fei75766_ch13_408-434.indd 424  02/06/20 01:05 PM
Part IV    Dispositional Theories424
number ofpersonality dimensions isfiveandonlyfive.Thisnumber ismore than
thethree hypothesized byEysenck andconsiderably fewer than35found byCat-
tell.With thestructure postulate, McCrae andCosta andother five-factor theorists 
converge onfiveastheanswer tothelong-standing debate among factor theorists.
Postulates for Characteristic Adaptations 
Thepostulate concerning characteristic adaptations states that,overtime, people 
adapt totheirenvironment “byacquiring patterns ofthoughts, feelings, andbehaviors 
thatareconsistent withtheirpersonality traits andearlier adaptations” (McCrae &
Costa, 2003, p.190). Inother words, traits affect thewayweadapt tothechanges 
inourenvironment. Moreover, ourbasic tendencies result inourseeking andselect -
ingparticular environments thatmatch ourdispositions. Forinstance, anextraverted 
person mayjoinadance club, whereas anassertive person maybecome alawyer or
business executive.
Thesecond characteristic adaptation postulate—maladjustment—suggests that
ourresponses arenotalways consistent withpersonal goals orcultural values. For
example, when introversion iscarried toanextreme, itmayresult inpathological 
social shyness, which prevents people from going outofthehouse orholding down a
job.Also, aggression carried toanextreme mayleadtobelligerence andantagonism, 
which thenresult inbeing frequently firedfrom jobs.These habits, attitudes, and
competencies thatmake upcharacteristic adaptations sometimes become sorigidor
compulsive thattheybecome maladaptive. 
Thethird characteristic adaptation postulate states thatbasic traits may
“change overtimeinresponse tobiological maturation, changes intheenvironment, 
ordeliberate interventions” (McCrae &Costa, 2003, p.190). ThisisMcCrae and
Costa’s plasticity postulate, onethatrecognizes thatalthough basic tendencies may
berather stable overthelifetime, characteristic adaptations arenot.Forexample, 
interventions suchaspsychotherapy andbehavior modification mayhaveadifficult 
timechanging aperson’s fundamental traits, buttheymaybepotent enough toaltera
person’s characteristic responses. 
Related Research
Thetraitapproach taken byRobert McCrae andPaulCosta isverypopular inthe
fieldofpersonality. Costa andMcCrae havedeveloped awidely usedpersonality 
inventory, namely theNEO-PI (Costa &McCrae, 1985, 1992). 
Traits havebeen linked tovitaloutcomes suchasphysical health (Martin, 
Friedman, &Schwartz, 2007), well-being (Costa &McCrae, 1980), andacademic 
success (Noftle &Robins, 2007; Zyphur, Islam, &Landis, 2007); buttraits havealso
been linked tomore common, everyday outcomes suchasmood (McNiel &Fleeson, 
2006). Infact,theBigFivetraits havebeen shown topredict mortality, divorce ,and
career success atleastaswellasintelligence andsocio-economic standing (income 
andeducation) (Roberts, Kuncel, Shiner, Caspi, &Goldberg, 2007). Twoquestions 
thathavereceived alotofempirical attention havebeen: (a)doespersonality change 
orstaythesame overourlifetime? and(b)doesourpersonality reflect howweuse
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