) w i s he d t o e va l ua t e w he t he r i m m i ne nt t h r e a t c a pt ur e d o r he l d a t t e nt i on A t t e nt i on m i gh t be e nga ge d by t hr e a t s i n t he e nvi r onm e nt but not he l d A l t e r na t i v e l y, a t t e nt i on m i ght not be a t t r a c t e d t o t hr e a t s but w he n i t e nc ount e r s t he m i t m a y be di f f i c ul t f or s ubj e c t s t o m ove a t t e nt i on a w a y. T he r e s e a r c he r s pr e s e nt e d s ubj e c t s w i t h a vi s ua l c ue t ha t s i gna l e d a n a ve r s i ve bur s t of w hi t e noi s e P r e vi ous s t udi e s ha ve s how n e nha nc e d vi s ua l pr oc e s s i ng of s t i m ul i t ha t ha ve a c qui r e d a ve r s i ve a s s oc i a t i ons ( A r m ony & D ol a n, 2002 ) S ubj e c t s w e r e i ns t r uc t e d t o i ndi c a t e i n w hi c h o f t w o pos i t i ons a t a r ge t a ppe a r e d a s qui c kl y a s pos s i bl e\n17 A t t he s a m e t i m e t he l e a r ne d c ue w a s pr e s e nt e d i n one of t w o pos i t i ons E vi de n c e obt a i ne d by m a ni pul a t i ng bot h c ue va l i di t y a nd on s e t de m ons t r a t e d not onl y a t t e nt i ona l c a pt ur e by t he c ue but a l s o s us t a i ne d a t t e nt i on. W hi l e i t w a s f ound t ha t t he c ondi t i one d s t i m ul us bot h a t t r a c t e d a nd he l d a t t e nt i on i n t hi s s t udy, t he d i s t i nc t i on r e m a i ns a n i m por t a nt one i f t he r e l a t i ons hi p be t w e e n a t t e nt i on a nd e m ot i on i s t o be f u l l y e l a bor a t e d. L a s t l y, w hi l e m a ny s t udi e s ha ve f ound t ha t t h r e a t e ni ng s t i m ul i r e s ul t i n g r e a t e r a t t e nt i on t ha n ot he r e m ot i ona l s t i m ul i s om e f i nd m or e a c om pl e x a nd nua nc e d r e l a t i ons hi p. S c hi m m a c k ( 2005 ) w i s he d t o e va l ua t e t hr e e m ode l s of how ne ga t i ve a f f e c t i ve s t i m ul i m i gh t i n f l ue nc e a t t e nt i on. T he f i r s t pos s i bi l i t y he i de nt i f i e s i s c a t e gor i c a l ne ga t i vi t y, i n w hi c h ne ga t i ve s t i m ul i a t t r a c t a t t e nt i on s i m pl y be c a us e i t i s ne ga t i ve N o di s t i nc t i ons a r e m a de be t w e e n de gr e e s of ne ga t i vi t y o r s pe c i f i c t h r e a t c ont e nt A s e c ond pos s i bi l i t y i s t ha t t h r e a t s a r e de t e c t e d m or e r e a di l y be c a us e of s om e e vol ut i ona r y pr e di s pos i t i on. T he t hi r d pos s i bi l i t y he out l i ne s s ugge s t s t ha t a r o us a l a nd not va l e nc e i s t he di m e ns i on unde r l yi ng t he c a pa c i t y of e m ot i ona l i m a ge s t o c a pt ur e a t t e nt i on. I n a s e r i e s of e xpe r i m e nt s i nvol vi ng s ubj e c t s e i t he r s ol vi ng m a t h p r obl e m s or de t e c t i ng ba r s a bove or be l ow a f f e c t i ve i m a ge s S c hi m m a c k f ound t ha t a r o us a l r a t i ngs o f t he i m a ge s pr ovi de d t he be s t e xpl a na t i on of pe r f or m a nc e C om pa r i s ons of a t t e nt i ona l c a pt ur e f or e vol ut i ona r y t hr e a t s ( e g s na ke s ) w i t h ot he r s t i m ul i o f m a t c he d a r ous a l a nd va l e nc e r e ve a l e d no r e l i a bl e di f f e r e nc e A ddi t i ona l l y, c om pa r i s on s w i t hi n ne ga t i ve s t i m ul i di d r e ve a l r e l i a bl e di f f e r e nc e s be t w e e n pe r f or m a nc e l e ve l s a s a f unc t i on o f va l e nc e or de gr e e of ne ga t i vi t y\n18 T he r e l a t i ons hi p be t w e e n e m ot i on a nd a t t e nt i on i s a c om pl e x one I nve s t i ga t i ons m us t c ons i de r w he t he r a t t e nt i on i s c a pt ur e d a nd/ or he l d, pos s i bl e i ndi vi dua l di f f e r e nc e s i n s ubj e c t s a nd w he t he r i m a ge va l e nc e i s c onf ounde d w i t h ot he r r e l e va nt i m a ge pr ope r t i e s A t t e nt i on and P e r c e pt ual L e ar ni ng C e r t a i n t ype s of pe r c e pt ua l l e a r ni ng r e qui r e a t t e nt i on ( W e i s s E de l m a n F a hl e 1993) H ow e ve r t he s pe c i f i c r o l e of a t t e nt i on r e m a i ns a m bi guous T hr e e r a t he r s uc c e s s f ul m ode l s w i l l i l l us t r a t e s om e o f t he c om p e t i ng e xpl a na t i ons of P L O ne pr ope r t y of pe r c e pt ua l l e a r n i ng t ha t ne e ds t o be f u l l y a ddr e s s e d by a ny s uc c e s s f ul m ode l i t s gr e a t s pe c i f i c i t y. T r a i ni ng i n w ha t a r e us ua l l y v e r y di f f i c ul t t a s ks f a i l s t o ge ne r a l i z e t o nove l t a s ks t ha t di f f e r a l ong c e r t a i n di m e ns i ons E a c h of t he f ol l ow i ng m ode l s a t t e m pt s t o a ddr e s s t he s pe c i f i c i t y w i t h a s l i ght l y di f f e r e nt a ppr oa c h. A h i s s a r & H oc hs t e i n s ( 2004) r e ve r s e hi e r a r c hy m ode l f oc us e s on t op do w n a t t e nt i ona l e f f e c t s w i t h a t he or e t i c a l f r a m e w or k g r ounde d i n h i e r a r c hi c a l r e c e pt i ve f i e l d s t r uc t ur e I n c ont r a s t D os he r & L u s pe r c e pt ua l t e m pl a t e m ode l f oc us e s on bot t om up p r oc e s s e s w i t h a f oc us on s pa t i a l vi s i on c ons i de r a t i ons s uc h a s c ha nne l w e i ght i ng ( P e t r ov, D os he r & L u, 2005) W a t a na be & S e i t z s m ode l di m i ni s he s t he r ol e of a t t e nt i on i n pe r c e pt ua l l e a r ni ng, f oc us i ng i ns t e a d on t he ne ur oc he m i c a l pr oc e s s e s w hi c h unde r l i e a t t e nt i on a nd r e i nf o r c e m e nt l e a r ni ng ( S e i t z & W a t a na be 2005) R e v e r s e H i e r a r c hy T he or y T he r e ve r s e hi e r a r c hy t he or y ( R H T ) of pe r c e pt ua l l e a r ni ng s ugge s t s t ha t t op dow n a t t e nt i on i s t he c r i t i c a l e l e m e nt i n i m pr ove m e nt s i n c e r t a i n pe r c e pt ua l t a s ks ( A hi s s a r & H oc hs t e i n 2004; A hi s s a r 1999 ) A dvoc a t e s of t h e R H T m ode l a r gue t ha t a l l t he i nf or m a t i on ne c e s s a r y t o pe r f or m t he pe r c e pt ua l t a s k i n que s t i on i s pr e s e nt i n t he\n19 pe r c e pt ua l s ys t e m a t t r a i ni ng. R a t he r t ha n pr ov i di ng a ddi t i ona l i n f or m a t i on t r a i ni ng a s s i s t s t he pa r t i c i pa nt i n i de nt i f yi ng t a s k r e l e va nt i nf or m a t i on a nd i gnor i ng i r r e l e va nt i nf or m a t i on. A s e c ond ke y a s pe c t of t he m ode l s u gge s t s t ha t a s a pa r t i c i pa nt i s t r a i ne d, t hi s s e a r c h f or di f f e r e nt i a t i ng f e a t ur e s ( i n a di s c r i m i na t i on t a s k, f o r e xa m pl e ) c a s c a de s f r om hi ghe r t o l ow e r f or m s o f r e p r e s e nt a t i on. T hi s vi e w of pe r c e pt i on a s a f unda m e nt a l l y hi e r a r c hi c a l s ys t e m w hi c h s t a r t s w i t h p r i m i t i ve e l e m e nt s l i ke di s c ont i nui t i e s i n t he vi s ua l f i e l d, w hi c h t he n be c om e c ont our s w hi c h t he n be c om e f e a t ur e s w hi c h a r e gr oupe d i nt o obj e c t s w hi c h t he n f o r m s c e ne s i s c e nt r a l t o t he R H T m ode l A hi s s a r a nd H oc hs t e i n s hi e r a r c hi c a l vi e w of vi s ua l pe r c e pt i on f i nds a c onv i nc i ng a na t om i c a l ba s i s i n r e c e pt i ve f i e l d or ga ni z a t i on E vi de nc e r e ga r di ng t he ne t w o r k of r e c e pt i ve f i e l d s i ndi c a t e s t ha t a s vi s ua l s i gna l s a r e pr oc e s s e d, s t a r t i ng w i t h a m or e o r l e s s r e t i not opi c m a p i n V 1 t he y a r e c onve r t e d t o m o r e a nd m o r e a bs t r a c t f o r m s M or e of t