fei75766_ch15_463-494.indd 478  02/24/20 10:48 AM
Part V    Biological/Evolutionary Theories478
Furthermore, Nettle (2006) hypothesized there havebeenfitness costs andben-
efitsofeachoftheBigFivedimensions ofpersonality during ancestral periods ofevolu -
tion(seeTable 15.2). Forexample, benefits ofbeing extraverted include being more 
successful atmating, making social allies, andexploring one’s environment, whereas 
evolutionary costs ofextraversion include taking more physical risksandhaving poten -
tially alessstable family (i.e.,more affairs). Abenefit ofbeing open toexperience is
heightened creativity, anditscosts arehaving more unusual beliefs andpossibly even
developing psychosis. High levels ofconscientiousness havethebenefit ofcausing one
topaycloser attention tothedetails ofphysical self-care andhence canleadtoalonger 
andhealthier life,butalsoheighten theriskofleading torigidandcompulsive behavior.
Common Misunderstandings in  
Evolutionary Theory
When evolutionary theory firstbecame popular inthe1980s itcaused quite abitof
controversy. There wasalotofresistance bothfrom inside andoutside university set-
tings against applying evolutionary ideas tohuman thought andbehavior. Although 
much ofthisresistance hasdieddown overthelast20–30 years, there aresome mis-
understandings thatstilloccur (D.Buss, 1999).
Evolution Implies Genetic Determinism (Behavior as Set in Stone 
and Void of Influence From the Environment)
Evolution isallabout thebody changing duetochanges intheenvironment. Inthis
sense, itisinherently a“nature andnurture” interaction perspective. Evolution occurs 
from theinteraction between adaptations andinput from theenvironment thattriggers TABLE 15.2
Costs and Benefits of Big Five Dimensions of Personality (Nettle, 2006)
Domain  Benefits  Costs
Extraversion  Mating success; social allies;  Physical risks; family stability 
 exploration ofenvironment 
Neuroticism  Vigilance todangers; striving and Stress anddepression, with
 competitiveness  interpersonal andhealth 
  consequences
Openness  Creativity, witheffect on Unusual beliefs; psychosis 
 attractiveness 
Conscientiousness  Attention tolong-term fitness  Missing ofimmediate fitness 
 benefits; life-expectancy and gains; obsessionality; rigidity 
 desirable social qualities 
Agreeableness  Attention tomental states of Subject tosocial cheating; 
 others; harmonious interpersonal  failure tomaximize selfish 
 relationships; valued coalitional  advantage 
 partner
From Nettle (2006), copyright American Psychological Association; reprinted with permission.Final PDF to printer