fei75766_ch13_408-434.indd 425  02/06/20 01:05 PM
Chapter 13    McCrae and Costa’s Five-Factor Trait Theory425
Consistency and Change of Personality over the Lifetime
Recall ourdefinition ofpersonality astheunique andenduring manner inwhich a
person thinks, feels, andbehaves. Although itshows considerable stability overour
lifetime, italsochanges anddevelops between ourinfant andadult years. Alldefini -
tions, theories, andmeasures ofpersonality confront thequestion ofconsistency and
change ofpersonality anditisparticularly prominent inthetraittheory perspective of
theBigFive. McCrae andCosta haveemphasized stability overchange andyetthere 
isevidence forboth. 
Personality Consistency
Inmany ways, itismore difficult tochange ourpersonalities thanwethink. Much 
ofwhoweareremains rather stable andconsistent overourlifetimes. When wetalk
about personality consistency, however, wemean relative consistency. Nooneiscon-
sistent allofthetimeorinallsituations. Consistency isamatter ofdegree.
Longitudinal studies, those thatexamine thesame people overaperiod oftime, 
reveal highlevels ofstability ofpersonality traits. Early intheircollaboration, Costa 
andMcCrae (1976) conducted alongitudinal study ofpersonality, expecting tofind
thatpersonality traits change overtime. Totheirsurprise, theyfound ahighdegree of
stability overa10-year period. Another setoflongitudinal studies revealed verysmall 
changes inneuroticism, extraversion, andopenness overaperiod of6–9years (Costa 
etal.,2000; McCrae &Costa, 2003).
Research from behavior genetics hasdemonstrated thatpersonality stability 
between adolescence andadulthood islargely duetogenetic factors (Blonigen etal.,
2006; Gillespie etal.,2003; Krueger &Johnson, 2008; Takahashi etal.,2007). More 
specifically, genetics contributes tothepersonality consistency weseefrom adoles -
cence toadulthood, whereas environmental factors contribute tobothstability and
change inpersonality traits (Takahashi etal.,2007).
Most parents orobservers ofinfants andtoddlers arequick toproject subtle 
signs oftheirchildren’s interest ortalent intothefuture, butdoourpersonalities and
traits atage3portend future outcomes suchasemployment, mental illness, criminal 
behavior, andquality ofinterpersonal relationships? Block, Block, andKeyes (1988) 
conducted some ofthefirstlong-term studies ofhuman temperament andpersonality. 
They conducted interviews, behavioral observations, andpersonality questionnaires 
andfound thatchildren whowereimpulsive, aggressive, andtended tocryatage3
weremost likely tousedrugs during adolescence. Inseparate butrelated research, 
temperament ratings weremade onnearly 1,000 three-year olds,whowerethenfol-
lowed upthrough theirteens, 20s,and30s.Being under controlled andimpulsive at
age3predicted adult alcoholism, drugabuse, andgambling problems (Caspi, 2000; 
Slutske, Moffitt, Poulton, &Caspi, 2012).
Personality Change
Weallliketothink wecanchange—that wehavethepower tochange ourdestructive 
habits andbecome abetter person. Canwe?Willful andintentional change ofper-
sonality appears tobedifficult. Most change inpersonality comes about bychange in
life-circumstance orbrain functioning. Final PDF to printer