he vi s ua l f i e l d i s r e pr e s e nt e d i n a ny gi ve n r e c e pt i ve f i e l d a s t he s e s i gna l s a r e pr oc e s s e d H ow e ve r m o r e c om pl e x s t i m ul us pr ope r t i e s a r e r e qui r e d t o a c t i va t e a gi ve n r e c e pt i ve f i e l d ( e g. l i ne a r i t y or m ot i on) H a vi ng e s t a bl i s he d t ha t t he s e r e c e pt i ve f i e l ds a nd t he pe r c e pt ua l pr oc e s s e s t ha t t he y s uppor t a r e a r r a nge d hi e r a r c hi c a l l y a nd a s s um i n g t ha t l e a r ni ng s t a r t s a t t he hi ghe s t l e ve l of r e pr e s e nt a t i on be f o r e w or ki ng i t s w a y dow n A h i s s a r a nd H oc hs t e i n a s s e r t t ha t pe r c e pt ua l l e a r ni ng i s c ons e r va t i ve w i t h no l e a r ni n g oc c ur r i ng a t a l e ve l l ow e r t ha n i t ne e ds t o. I n t a s ks t ha t p r ovi de hi gh s i gn a l t o noi s e r a t i os ( e g. obj e c t r e c ogni t i on ) pa r t i c i pa nt s di s c r i m i na t i ons r e l y on hi gh l e ve l r e p r e s e nt a t i ons I n s i t ua t i ons w i t h l ow s i gna l t o noi s e r a t i os pa r t i c i pa nt s di s c r i m i na t i ons m us t r e l y on l e s s r e f i ne d r e pr e s e nt a t i ons T he R H T s ugge s t s t ha t l oc a t i on s pe c i f i c i t y i s t he r e s ul t of t he br a i n s e e ki ng t he l e ve l of r e pr e s e nt a t i on w i t h t he be s t s i gna l noi s e t o r a t i o c a s c a di ng dow n t o a\n20 l e ve l w i t h a r e t i not opi c i s om or phi s m a nd t he t r a i n i ng r e m a i ni ng t r a ppe d a t t ha t l e ve l E a s y pe r c e pt ua l t a s ks a r e l e a r ne d a t a hi gh l e ve l l e a di ng t o a l m os t no or i e nt a t i on or l oc a t i on s pe c i f i c i t y. T he l a s t a s s um pt i on of t he i r m ode l i s t ha t P L i s a t t e nt i on dr i ve n, w i t h a t t e nt i on s e l e c t i ng t he a pp r opr i a t e l e ve l of r e p r e s e nt a t i on a nd i nc r e a s i ng i t s w e i ght i n de t e r m i ni ng r e s pons e s P e r c e pt ual T e m pl at e M ode l D os he r & L u ( 1999) pr e s e nt a n a l t e r na t i ve e xpl a na t i on. T he pe r c e pt ua l t e m pl a t e m ode l ( P T M ) pr ovi de s t h r e e pos s i bl e m e c ha ni s m s of P L T h i s qua nt i t a t i ve m ode l s ugge s t s i m pr ove m e nt s i n pe r f or m a nc e i n pe r c e pt u a l t a s ks a r e a c c om pl i s he d vi a s t i m ul us e nha nc e m e nt e xt e r na l noi s e r e duc t i on a nd i n t e r na l noi s e r e duc t i on. S t i m ul us e nha nc e m e nt i s c ha r a c t e r i z e d by i nc r e a s e d s i gna l s t r e ngt h f r om t he r e l e va nt pe r c e pt ua l t e m pl a t e E xt e r na l noi s e e xc l us i on oc c ur s w he n t h e t e m pl a t e i s t une d t o e xc l ude i r r e l e va nt i nf o r m a t i on. I nt e r na l or m ul t i pl i c a t i ve noi s e i s va r i a t i on i n t he pe r c e pt ua l de c i s i on s ys t e m w hos e l e ve l de pe nds on t he m a gni t ude of t he s t i m ul us s i gna l T hi s i s i n c ont r a s t w i t h t he a ddi t i ve noi s e l e ve l w hi c h i s i nd e pe n de nt of t he s i gna l m a gni t ude a nd i s c ont r ol l e d vi a e xt e r na l noi s e e xc l us i on. U s i ng a n e xt e r na l noi s e pa r a di gm i n w hi c h t he s ubj e c t m us t di s c r i m i na t e t he or i e nt a t i on of a ga bo r pa t c h pr e s e nt e d be t w e e n s a ndw i c h noi s e m a s ks r e s e a r c he r s w e r e a bl e t o i nve s t i ga t e e a c h of t he s e pos s i bl e m e c ha ni s m s be c a us e e a c h ha s a c ha r a c t e r i s t i c e f f e c t on t he s i gn a l c ont r a s t e xt e r na l noi s e c ont r a s t t hr e s hol d f unc t i on i n a t w o t hr e s hol d, t w o c r i t e r i on pa r a di gm D os he r & L u c onc l ude t ha t t he i m p r ove m e nt s i n t he i r di s c r i m i na t i on e xpe r i m e nt a r e due t o e xt e r na l noi s e e xc l us i on a nd s t i m ul us e nha nc e m e nt T hos e w ho a dvoc a t e t he P T M a r gue t ha t be c a us e ga i ns i n one pe r c e pt ua l t a s k do not i n t e r f e r e w i t h p e r f or m a nc e i n ot he r s i m i l a r t a s ks i t i s\n21 unl i ke l y t ha t i m p r ove m e nt s r e s ul t f r om c ha nge s i n t he e a r l y vi s ua l c e nt e r s r a t he r c ha nge s a r e l i ke l y t o oc c ur a t a n i nt e r m e di a t e pr oc e s s i ng s t a ge w i t h r e l e va nt c ha nne l s a m pl i f i e d ( s t i m ul us e nha nc e m e nt ) a nd i r r e l e va nt c ha nne l s da m pe ne d ( e xt e r na l noi s e e xc l us i on) T he P T M e xpl a i ns t he m ys t e r y of l oc a t i on s pe c i f i c i t y by s ugge s t i ng t ha t t he r e w e i ght i ng of c ha nne l s m a y i nc l ude t he s e l e c t i on of a r e t i na l l oc a t i on. T he s a m e c a n be a r gue d f or or i e nt a t i on s pe c i f i c i t y. W a t a na be e t a l ( 2001 ) f ound l ow l e ve l pe r c e pt ua l l e a r ni ng w i t hout h i ghe r l e ve l pe r c e pt ua l l e a r ni ng or c ons c i ous a t t e nt i on. T he r e s e a r c he r s pr e s e nt e d pa r t i c i pa nt s w i t h a s t i m ul us a r r a y t ha t c ont a i ne d a r a pi d s e r i a l vi s ua l p r e s e nt a t i on ( R S V P ) t a s k i n t he f or e gr ound a nd m ovi ng do t s i n t he ba c kgr ound. A t t he m om e nt t he t a r ge t w a s pr e s e nt e d i n t he c e nt e r o f t he R S V P po r t i on o f t he s c r e e n, t he m ot i on o f t he dot s w a s m a ni pul a t e d s o t he y m ove d w i t h 10% m ot i on c ohe r e nc e D e s pi t e t he f a c t t ha t a t t e nt i on w a s f oc us e d c e nt r a l l y, t ow a r ds t he c ha l l e ngi ng R S V P t a s k, pa r t i c i pa nt s s how e d i nc r e a s e d m ot i on di s c r i m i na t i on s e ns i t i vi t y i n t he di r e c t i on t ha t w a s pr i m e d by t he m ot i on s t i m ul i i n a s ubs e que nt m ot i on di s c r i m i na t i on t a s k. A hi s s a r a nd H oc hs t e i n a r gue t ha t t he s e e f f e c t s a r e m or e a ki n t o a da pt a t i on t ha n P L how e ve r t hi s i nc r e a s e i n s e ns i t i vi t y w a s m uc h m or e l ong l a s t i ng t ha n m os t a da pt a t i on e f f e c t s C ondi t i oni ng M ode l A m ode l w hi c h a t t e m pt s t o e xpl a i n t he s e s pe c i f i c i t i e s i s pr e s e nt e d by S e i t z & W a t a na be ( 2005) T he a ut hor s s ugge s t t ha t t he c r i t i c a l f a c t or i n de t e r m i ni ng w ha t i s a nd i s not l e a r ne d i n pe r c e pt ua l l e a r ni ng t a s ks i s t e m po r a l pr oxi m i t y. W he n a r e i nf o r c e m e nt s i gna l i s pr ovi de d t o t he s ubj e c t w ha t i s t a s k r e l e v a nt or t a s k i r r e l e va nt c a n be l e a r ne d w i t h e qua l a c c ur a c y. S t udi e s w hi c h f ound a l a c k o f t a s k i r r e l e va nt l e a r ni ng, f a i l e d t o\n22 pr ovi de a ny c ons i s t e nt r e l a t i ons hi p be t w e e n t he t a s k i r r e l e va nt f e a t ur e s a nd t he t a r ge t I n t he pr e vi ous s t udy, t he t a r ge t a l w a ys a ppe a r e d s i m ul t a ne ous l y w i t h a gi ve n m ot i on di r e c t i on. G r oundi ng t he i r a na l ys i s i n t he c ondi t i o ni ng l i t e r a t ur e t he r e s e a r c he r s s ugge s t t ha t t r a di t i ona l r e i nf o r c e m e nt a ppr oa c he s c a n go a l ong w a y t ow a r ds r e s ol vi ng t he s t a bi l i t y pl a s t i c i t y di l e m m a i n vi s ua l pe r c e pt i on. P e r c e pt ua l l e a r ni ng, a nd s i m i l a r i s s ue s r e ga r di ng c ha nge s i n pe r c e pt ua l pe r f or m a nc e a s a f unc t i on o f l e a r