fei75766_ch15_463-494.indd 465  02/24/20 10:48 AM
Chapter 15    Buss: Evolutionary Theory of Personality465
strategies arenotconscious withaplanorforesight inmind, butrather areblind (non -
conscious). Traits get“selected” simply because theyleadtogreater survivability and
hence more offspring withthattraitsurvive toreproductive age.These individuals, 
inturn, havemore offspring. Darwin’s genius wasbeing thefirst(along withAlfred 
Wallace) torecognize thiswastheprocess thatdrove evolution ofalllifeforms.
Darwin realized there were certain traits thatcontradicted natural selection 
because theydirectly made survival less,notmore, likely. Thebig,bulky, colorful 
feathers ofthepeacock were aprime example. Why dosuchcharacteristics existif
theymake survival more difficult? Hisanswer wassexual selection rather thannatu-
ralselection (Darwin, 1859; Miller, 2000). Sexual selection operates when members 
oftheopposite sexfindcertain traits more appealing andattractive thanothers and
thereby produce offspring withthose traits. Thekeyisthatthese qualities haveto
bemarkers offitness thatcan’t beeasily faked. Forinstance, intheexample ofthe
peacock, onlymales withthehealthiest andbrightest plumage aremost attractive 
topeahens. Butplumage cannot befaked—that is,notjustanymale canpretend 
tohavethebrightest plumage. Infact,thebrightest plumage isatruemarker offit-
ness, thatis,these really arethestrongest andhealthiest males inthecluster/pride 
(Zahavi &Zahavi, 1997). Infact,these traits arehandicaps thatonlythetrulystrong 
andhealthy canpulloff.They signal topeahens, “Hey, select me;Iamthestron -
gestandhealthiest.” Bymating withthese peacocks, peahens areunconsciously pro-
ducing thestrongest andhealthiest offspring. Inhumans, strength, physical beauty, 
dominance, intelligence, andstatus arequalities many findattractive andarethere -
foresexually selected for.Forexample, arecent study ofover400individuals, many 
ofwhom were creative artists andpoets, revealed apositive correlation between 
creativity andsexual success. Thatis,more creative people were alsomore sexually 
active (Nettle &Clegg, 2006). Theresearchers argue thattheirfindings support the
theory, firstproposed byDarwin andmore recently byGeoffrey Miller (2000), that
human creative ability isasexually selected traitbecause itisaquality thatincreases 
one’s attractiveness tomembers oftheopposite sex.
Theevolutionary process (natural andsexual selection andchance) results in
three distinct outcomes: adaptations, by-products, andnoise (D.Buss, 1999; Tooby &
Cosmides, 1992). Adaptations areevolved strategies thatsolve important survival 
and/or reproductive problems. Adaptations areoften theproducts ofnatural orsex-
ualselection andmust haveagenetic orinherited basis tothem. Sweat glands, for
example, areadaptations because theysolve theproblem ofthermal regulation. Taste 
preferences andsexual attraction arealsoadaptations. Welikesugary andfattyfoods 
because theyaregood sources ofenergy andinearlier evolutionary times wererela-
tively scarce. Human intelligence andcreativity areadaptations because theyfacili -
tateadaptive solutions toproblems ofsurvival (Feist, 2006; Miller, 2000).
By-products aretraits thathappen asaresult ofadaptations butarenotpartof
thefunctional design (D.Buss, 1999; Tooby &Cosmides, 1992). By-products “come 
along fortheride” ofnatural orsexual selection. Scientific ability ordriving skillis
eachaby-product ofadaptations. Weclearly didnotevolve todoscience ordrive 
cars,butoneby-product oftheevolution ofhuman intelligence isthecapacity to
think scientifically (Feist, 2006). Similarly, driving acarisnotanevolved strategy, 
buthaving quick reflexes, hand-eye coordination, andmotor (muscle) control allows 
useasily totransfer evolved skills tonew,modern applications, suchasdriving.Final PDF to printer