fei75766_ch15_463-494.indd 470  02/24/20 10:48 AM
Part V    Biological/Evolutionary Theories470
from theenvironment. Neither canfunction without theother, although thehistory 
ofpsychology islargely ahistory ofnature versus nurture. Ontheoneside,there is
what Busscalled thefundamental situational error, orthetendency toassume thatthe
environment alone canproduce behavior voidofastable internal mechanism. “With -
outinternal mechanisms there canbenobehavior” (D.Buss, 1991, p.461). Onthe
other side,there iswhat social psychologists havecalled thefundamental attribution 
error todescribe ourtendency toignore situational andenvironmental forces when 
explaining thebehavior ofother people andinstead focus oninternal dispositions. 
Indeed, eachofthese views alone isincomplete because there isnosuchthing as
purely internal orpurely external explanations ofbehavior. Thetwomust beinvolved 
andinteract inanybehavior.
Evolved mechanisms aregood examples oftheinteraction ofnature andnur-
turebecause theyonlyexistinresponse toandwithinput from theenvironment. 
There isnosplitbetween biological andenvironmental. Environment doesnotaffect 
behavior without amechanism torespond. Evolution ingeneral isinherently aninter-
action between biology andenvironment (nature andnurture). Allbiological struc -
tures andbyextension allpsychological systems havecome about onlyinthecontext 
ofaparticular environment andwhat washappening inthatenvironment. During 
early stages ofevolution, some individuals hadqualities thatworked inthatenviron -
ment atthattimeandhence weremore likely tosurvive andreproduce. Oneofthe
fundamental assumptions ofevolutionary theory ofpersonality isthatthese adaptive 
qualities include consistent andunique dispositions tobehave inparticular ways in
particular contexts, inother words, personality traits.
Adaptive Problems and Their Solutions (Mechanisms)
Eversince Darwin, ithasbeenclearthatalllifeforms areconfronted withtwofun-
damental problems ofadaptation, namely survival (food, danger, predation, etc.)and
reproduction. Inorder tosurvive anyliving thing hastodealwithwhathecalled the
“hostile forces ofnature,” which include disease, parasites, foodshortages, harsh cli-
mate, predators, andother natural hazards (D.Buss, 1991). Individuals whosolve these 
problems most efficiently andeffectively aremost likely tosurvive, andsurvival isa
precondition forreproduction.
Theprocess ofevolution bynatural selection hasproduced solutions to
these twobasic problems oflifeandtheyarecalled mechanisms. More specifically, 
mechanisms
• operate according toprinciples indifferent adaptive domains
• number inthedozens orhundreds (maybe eventhousands)
• are complex solutions tospecific adaptive problems (survival, 
reproduction)
Each mechanism works specifically ontheproblem itsolves andnotother ones. 
Forexample, sweat glands solve theproblem ofregulating body temperature but
donothing fordisease orwounds. Psychological mechanisms operate byconverting 
input intoparticular actions ordecision rules thathelpsolve these adaptive prob -
lems(D.Buss, 1991).Final PDF to printer