n i ng or c ont e xt ha ve be e n gi ve n s hor t s hr i f t be c a us e of t he be l i e f t ha t pe r c e pt ua l s ki l l s a r e ha r d w i r e d a f t e r a c r i t i c a l pe r i od T hi s s e e m s r e a s ona bl e be c a us e i n a t hr e a t f i l l e d w o r l d, s t a bl e pe r c e pt s a l l ow f or r a pi d a nd une qui voc a l pr oc e s s i ng. H ow e ve r t he ba l a nc e be t w e e n s t a bi l i t y a nd pl a s t i c i t y c a n be e f f e c t i ve l y a c c ount e d f or vi a r e i n f or c e m e nt m ode l s W i t hi n t hi s f r a m e w or k, t he a l e r t i ng po r t i on o f t he a t t e nt i o n s ys t e m i s r e s pons i bl e f or t h i s l e a r ni ng. I t i s a c c om pl i s he d vi a t he di f f us e t r a ns m i s s i o n of ne ur om odul a t or y c he m i c a l s s uc h a s a c e t yl c hol i ne or nor e pi ne phr i ne A ddi t i ona l e vi de nc e r e ga r di ng t he r ol e of ne ur om o dul a t or s i n pe r c e pt ua l l e a r ni ng c a n be f ound i n a s t udy by D i ns e e t a l ( 2003 ) R e s e a r c he r s a t t e m pt e d t o m a ni pul a t e s om a t os e n s or y r e pr e s e nt a t i on of a t a c t i l e s t i m ul us vi a a dm i ni s t r a t i on of m e m e nt i ne a nd a m phe t a m i ne M e m e nt i ne bl oc ks N m e t hyl D a s pa r t a t e ( N M D A ) r e c e pt or s w hi c h a r e i m pl i c a t e d i n s yna pt i c pl a s t i c i t y. M uc h s yna pt i c pl a s t i c i t y i s a c c ount e d f or i n t e r m s o f l ong t e r m pot e nt i a t i on a nd de p r e s s i on ( A gr a nof f e t a l 1999) P ot e nt i a t i on o r a r e duc t i on i n t he f i r i ng t h r e s hol d of a ne ur on, i s m e di a t e d i n l a r ge pa r t by N M D A r e c e pt or s A m phe t a m i ne w a s c hos e n t o a c c e l e r a t e l e a r ni ng be c a us e i t a c t i va t e s t he s ym pa t he t i c ne r vous s ys t e m a nd, w i t h i t t he H P A a xi s A f t e r a dm i ni s t r a t i on f or t h r e e hour s pa r t i c i pa nt s w e r e e xpos e d t o a t a c t i l e s t i m ul us on t he t i p of one of t he i r f i nge r s\n23 B ot h of t he s e m a ni pul a t i ons ( a dm i ni s t r a t i on a nd e xpos ur e ) w e r e pl a c e bo c ont r ol l e d S ubj e c t c oul d not vi e w t he i r ha nd. A t t he e nd o f t hr e e hour s a t w o poi nt t hr e s hol d di s c r i m i na t i on w a s a dm i ni s t e r e d t o bot h t he e xpos e d f i nge r a nd a not he r f i nge r T hos e w ho w e r e e xpos e d t o t he a m phe t a m i ne s how e d l o w e r t hr e s hol ds t ha n a n i n i t i a l m e a s ur e on t he s e l e c t e d f i nge r a nd no l e a r ni ng on a not he r f i nge r M or e ove r s om a t os e ns or y e voke d pot e nt i a l s s how e d a gr e a t e r di s t a nc e be t w e e n t he r e pr e s e nt e d poi nt s i n t he s om a t os e n s or y c or t e x i n t he a m phe t a m i ne c ondi t i o n. T he r e w a s no l e a r ni ng i n t he m e m e nt i ne c ondi t i on. H e r e w e s e e a n e xa m pl e of s e ns i t i z a t i on i n pe r c e pt ua l t a s k i n t he a bs e nc e of f e e dba c k, w i t h l e a r n i ng oc c ur r i ng i n on e ne ur oc he m i c a l m i l i e u a nd no l e a r ni ng i n a not he r W hi l e t he f i r s t t w o m ode l s ( R H T a nd P T M ) m a y f oc us di f f e r e nt l y, s om e ha ve s ugge s t e d t ha t bot h t he t op dow n a nd bot t om up a ppr oa c he s a r e t w o s i de s of t he s a m e c oi n ( F a hl e 2005) F a hl e a r gue s t ha t t he s pe c i f i c i t i e s ( l oc a t i on, o r i e nt a t i on, s pa t i a l f r e que nc y, e t c ) a r e l i ke l y t o due t o m odi f i c a t i ons i n e a r l y or i nt e r m e di a t e vi s ua l pr oc e s s i ng c e n t e r s H ow e ve r he c ont i nue s t he s e m odi f i c a t i ons a r e c ont r ol l e d by t op dow n a t t e nt i ona l e f f e c t s I n a s t udy by L i e t a l ( 20 04) r e s e a r c he r s f ound t ha t t he ne ur ona l r e s pons e s of V 1 t o a s t i m ul i s e t de pe nde d on t he pe r c e pt ua l t a s k unde r t a ke n by t he pr i m a t e s ubj e c t s P r i m a t e s w e r e gi ve n a s i ngl e t ype of s t i m ul us t ha t c oul d be e m pl oye d f or e i t he r a bi s e c t i on or a ve r ni e r a c ui t y pe r c e pt ua l l e a r ni ng t a s k. D e pe ndi ng on w hi c h t a s k w a s a s s i gne d i n a pa r t i c ul a r bl oc k t h e r e s pons e pr ope r t i e s of t he r e c e pt i ve f i e l d c or r e s pondi ng t o t he l oc a t i on of t he s t i m ul us c ha nge d. L i a nd c ol l e gue s a r gue t ha t V 1 m a ybe c onc e i ve d of a s a n a da pt i ve pr oc e s s i ng uni t I n f or m a t i on pr oc e s s i ng a na l ys e s r e ve a l e d t ha t ne ur ons c a r r i e d m or e i nf or m a t i on a bout a g i ve n s t i m ul us pr ope r t y\n24 w h e n t ha t a t t r i but e w a s c r i t i c a l f o r t he di s c r i m i na t i on t a s k. S i m i l a r ps yc hophys i c a l r e s ul t s c a n be f ound i n W e i s s e t a l ( 1993) P a r t i c i pa nt s w e r e t r a i ne d t o pe r f o r m a di s c r i m i na t i on t a s k w i t h t w o or t hogona l of f s e t s t i m ul i I n one c ondi t i on pa r t i c i pa nt s w e r e t ol d t o di s c r i m i na t e t he ve r t i c a l o f f s e t s t i m ul i I n t he ot he r pa r t i c i pa nt s w e r e t ol d t o di s c r i m i na t e t he hor i z ont a l of f s e t s t i m ul i A f t e r be i ng t r a i ne d t o c r i t e r i on, i t w a s f ound t ha t t he P L di d not ge ne r a l i z e t o t he or t hogona l l y o r i e nt e d of f s e t s t i m ul us A ppa r e nt l y a t t e nt i on i s i nvol ve d i n w hi c h a s pe c t s of t he s t i m ul us a r r a y a r e r e pr e s e nt e d i n a m or e e l a bor a t e f a s hi on. A ddi t i ona l e vi de nc e r e ga r di ng t he i nt e r pl a y be t w e e n bot t om up a nd t op dow n f a c t or s c a n be f ound i n s t udi e s t ha t m a ni pul a t e d f e e dba c k f or pa r t i c i pa nt s i n P L t a s ks H e r z og & F a hl e ( 1997) pr e s e nt e d pa r t i c i pa nt s w i t h a c ha l l e ngi ng hype r a c ui t y t a s k, t hos e w ho r e c e i ve d f e e dba c k i m pr ove d m or e r a pi dl y t ha n t hos e w ho di d not E ve n t hos e w ho di d not r e c e i ve f e e dba c k s how e d s om e i m pr ove m e nt ove r t he c our s e of t he e xpe r i m e nt I n a s e c ond e xpe r i m e nt F a hl e c ut t he e r r or s i gna l s i n ha l f E a c h pa r t i c i pa nt w a s onl y a w a r e of ha l f of hi s or he r e r r or s how e ve r t hi s f e e dba c k w a s e nough t o put t he i r pe r f or m a nc e on l e ve l w i t h t hos e w ho r e c e i ve d f e e d ba c k f or a l l t he i r e r r o r s F e e dba c k i s e vi de nt l y i m por t a nt f or pe r c e pt ua l l e a r ni ng but no t e s s e nt i a l T h i s r e pr e s e nt s a c ha l l e nge t o r e i nf o r c e m e nt a c c ount s of pe r c e pt ua l l e a r ni ng, i n w hi c h f e e dba c k f i gu r e s qui t e c e nt r a l l y. R e vi e w i ng w ha t w e ha ve c ove r e d s o f a r e m ot i ona l s t i m ul i c a n i nduc e r a pi d phys i ol ogi c a l c ha nge s i n t he br a i n, a s w e l l a s t he r e s t of t he body I t i s pos s i bl e t ha t pr oj e c t i ons f r om t he a m ygda l a t o t he s e ns or y c or t e x unde r l i e t he r obus t e f f e c t s of e m ot i on on vi s ua l a t t e nt i on T h r e a t e ni ng s t i m ul i a r e l i ke l y p r oc e s s e d i n a pr e a t t e nt i ve\n25 m a nne r P e r c e pt ua l l e a r ni ng i s c ha r a c t e r i z e d a s l o ng l a s t i ng c ha nge s i n t he m a nne r i n w hi c h s t i m ul i a r e p r oc e s s e d. T he r a t e a nd na t u r e o f t he s e c ha nge s a r e gove r ne d bot h by a t t e nt i on a nd t a s k s pe c i f i c i t i e s V a l e n c e d S t i m u l i and P L I n a s e n s e P L a nd p r oc e s s i n g of a f f e c t i n g s t i m u l i r e p r e s e n t p ol a r e nds of a c ont i nuu m I m pr ove m e n t s i n p s y c ho p h y s i c a l d i s c r i m i n a t i ons i nvo l v e e xt e ns i v e pr a c t i c e w i t h hi g h l y a r t i f i c i a l s t i m u l i I n c ont r a s t p r oc e s s i n g of e m ot i ona l l y m e a n i n g f u l s t i m u l i i s r a pi d, p r e a t t e n t i ve a nd l i k e l y ha s s om e f i x e d e vo l u t i ona r y ba s i s T he r o l e of t he l i m b i c s y s t e m i n r e g u l a t i n g a u t om a t i c r e s p o n s e s t o va l e n c e d s t i m u l i i s h i g h l y c ons e r ve d i nd i c a t i n g a r e l a t i v e l y s t a bl e r o l e ( K a l a t 1998) T h e b i o l o g i c a l a nd pe r c e p t ua l f un c t i ons g o v e r n e d b y t he s e s t r uc t ur e s a r e f a i r l y r e g u l a r a c r o s s m a m m a l s S t ud yi n g t he i n t e r pl a y be t w e e n t he r a pi d, un l e a r n e d ob l i g a t or y r e s p o n s e s e l i c i t e d w he n s ubj e c t vi e w e m o t i on a l s t i m u l i a nd t he s l ow l e a r n e d a r t i f i c i a l c h a n g e s of P L m a y he l p r e s e a r c h e r s c h a r t t he s p a c e be t w e e n t he s e p ol e s A f f e c t i v e m a n i p ul a t i ons p e r m i t a nov e l m e a ns of i nve s t i g a t i n g t he n a t ur e of a t t e n t i on a nd t a s k s p e c i f i c i t y i n P L i n s o f a r a s t he pr oc e s s i n g of e m o t i on a l l y c h a r g e d s t i m u l i w i l l pe r m i t s t r on g m a n i p ul a t i ons of t he c on d i t i ons unde r w hi c h P L o c c u r s T he bounda r i e s of P L a r e i n c ho a t e I f v a r i e t i e s of P L p e r f or m a n c e w e r e f ound t o i n t e r a c t w i t h p r oc e s s i n g of b i o l o g i c a l l y r e l e v a n t s t i m u l i a s ne a r l y a l l e m o t i on a l s t i m u l i a r e t hi s c ou l d i nf or m t he de b a t e r e g a r d i n g t he l o c us a nd b e s t c ha r a c t e r i z a t i on of P L I t s t a nd s t o r e a s on t ha t i f a P L t a s k c ou l d b e i nf us e d w i t h a f f e c t i v e c ont e n t r e s e a r c h e r s c ou l d m odu l a t e t he r a t e of l e a r n i n g i n t he d i s c r i m i n a t i on. E nh a n c e d p r oc e s s i n g\n26 of a f f e c t i n g i m a g e s a nd w or d s i s a pa t t e r n t ha t e m e r g e s f r o m t he l i t e r a t ur e on e m o t i on a l s t i m u l i a nd pe r c e p t i on ( C om p t o n, 2003) W i t hi n t he r e a l m of e m ot i ona l s t i m u l i n e g a t i v e or t hr e a t r e l a t e d i m a g e s a r e g r a n t e d pe r c e p t ua l p r i or i t y I f p r oc e s s i n g i s p r e d i s p o s e d or b i a s e d t o w a r d s e m ot i ona l s t i m u l i t he e m ot i ona l pr o pe r t i e s of a P L s t i m u l us or c ont e xt c ou l d b e m a n i p ul a t e d t o c on t r ol r a t e of l e a r n i n g E m ot i ona l l y s a l i e nt s t i m u l i c ou l d b e i nt e g r a t e d i n t o s t a nda r d P L pa r a d i g m s i n a t l e a s t t w o w a y s T he e m ot i ona l c on t e n t c ou l d b e a s s oc i a t e d t he P L t a s k i n t i m e I n t hi s c a s e a d i s c r i m i n a t i on c ou l d b e e i t he r pr e c e d e d or s uc c e e d e d b y va l e n c e d s t i m u l i A l t e r na t i v e l y, t he e m o t i on a l c ont e n t c oul d b e a s s o c i a t e d w i t h t he P L t a s k i n s p a c e W i t hi n t hi s a p p r oa c h a f f e c t i n g i m a g e s a r e i n t e g r a l t o t he l e a r n e d d i s c r i m i n a t i on. T he f o l l ow i n g t hr e e e xpe r i m e nt s e xpl or e d t he f i r s t of t h e s e p o s s i bi l i t i e s\n27 C ha p t e r T w o P i l o t E x p e r i m e n t 1 T he i nf l u e n c e of v a l e n c e d i m a g e s on pe r c e p t ua l l e a r n i n g of v e r n i e r s t i m u l i P r i m i n g s ub j e c t s w i t h a f f e c t i ve i m a g e s w i l l l i k e l y i m pa c t t he r a t e of l e a r n i n g i n a p s y c ho p h y s i c a l j ud g m e n t G i v e n t he s c he du l i n g c on s t r a i n t s of unde r g r a du a t e p a r t i c i pa n t s a P L pa r a d i g m t ha t r e s ul t e d i n r a pi d g a i ns w a s p r e f e r a b l e V e r n i e r a c u i t y d i s c r i m i n a t i ons c a n b e qu i c k l y l e a r n e d ( F a h l e e t a l 1995) a nd w a s s e l e c t e d t o p r ovi d e a s e n s i t i ve d i s c r i m i n a t i on a g a i ns t w hi c h t o c h a r t s ubj e c t s p r o g r e s s A c u i t y t a s k s i nvo l v e s ubj e c t s m a k i n g a f i n e s p a t i a l d i s c r i m i n a t i on a nd h a ve b e e n s ho w n t o be h i g h l y l e a r n a b l e L e a r n i n g i s r e t i no t o pi c ( F a h l e 2005) s o a s ubj e c t m us t m a i n t a i n f i x a t i on on e a c h t r i a l I t w a s h y p o t he s i z e d t ha t t he r a pi dl y p r e s e n t e d t hr e a t r e l a t e d p r i m e a c t i va t e s a n a d a p t i ve e m ot i ona l r e s p o n s e w i t hi n s ubj e c t s T he s e r a pi d or i e nt i n g r e s p o n s e s w i l l f a c i l i t a t e l e a r n i n g i n t he d i s c r i m i n a t i on i m m e d i a t e l y f o l l ow i n g t he n e g a t i v e l y va l e n c e d p r i m e I n or d e r t o p u t t he h y p o t he s i s t o a s t r on g t e s t i m a g e s s e l e c t e d f o r t he t w o c ond i t i ons f r om t he I A P S ( L a n g B r a d l e y & C u t hb e r t 2005) w e r e a p p r o x i m a t e l y m a t c h e d f o r a r ous a l I m a g e s f o r t he ne g a t i v e l y va l e n c e d c on d i t i on w e r e a l l s e l e c t e d f or t he i r t hr e a t c ont e n t ( e g s na r l i n g do g m a n w / g u n s na k e ) w he r e a s i m a g e s s e l e c t e d f or t he c on t r ol c ond i t i on w e r e p o s i t i ve i n v a l a n c e a nd s e l e c t e d t o be s t i m u l a t i n g but no t t h r e a t e n i n g ( e g m oun t a i n c l i m b i n g w i nds ur f i n g e t c ) M e t hod: Subj e c t s 56 s ubj e c t s ( 40 F e m a l e 16 M a l e ) w e r e r e c r ui t e d f r o m U ni ve r s i t y o f S out h F l or i da unde r gr a dua t e c l a s s e s\n28 M at e r i al s : T he e xpe r i m e nt w a s c onduc t e d us i ng a n A ppl e G 4 c om put e r r unni ng a n e xpe r i m e nt a l pr og r a m c r e a t e d w i t h R e a l B a s i c A s c a n be s e e n i n f i gur e 1, t he a c ui t y s t i m ul us c ons i s t e d of t w o l i ne s t he bot t om of w hi c h w a s of f s e t t o e i t he r t he r i ght or t he l e f t T he m a gni t ude of t he o f f s e t r a nge d be t w e e n 032 49 a r c ( 1 t o 15 pi x e l s ) 60 t hr e a t e ni ng a nd 60 pos i t i ve l y va l e nc e d, a r ous i ng p r i m e s w e r e s e l e c t e d f r om t he I nt e r na t i ona l A f f e c t i ve P i c t ur e S ys t e m ( L a ng, B r a dl e y, & C ut hbe r t 2005) T he m e a n va l e nc e r a t i ng f or i m a ge s i n t he ne ga t i ve c ondi t i on w a s 3. 83 ( SD = 90 ) T he m e a n va l e nc e r a t i ng f or i m a ge s i n t he pos i t i ve c ondi t i on w a s 7. 24 ( SD = 63 ) T he a ve r a ge a r ous a l s c or e f or ne ga t i ve i m a ge s w a s 5. 74 ( SD = 71) T he a ve r a ge a r ous a l s c or e f o r pos i t i ve i m a ge s w a s 4. 92 ( SD = 1 03) P r oc e dur e : A f t e r a n i ni t i a l c a l i br a t i on pe r i od l a s t i ng 30 t r i a l s dur i ng w hi c h t he m a gni t ude of t he of f s e t w a s va r i e d pa r t i c i pa nt s c om pl e t e d 12 bl oc ks of 10 t r i a l s E a c h pa r t i c i pa nt w a s pr e s e nt e d w i t h a ve r ni e r a c ui t y t a s k i n one o f f our c o r ne r l oc a t i ons on a c om put e r m oni t or F or a ny s ubj e c t t h e of f s e t w a s pr e s e nt e d i n t he s a m e c or ne r on a l l t r i a l s A s c a n be s e e n i n f i gur e 1 i n a ddi t i on t o t he ve r ni e r s t i m ul us p r e s e nt e d pe r i phe r a l l y, t he r e w a s a 5 o r S p r e s e nt e d s i m ul t a ne ous l y i n t he c e nt e r o f t he s c r e e n. P a r t i c i pa nt s w e r e pr om pt e d t o i n d i c a t e t he di r e c t i on of t he of f s e t a nd t he n pr om pt e d t o i ndi c a t e t he i de nt i t y o f t he c ha r a c t e r pr e s e nt e d c e nt r a l l y. T he m a gni t ude of t he o f f s e t w a s a dj us t e d t o a l e ve l w he r e s ubj e c t s w e r e a ppr oxi m a t e l y 75% a c c ur a t e T he s e que nc e of s t i m ul i dur i ng t he c a l i br a t i on s t a ge i s i l l us t r a t e d i n f i gur e 2. E a c h t r i a l be ga n w i t h a f i xa t i on s t i m ul us p r e s e nt e d i n t he c e nt e r of t he s c r e e n. I m m e di a t e l y f ol l ow i ng t he f i xa t i on, t he t a r ge t s t i m ul us w a s pr e s e nt e d. N e xt pa r t i c i pa nt s w e r e pr om pt e d t o i ndi c a t e w he t he r t he of f s e t w a s t o t he r i gh t or t he l e f t O n a l l t r i a l s a ny\n29 of f s e t e r r or s w e r e i ndi c a t e d w i t h a buz z e r F e e dba c k w a s onl y pr ovi de d r e ga r di ng t he of f s e t t a s k. E a c h t r i a l c onc l ude s w i t h t he s ubj e c t i ndi c a t i ng w he t he r t he c e nt r a l l y pr e s e nt e d c ha r a c t e r w a s a 5 or a n S T he c e nt r a l f i xa t i on t a s k i nc r e a s e d t he l i ke l i hood t ha t t he of f s e t s t i m ul us w i l l r e m a i n a t a c ons t a nt l oc a t i on i n t he pa r t i c i pa nt s vi s ua l f i e l d. A ddi t i ona l l y pe r f or m a nc e i s a t c e i l i n g w he n t he a c ui t y s t i m ul us i s f ove a t e d, s o pe r i phe r a l pr e s e nt a t i on l e a ve s r oom f or i m pr ove m e nt s P a r t i c i pa nt s w e r e pr e s e nt e d w i t h t r i a l s i n e i t he r o f t w o c ondi t i ons I n t he t hr e a t c ondi t i on, pa r t i c i pa nt s w e r e pr e s e nt e d w i t h a t hr e a t e ni ng i m a ge 500m s pr i o r t o t he t a r ge t I n t he non t hr e a t c ondi t i on, pa r t i c i pa nt s w e r e p r e s e nt e d w i t h a pos i t i ve l y va l e nc e d i m a ge f or 500m s p r i or t o e a c h t a r ge t B e c a us e of t he l i m i t e d num be r o f t h r e a t r e l a t e d i m a ge s i n t he I A P S t he 60 s a m pl e d i m a ge s i n e a c h va l e nc e c a t e gor y w e r e pr e s e nt e d t w i c e e a c h. H ow e ve r t he o r de r o f t he i m a g e s w a s c om pl e t e l y r a ndom i z e d s o t ha t one i m a ge c oul d a ppe a r t w o t i m e s be f o r e a not he r i m a ge w a s pr e s e nt e d e ve n onc e I t w a s hope d t ha t t h i s pr e s e nt a t i on or de r w oul d m i ni m i z e a ny a da pt a t i on e f f e c t s T he s e que nc e of s t i m ul i i n t he t hr e a t pr i m e d P L t a s k i s i l l us t r a t e d i n f i gur e 3. T he s e que nc e w a s i de nt i c a l t o t he a dj us t m e nt s t a ge s e que nc e but c ont a i ne d a t hr e a t e ni ng o r non t hr e a t e ni ng pr i m e f ol l ow i ng t he f i xa t i on. I t w a s hypot he s i z e d t ha t pa r t i c i pa nt s i n t he t hr e a t c ondi t i on w oul d l e a r n t he di s c r i m i na t i on t a s k f a s t e r t ha n t hos e i n t he ne ut r a l c ondi t i on. R e s ul t s : D ue t o hi gh va r i a bi l i t y i n pe r f or m a nc e l e ve l s a nd r a t e s of i m pr ove m e nt obs e r va t i ons f r om t he f i r s t a nd s e c ond ha l ve s of t h e P L e xpe r i m e nt w e r e c om b i ne d i nt o t w o l a r ge bl oc ks i n or de r t o s t a bi l i z e m e a ns A l l s ubs e que nt a na l ys e s w i l l t r e a t l e a r n i ng\n30 a s t he a ve r a ge pe r f or m a nc e i n t he s e c ond bl oc k m i nus t he a ve r a ge pe r f or m a nc e i n t he f i r s t bl oc k. T he pe r c e nt a ge of t r i a l s i n w hi c h s ubj e c t s f a i l e d t o r e por t t he i de nt i t y o f t he c e nt r a l c ha r a c t e r f o r a l l t r i a l s c a n be s e e n i n f i gur e 4. A ny t r i a l s i n w hi c h t he s ubj e c t s di d not c or r e c t l y i ndi c a t e t he c e nt r a l c ha r a c t e r w e r e e x c l ude d f r om s ubs e que nt a na l ys e s I n or de r t o c he c k t ha t e r r or s di d not va r y a s a f unc t i o n of p r i m e a n A N O V A w a s c onduc t e d w i t h pr i m e ( pos i t i ve ne ga t i ve ) a s t he be t w e e n s ubj e c t s f a c t or a nd bl oc k ( 1, 2) a s t he w i t hi n s ubj e c t s f a c t or T he r e w e r e no r e l i a bl e e f f e c t s on e r r or s ( bl oc k, F ( 1, 54) = 1 562, M S e = 007, p = 23; pr i m e F ( 1 54) = 532 M S e = 02, p = 51; b l oc k x p r i m e F ( 1, 54) = 133, p = 76) R a t e of l e a r ni ng w a s m e a s ur e d i n t hi s e xpe r i m e nt by s ubt r a c t i ng e a c h s ubj e c t s a c c ur a c y l e ve l i n t he f i r s t ha l f of t he e xpe r i m e nt f r om s ubj e c t s pe r f or m a nc e i n t he s e c ond ha l f of t he e xpe r i m e nt F i gur e 5 s how s t he di f f e r e nt a m ount s o f l e a r ni ng S ubj e c t s i n t he t h r e a t pr i m e d c ondi t i on ( M = 07 S D = 081 ) l e a r ne d m or e t ha n s ubj e c t s i n t he pos i t i ve l y p r i m e d c ondi t i on ( M = 029 S D = 071) t ( 54) = 2 03, p = 048 D i s c us s i on A s a nt i c i pa t e d, s ubj e c t s pe r f or m a nc e i n t he ne ga t i ve l y pr i m e d c ondi t i on w a s s upe r i or t o s ubj e c t s pe r f or m a nc e i n t he pos i t i ve l y pr i m e d c ondi t i on T hi s i s e vi de nc e t ha t P L pe r f or m a nc e m a ybe i n f l ue nc e d by a f f e c t i ve i m a ge s H ow e ve r s e ve r a l qua l i f i c a t i ons a r e i n o r de r T hi s m e a s ur e of l e a r ni ng c om pa r i ng pe r f o r m a nc e i n t he f i r s t a nd s e c ond ha l ve s of t he e xpe r i m e nt i s ve r y c oa r s e I n t hi s c a s e i t w a s onl y ut i l i z e d be c a us e s ubj e c t s pe r f or m a nc e s w e r e qui t e noi s y\n31 A ddi t i ona l l y, w hi l e t he a r ous a l l e ve l of t he i m a ge s w a s a ppr oxi m a t e l y m a t c he d be t w e e n c ondi t i ons i t w a s not e xa c t l y s o. L a s t l y i t w a s t he c ondi t i on w i t h s upe r i or a c c ur a c y, t he t hr e a t c ondi t i on, t ha t ha d t he hi ghe r m e a n a r ous a l r a t i ng. T hi s c onf ound w i l l ne e d t o be a ddr e s s e d i n f ut ur e r e s e a r c h. I t i s unf o r t una t e t ha t t he s ubj e c t s pe r f o r m a nc e l e v e l s i n t hi s di s c r i m i na t i on t a s k w e r e s o va r i a bl e T h i s c oul d be due t o a num be r o f f a c t or s F i r s t t he num be r of t r i a l s m a y be t oo l ow S ubj e c t s onl y c om pl e t e d t he p r i m e d di s c r i m i na t i on t a s k on 120 t r i a l s I n c ont r a s t s ubj e c t s i n t he s t udy by P he l ps e t a l ( 2 006) c om pl e t e d 10 bl oc ks of 120 t r i a l s M or e obs e r va t i ons m a y be ne e de d. W hi l e p e r c e pt ua l l e a r ni ng ha s be e n s how n t o de ve l op ove r s hor t pe r i ods of t i m e t ypi c a l l y e xpe r i m e nt s t a ke s e ve r a l hour s f or a ny i ndi vi dua l s ubj e c t S e c ond, i ns t r uc t i ons m a y not h a ve be e n s uf f i c i e nt l y e xpl i c i t S ubj e c t s s e e m t o ha ve ha d di f f i c ul t y m a i nt a i ni ng f i xa t i on i n t he e xpe r i m e nt W hi l e t he num be r of m i s s e d f i xa t i ons di d not va r y a s a f unc t i on of bl oc k or p r i m e t he num be r of e r r o r s w a s hi gh. L a s t l y, t he pos i t i ve i m a ge s w e r e qui t e a r ous i ng. I n a n e f f o r t t o put t he t hr e a t pr i m i ng hypot he s i s t o i t s s t r onge s t t e s t i m a ge s w e r e s e l e c t e d f or t he pos i t i ve c ondi t i on t ha t ha d hi gh a r ous a l r a t i ngs ( e g. w i nds ur f i ng t e e ns on be a c h, s kydi vi ng) U t i l i z i ng ne ut r a l i m a ge s a s c ont r ol s w o ul d l i ke l y ha ve yi e l d e d l a r ge r e f f e c t s P i l ot E x pe r i m e nt 2 T hi s s t udy a t t e m pt e d t o r e s ol ve c e r t a i n de f i c i e nc i e s i n t he pr e vi ous de s i gn by a ddi ng a ne ut r a l l y va l e nc e d c ont r ol c ondi t i on, i nc r e a s i ng t h e s a m pl e a nd i nc r e a s i ng t he num be r o f t r i a l s ove r w hi c h l e a r ni ng i s a s s e s s e d. M e t hod\n32 Subj e c t s : 69 ( 39 F e m a l e 30 M a l e ) s ubj e c t s w e r e r e c r ui t e d f r om U ni ve r s i t y o f S out h F l or i da unde r gr a dua t e c l a s s e s M at e r i al s : T he P L s t i m ul i e m pl oye d a nd p r ogr a m us e d t o ga t he r da t a w e r e i de nt i c a l t o t hos e us e d i n t he pr e vi o us s t udy. 100 ne ga t i ve l y va l e nc e d, 100 pos i t i ve l y va l e nc e d, a nd 100 ne ut r a l l y va l e nc e d pr i m e s w e r e s e l e c t e d f r om t he I nt e r na t i ona l A f f e c t i ve P i c t ur e S ys t e m ( L a ng, B r a dl e y, & C ut hb e r t 2005 ) T he m e a n va l e nc e r a t i ng f or i m a ge s i n t he ne ga t i ve c ondi t i on w a s 3. 22 ( SD = 1. 0 ) T he m e a n va l e nc e r a t i ng f o r i m a ge s i n t he pos i t i ve c ondi t i on w a s 7. 19 ( SD = 7 5) T he m e a n va l e nc e r a t i ng f o r i m a ge s i n t he ne ut r a l c ondi t i on w a s 4 99 ( SD = 25) T he a ve r a ge a r ous a l s c or e f or ne ga t i ve i m a ge s w a s 5. 88 ( SD = 70 ) T he a ve r a ge a r ous a l s c or e f or pos i t i ve i m a ge s w a s 5. 76 ( SD = 78 ) T he a ve r a ge a r ous a l s c or e f or t he ne ut r a l c ondi t i on w a s 3. 44 ( S D = 91 ) [ I c oul d s um m a r i z e l a s t 6 s e nt e nc e s i n 1 t a bl e ] P r oc e dur e : P r oc e dur e s w e r e t he s a m e i n t hi s e xp e r i m e nt a s i n t he pr i o r w i t h t he e xc e pt i on of t he nu m be r o f t r i a l s W he r e a s i n t he pr e vi ous e xpe r i m e nt s ubj e c t s c om pl e t e d 150 t ot a l t r i a l s ( 120 t e s t t r i a l s ) i n t hi s e xpe r i m e nt s ubj e c t s c om pl e t e d 350 t ot a l t r i a l s ( 300 t e s t t r i a l s ) T he di s t a nc e be t w e e n t he e ndpoi nt s of t h e ve r ni e r s t i m ul i w e r e a dj us t e d ove r t he i n i t i a l 50 t r i a l s A s w i t h t he pr e vi ous e xpe r i m e nt s ubj e c t s w e r e i ns t r uc t e d t o r e po r t bot h t he di r e c t i on of t he o f f s e t a nd t he c e nt r a l l y p r e s e nt e d c ha r a c t e r T he m a gni t ude o f t he of f s e t w a s a dj us t e d t o a l e ve l w he r e s ubj e c t s w e r e a ppr oxi m a t e l y 75% a c c ur a t e R e s ul t s D e s pi t e a dj us t m e nt s t he r e w e r e di f f e r e nc e s i n ba s e l i ne a c c ur a c y be t w e e n t he ne ga t i ve ( M = 76 ) pos i t i ve ( M = 80 ) a nd ne ut r a l ( M = 80) c ondi t i ons B e c a us e of t hi s\n33 a m ount of l e a r n i ng w a s a s s e s s e d f o r e a c h s ubj e c t b y s ubt r a c t i ng a c c ur a c y i n a gi ve n pr i m e d bl oc k f r om pe r f or m a nc e i n t he i ni t i a l unp r i m e d bl oc k. F i gu r e 6 s how s t he pe r c e nt a ge of m i s s e d f i xa t i ons f o r e a c h c ondi t i on a c r os s t he 6 pr i m e d bl oc ks T he r e w e r e no r e l i a bl e e f f e c t s on e r r o r s ( bl oc k F ( 5, 330 ) = 1. 1 9, M S e = 006, p = 17; pr i m e F ( 2 66) = 2. 58, M S e = 126 p = 42 ; bl oc k x p r i m e F ( 2, 66) = 1. 68 p = 63 ) F i gur e 7 s how s nor m a l i z e d l e a r ni ng a c r os s bl oc ks T he r e w a s no r e l i a bl e e f f e c t of pr i m e on l e a r ni ng F ( 2, 66 ) = 564 M S e = 128, p = 564. T he r e w a s a n e f f e c t o f bl oc k, F ( 5, 330) = 8. 854 M S e = 004, p < 001 A s a nt i c i pa t e d, t he r e w a s a r e l i a bl e bl oc k x pr i m e i nt e r a c t i on s uc h t ha t s ubj e c t s i n t he ne ga t i ve c ondi t i on e nde d w i t h a pe r f o r m a nc e l e ve l t ha t w a s r e l i a bl y hi ghe r t ha n e i t he r t he pos i t i ve o r ne ut r a l c ondi t i ons F ( 10, 330) = 1. 912 p = 043. D i s c us s i on A s w oul d be e xpe c t e d gi ve n t he r e s ul t s of pi l ot e x pe r i m e nt 1, s ubj e c t s i n t he ne ga t i ve pr i m e c ondi t i on s how e d hi ghe r r a t e s of l e a r ni ng t ha n s ubj e c t s i n e i t he r t he ne ut r a l or pos i t i ve c ondi t i ons H ow e ve r i t s houl d be a c know l e dge d t ha t s ubt r a c t i ng i ni t i a l pe r f o r m a nc e f r o m pe r f or m a nc e i n a gi ve n bl oc k m i ght r e s ul t i n be t w e e n g r oup di f f e r e nc e s f r om s our c e s ot he r t ha n t he pr i m e s I t m a y be e a s i e r f or s ubj e c t s t o i m pr o ve f r om a l ow l e ve l o f pe r f or m a nc e t ha n i t i s w he n t h e y pe r f or m a t a hi ghe r l e ve l I f t hi s w e r e t he c a s e t he ga i ns s how n by s ubj e c t s i n t he n e ga t i ve c ondi t i on c oul d ha ve r e s ul t e d f r om t he i r ove r a l l l ow e r ba s e l i ne pr e p r i m e pe r f or m a nc e l e ve l T he ne xt e xpe r i m e nt a t t e m pt e d t o br i ng s ubj e c t pe r f o r m a nc e t o c om pa r a bl e l e ve l s be t w e e n c ondi t i ons by i nc r e a s i ng t he num be r o f t r i a l s s o t ha t t he c or r e c t i v e s a ppl i e d i n t hi s a na l ys i s w i l l be unne c e s s a r y.\n34 C ha pt e r T hr e e E xpe r i m e nt T hi s e xpe r i m e nt w a s s i m i l a r t o t he s e c ond pi l ot e x pe r i m e nt but i nc l ude d 620 t r i a l s i ns t e a d of 350 A ddi t i ona l l y t hi s e xpe r i m e nt pr ovi de d f e e dba c k t o s ubj e c t s a t t he e nd of t he c a l i br a t i on pe r i od r e ga r d i ng t he n um be r of f i xa t i ons w hi c h t he y r e po r t e d i nc or r e c t l y. M e t hod: Subj e c t s 48 s ubj e c t s w e r e r e c r ui t e d f r om U ni ve r s i t y of S out h F l o r i da unde r gr a dua t e c l a s s e s A l l s ubj e c t ha d nor m a l or c or r e c t e d t o nor m a l vi s i on. M at e r i al s : T he p r i m e s t i m ul i P L s t i m ul i a nd da t a ga t he r i ng pr ogr a m w e r e t he s a m e i n t hi s e xpe r i m e nt a s t he s e c ond pi l o t e xpe r i m e nt P r oc e dur e : A f t e r a n i ni t i a l c a l i br a t i on pe r i od l a s t i ng 60 t r i a l s dur i ng w hi c h t he m a gni t ude of t he of f s e t w a s va r i e d pa r t i c i pa nt s c om pl e t e d 10 bl oc ks of 50 p r i m e d t r i a l s f ol l ow e d by one unpr i m e d bl oc k of 60 t r i a l s A ddi t i ona l l y, w he n t he s ubj e c t s c om pl e t e d ha l f of t he pr i m e d t r i a l s t he y w e r e gi ve n a 5 m i nut e br e a k w hi c h t he y w e r e r e qui r e d t o ut i l i z e T he di s t a nc e be t w e e n t he e ndpoi nt s of t he t w o of f s e t l i ne s w a s a dj us t e d dur i ng t he i ni t i a l 60 t r i a l c a l i b r a t i on s t a ge a s w i t h t he p r e vi ou s e xpe r i m e nt s W he n t he c a l i br a t i on pe r i od e nde d, s ubj e c t s w e r e i n f or m e d a s t o pe r c e nt a ge of t r i a l s i n w hi c h t he f i xa t i on w a s m i s s e d a nd e nc our a ge d t o m a i nt a i n f i xa t i on. P a r t i c i pa nt s w e r e pr e s e nt e d w i t h t r i a l s i n one of t hr e e c ondi t i ons P a r t i c i pa nt s vi e w e d e i t he r ne ga t i ve pos i t i ve o r ne ut r a l i m a ge s f or 500 m s pr i o r t o t he t a r ge t\n35 B e c a us e of t he l i m i t e d num be r of t hr e a t r e l a t e d i m a ge s i n t he I A P S t he 100 s a m pl e d i m a ge s i n e a c h va l e nc e c a t e gor y w e r e pr e s e nt e d 5 t i m e s e a c h. H ow e ve r t he o r de r o f t he i m a ge s w a s c om pl e t e l y r a ndom i z e d s o t ha t one i m a ge c oul d a ppe a r m ul t i pl e t i m e s be f or e a not he r i m a ge w a s pr e s e nt e d onc e I t w a s hope d t ha t t hi s pr e s e nt a t i on or de r w oul d m i ni m i z e a ny a da pt a t i on o r f a m i l i a r i t y e f f e c t s R e s ul t s : D a t a f or f our s ubj e c t s w a s t hr ow n out be c a us e t he y m i s s e d m or e t ha n 40 % o f t he c e nt r a l l y pr e s e nt e d c ha r a c t e r s A na l ys e s w e r e c onduc t e d bot h i nc l udi ng a nd e xc l udi ng t he s e s ubj e c t s a nd, w hi l e i t di d not c ha nge t he r e l i a bi l i t y of a ny of t he s pe c i f i c s t a t i s t i c a l t e s t s t he f ol l ow i ng a na l y s i s e xc l ude s t hos e s ubj e c t s be c a us e t he y w e r e c l e a r i ng m a ki ng a t r a de of f be t w e e n r e por t i ng t he c e nt r a l c ha r a c t e r a n d di r e c t i on o f t he of f s e t A gr a ph of t he pe r c e nt a ge of t r i a l s i n w hi c h s ubj e c t s f a i l e d t o r e por t t he i de nt i t y of t he c e nt r a l c ha r a c t e r f or a l l t r i a l s c a n be s e e n i n f i gur e 8. A ny t r i a l s i n w hi c h t he s ubj e c t s di d not c or r e c t l y i ndi c a t e t he c e nt r a l c ha r a c t e r w e r e e xc l ude d f r om s ubs e que nt a na l ys e s I n or de r t o c he c k t ha t e r r or s di d not va r y a s a f unc t i on of p r i m e a n A N O V A w a s c onduc t e d w i t h p r i m e ( pos i t i ve ne ga t i ve ne ut r a l ) a s t he be t w e e n s ubj e c t s f a c t or a nd bl oc k ( 12 l e ve l s ) a s t he w i t hi n s ubj e c t s f a c t or W h i l e t he r e w e r e no r e l i a bl e e f f e c t s on e r r or s ( bl oc k F ( 11 495) = 781, M S e = 008, p = 6 6; pr i m e F ( 2, 45 ) = 2. 40 M S e = 177, p = 10; bl oc k x pr i m e F ( 22 495) = 1. 26 p = 193) t he e f f e c t of pr i m e a ppr oa c he d r e l i a bi l i t y. S ubj e c t s s e e m t o m i s s m or e o f t he f i xa t i ons w he n pr e s e nt e d w i t h t he va l e nc e d pr i m e s A ny t r a de of f be t w e e n a c c ur a c y i n t he of f s e t t a s k a nd t he f i xa t i on r e p r e s e nt s a s e r i ous pr obl e m w he n l e a r ni ng m e a s ur e d a s c ondi t i ona l a c c ur a c y i n t he of f s e t t a s k. I f a s ubj e c t w e r e t o f i xa t e t he of f s e t a nd gue s s w i t h r e s pe c t t o t he c e nt r a l c ha r a c t e r t he y\n36 w oul d a ppe a r a c c ur a t e i n t ha t t r i a l s i n w hi c h t he i d e nt i t y of t he c ha r a c t e r i s r e por t e d i na c c ur a t e l y w e r e e xc l ude d. F i gur e 9 de pi c t s a c c ur a c y f or t r i a l s i n w hi c h s ubj e c t s a c c ur a t e l y i de nt i f i e d t he c e nt r a l l y pr e s e nt e d c ha r a c t e r A n A N O V A w i t h pr i m e ( pos i t i ve ne ga t i ve ne ut r a l ) a s t he be t w e e n s ubj e c t s f a c t or a nd bl oc k ( 12 l e ve l s ) a s t h e w i t hi n s ubj e c t s f a c t or r e ve a l e d a r e l i a bl e e f f e c t o f bl oc k F ( 11, 495) = 4 12, M S e = 007, p = 002 A n e f f e c t of pr i m e F ( 2, 45 ) < 1, or a bl oc k x pr i m e i nt e r a c t i on F ( 22 495) < 1 f a i l e d t o ob t a i n. I n or de r t o m or e f ul l y e xpl o r e t he pos s i bi l i t y o f a t r a de of f i n pe r f or m a nc e be t w e e n c e nt r a l c ha r a c t e r t a s k a nd o f f s e t t a s k, s ubj e c t s w e r e e xc l ude d f r om t he a na l ys i s i n o r de r t o c ont r ol f o r t he num be r o f m i s s e d f i xa t i ons be t w e e n c ondi t i ons T hi s i nvo l ve d t he r e m ova l of obs e r va t i ons f or t hr e e s ubj e c t s i n t he n e ga t i ve c ondi t i on a nd t w o s ubj e c t s i n t he pos i t i ve c ondi t i on. W i t hout t hos e s ubj e c t s t he ove r a l l num be r of m i s s e d f i xa t i ons w a s c om pa r a bl e be t w e e n t he pos i t i ve ( M = 104) ne ga t i ve ( M = 104 ) a nd ne ut r a l ( M = 100) c ondi t i ons A gr a ph of m i s s e d f i xa t i ons onc e t he gr oups w e r e t r i m m e d t o e qua l i z e pe r f or m a nc e c a n be s e e n i n f i gur e 10. A gr a ph o f of f s e t l e a r ni ng f or t he r e m a i ni ng s ubj e c t s c a n be i n s e e n i n f i gu r e 11. W hi l e a ny c o nc l us i ons w oul d be s us pe c t be c a us e of t he vi ol a t i on o f t he i nde pe nde nc e a s s um pt i on of a s e c ond A N O V A w a s r un w i t h s a m e f a c t or s a s t he pr e vi ous f o r t he s a ke of t ho r oughne s s T hi s A N O V A us e d t he f i xa t i on e qua l i z e d da t a s e t T he r e w a s s t i l l a n e f f e c t o f bl o c k, F ( 11, 440) = 3. 07 p = 001. T he r e w a s no e f f e c t of pr i m e F ( 2 40) < 1 o r a bl oc k x p r i m e i nt e r a c t i on F ( 22, 440) < 1\n37 C ha pt e r F our D i s c us s i on W hi l e s ubj e c t s m e a n pe r f or m a nc e a c r os s bl oc ks w a s hi ghe r i n t he ne ga t i ve l y va l e nc e d c ondi t i on t ha n t he pos i t i ve l y va l e nc e d c ondi t i on, c ons i de r a bl e va r i a bi l i t y i n i ndi vi dua l pe r f o r m a nc e l e ve l s pr e ve nt a ny c onc l us i ons r e ga r di ng t he c ont r i but i on of t he a f f e c t i ve c ont e nt t o a c c ur a c y. T h i s s t a nds i n c ont r a s t t o a s t udy c om pl e t e d r e c e nt l y i n w hi c h s ubj e c t s l e a r ni ng of t he s a m e di s c r i m i na t i o n w a s i nf l ue nc e d by va l e nc e d pr i m e s I t i s unf o r t una t e t ha t t he s ubj e c t s pe r f o r m a nc e l e v e l s i n t hi s di s c r i m i na t i on t a s k w e r e s o va r i a bl e T he num be r of t r i a l s m a y s t i l l be t oo l ow T hi s s t udy w a s de s i gne d t o ha ve t w i c e a s m a ny t r i a l s a s t he l onge s t pr e vi ous e xpe r i m e nt us i ng t hi s pa r a di gm bu t t ha t doe s not gua r a nt e e e nough obs e r va t i ons T he num be r of t hr e a t e ni ng i m a ge s us e d i n t he s t udy w a s l i m i t e d t o t hos e s a m pl e d f r om t he I A P S S ubj e c t s onl y c om pl e t e d t he p r i m e d di s c r i m i na t i on t a s k on 500 t r i a l s I n c ont r a s t s ubj e c t s i n t h e s t udy by P he l ps e t a l ( 2006 ) c om pl e t e d 10 bl oc ks of 120 t r i a l s M or e obs e r va t i ons m a y be ne e de d. W hi l e pe r c e pt ua l l e a r ni ng ha s be e n s how n t o de ve l op ove r s hor t pe r i ods of t i m e t ypi c a l l y e xpe r i m e nt s t a ke s e ve r a l hour s f or a ny i ndi vi dua l s ubj e c t S e c o nd, i ns t r uc t i ons m a y not ha ve be e n s uf f i c i e nt l y e xpl i c i t S ubj e c t s s e e m t o ha ve ha d di f f i c ul t y m a i nt a i ni ng f i xa t i on i n t he e xpe r i m e nt T hi s r e m a i ns a m a j or pr obl e m f or t hi s t ype of t a s k, de s pi t e r e pe a t e d r e m i nde r s f or s ubj e c t s W hi l e t he num be r of m i s s e d f i xa t i ons di d not va r y a s a f unc t i on of bl oc k o r pr i m e t he num be r of e r r or s w a s s t i l l hi ghe r t ha n i de a l P r e s e nt i ng s t i m ul i pe r i phe r a l l y i s j us t one t e c hni que of pul l i ng pe r f or m a nc e a w a y f r om c e i l i ng F ut u r e r e s e a r c h m a y ne e d t o e m pl oy s a ndw i c h m a s ks di v i de a t t e nt i on i n a w a y t ha t doe s n t i nvol ve a t t e ndi ng t o m ul t i pl e s pa t i a l l oc a t i ons or s om e s i m i l a r m a ni pul a t i on\n38 O nc e pe r f or m a nc e w a s e qua l i z e d be t w e e n pr i m e c ondi t i ons by de l e t i ng da t a f r om s ubj e c t s w ho m i s s e d t oo m a ny f i xa t i ons one c a n s e e ge ne r a l l y l e s s noi s y l e a r ni ng f unc t i ons i n f i gu r e 11 W hi l e s t a t i s t i c a l t e s t s c a nnot be e m pl oye d be c a us e t he di f f e r e nt i a l r e m ova l of s ubj e c t s f r om c ondi t i ons r e nde r s a na l ys e s de pe nde nt i t i s c l e a r t ha t i f one r e m ove s s ubj e c t s w ho m i s s e d t o m a ny f i xa t i ons t h e l e a r ni ng t a s k doe s not m ove t ow a r d s upe r i or l e a r ni ng i n t he ne ga t i ve c ondi t i on. P i l ot e xpe r i m e nt 1 onl y us e d pos i t i ve a nd ne ga t i ve i m a ge s I n c ont r a s t i n t he s e c ond pi l ot a nd t he p r e s e nt e xpe r i m e nt t h r e e va l e nc e c ondi t i ons w e r e e m pl oye d. I t w a s a nt i c i pa t e d t ha t m or e va l e nc e l e ve l s i n t he p r i m i ng s t i m ul i w oul d a l l ow m o r e de t a i l e d c onc l us i ons r e ga r di ng t he c a us e of di f f e r e nc e s obs e r ve d i n t he va l e nc e c ondi t i ons U nf or t una t e l y, t he da t a i s e qui voc a l N o r e l i a bl e d i f f e r e nc e s w e r e obs e r ve d be t w e e n t he pr i m i ng c ondi t i ons i n t hi s f i na l e xpe r i m e nt D i f f e r e nc e s be t w e e n t he ne ga t i ve a nd pos i t i ve c ondi t i ons i n t he t w o pi l ot e xpe r i m e nt s w oul d s e e m t o i ndi c a t e t ha t t he di f f e r e nc e s be t w e e n c ondi t i ons i s due t o be ne f i t s a s s oc i a t e d w i t h vi e w i ng ne ga t i ve i m a ge s a s o ppos e d t o c os t s a s s oc i a t e d w i t h vi e w i ng pos i t i ve or ne ut r a l i m a ge s H ow e ve r s uc h a n e xpl a na t i on c a nnot be e xc l ude d. C e r t a i n m ode l s of a f f e c t s ugge s t t ha t pos i t i ve a f f e c t c a n be c ons i de r e d a s i gn t ha t a t t e nt i on s houl d be di r e c t e d e l s e w he r e ( C a r ve r 2003 ) I f t ha t w e r e t he c a s e pe r f o r m a nc e di f f e r e nc e s w oul d no t be s ol e l y t he r e s ul t of t he ne ga t i ve i m a ge s A ddi t i ona l r e s e a r c h ha s i ndi c a t e d t ha t pos i t i ve a f f e c t i s a s s oc i a t e d w i t h a br oa de ni ng of v i s ua l a t t e nt i on, a s m e a s ur e d by di m i ni s he d pe r f or m a nc e i n a f l a nke r t a s k ( R ow e e t a l 2006) I t ha s be e n s ugge s t e d f or s om e t i m e t ha t a r ous a l o r f e a r m i ght r e s ul t i n a na r r ow i ng of a t t e nt i ona l f oc u s ( B a dde l e y, 1972) T hi s c oul d\n39 c onc e i va bl y e xpl a i n t he c l e a r t r a de of f be t w e e n c e n t r a l c ha r a c t e r a nd of f s e t a c c ur a c y i n t he ne ga t i ve pr i m e c ondi t i ons M a ny of t he pr ob l e m s a s s oc i a t e d w i t h t he a f f e c t i ve m a ni pul a t i on i n t hi s e xpe r i m e nt a l de s i gn c a n be r e m e di e d by us i ng t e c h ni que s s i m i l a r t o t hos e e m pl oye d i n P L r e s e a r c h. I n m uc h t he s a m e w a y t ha t r e s e a r c he r s w ho w i s h t o l e a r n a bout t he r ol e of e xpe r i e nc e i n pe r c e pt i on ga i n gr e a t e r e xpe r i m e nt a l c ont r ol by c r e a t i ng w hol l y nove l s i t ua t i ons i n w hi c h e xpe r i e nc e c a n be m a ni pul a t e d e xpe r i m e nt a l l y, a f f e c t i ve m a ni pul a t i ons c a n be m or e f i ne l y c ont r ol l e d by c r e a t i ng w hol l y ne w va l e nc e d a s s oc i a t i on s i n a n a r t i f i c i a l s e t t i ng. S ub j e c t c a n be t r a i ne d t o a s s oc i a t e a gi ve n c ue w i t h e i t he r pos i t i ve or ne ga t i ve c ons e que nc e s T hi s m i ni m i z e s t he i nf l ue nc e of pe r s ona l i t y va r i a bl e s pr e e xpe r i m e nt a l e xpe r i e nc e o r ot he r i n di vi dua l di f f e r e nc e s va r i a bl e s w hi c h m i ght i nf l ue nc e r e a c t i ons t o a f f e c t i ve c ue s R a t he r t ha n pr e s e nt i ng s ubj e c t s w i t h i m a ge s t ha t va r y a l ong num e r ous di m e ns i ons s t i m ul i c a n be s e l e c t e d w hi c h m i ni m i z e va r i a t i on W he n l ooki ng f o r w ha t m a y be s m a l l di f f e r e nc e s b e t w e e n va l e n c e c ondi t i ons s e ns i t i vi t y c a n be i nc r e a s e d by di r e c t l y m a ni pul a t i ng t he e xpe c t a t i ons of pa r t i c i pa nt s r e ga r d i ng t he a f f e c t i ve c ue O ve r a l l t hi s e xpe r i m e nt e xe m pl i f i e s m a ny of t he c ha l l e nge s r e s e a r c he r s f a c e w he n a t t e m pt i ng t o i nt e gr a t e pa r a di gm s a s s oc i a t e d w i t h di f f e r e nt a r e a s of i nqui r y. W hi l e a f f e c t i ve m a ni pul a t i ons m a y r e m a i n a vi a bl e t ool f or r e s e a r c he r s t o be t t e r unde r s t a nd t he r e l a t i ons hi p be t w e e n a t t e nt i on a nd P L gr e a t e r t hou ght c a r e e xpe r i m e nt a l c ont r ol w i l l be r e qui s i t e i f r e l i a bl e i nf e r e nc e s a r e t o be d r a w n.\n40 R e f e r e nc e s A hi s s a r M & H oc hs t e i n, S ( 2004) T he r e ve r s e h i e r a r c hy t he or y of vi s ua l pe r c e pt ua l l e a r ni ng. T r e nds i n C ogni t i v e Sc i e nc e s 8 ( 10) 457 464. A hi s s a r M & H oc hs t e i n, S ( 2002) T he r ol e of a t t e nt i on i n l e a r ni ng s i m pl e vi s ua l t a s ks I n M F a hl e & T P oggi o ( E ds ) P e r c e pt ual l e ar ni ng. 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P s y c hol ogi c al Sc i e nc e 17, 287 291\n45 F i gur e 1. V e r ni e r s t i m ul us us e d i n pi l ot e xpe r i m e n t 1. 5\n46 F i gur e 2. E xpe r i m e nt 1 S e que nc e C a l i br a t i on S t a ge F i xat i on 150m s T ar ge t 100m s I n i t i al P r o m p t unt i l r e s pons e S e c on d P r om p t unt i l r e s pons e\n47 F i gur e 3. E xpe r i m e nt 1 S e que nc e V a l e nc e d pr i m e S t a ge F i xat i on 150m s P r i m e 500 m s T ar ge t 100m s I n i t i al P r o m p t unt i l r e s pons e S e c on d P r om p t unt i l r e s pons e\n48 F i gur e 4. G r a ph s how i ng m i s s e d f i xa t i ons i n P i l ot E xpe r i m e nt 1\n49 F i gur e 5. R a t e o f L e a r ni ng f or s ubj e c t s i n P i l ot E x pe r i m e nt 1\n50 F i gur e 6. M i s s e d F i xa t i ons i n P i l ot E xpe r i m e nt 2.\n51 F i gur e 7. N or m a l i z e d l e a r ni ng i n P i l ot E xpe r i m e nt 2\n52 F i gur e 8. G r a ph s how i ng m i s s e d f i xa t i ons i n E xpe r i m e nt 3 P ri m e s t a rt s 5 m i n u t e b re a k P ri m e s t o p s\n53 F i gur e 9. P e r f o r m a nc e f or pa r t i c i pa nt s i n t he E xpe r i m e nt P ri m e s t a rt s 5 m i n u t e b re a k P ri m e s t o p s\n54 F i gur e 10. M i s s e d F i xa t i ons i n E xpe r i m e nt onc e s ubj e c t s e xc l ude d t o e qua l i z e pe r f or m a nc e P ri m e s t a rt s 5 m i n u t e b re a k P ri m e s t o p s\n55 F i gur e 11. P e r f o r m a nc e i n t he of f s e t t a s k f or t he E xpe r i m e nt onc e t he g r oups w e r e t r i m m e d t o e qua l i z e pe r f o r m a nc e P ri m e s t a rt s 5 m i n u t e b re a k P ri m e s t o p s