fei75766_ch15_463-494.indd 485  02/24/20 10:48 AM
Chapter 15    Buss: Evolutionary Theory of Personality485
Animal Personality
Most ofyouwhohaveeverowned petcatsordogswould readily agree thatyour
petshavetheirownunique personalities. Oneofyourauthors (GJF), forexample, 
currently hastwosibling cats,amale (Scooter) andafemale (Belle). These twocats
could hardly bemore different interms oftheirbehavior andpersonality. Scooter is
absolutely curious andsociable. Heexplored every inchofhisnewhome onthefirst
dayandforces himself intoevery oneofouractivities—eating, watching TV,work -
ingatthecomputer, andsleeping. Notonce hashebeen afraid ofanysituation. He
approaches everything withgleeandwonder. Belle, however, hasbeen anxious and
shyfrom thebeginning. Ittookherabout 3daystocome outofhiding andbecome 
comfortable withhernewhome. Sheplays, butnotsomuch withstrangers. Sheloves 
playing withherbrother, however, andtheyregularly tease andchase eachother. 
Now shehangs outwiththefamily andenjoys agood massage, butsheisstillskittish 
tosudden approaches.
Topetowners thequestion ofanimal personality seems tohaveanobvious 
answer: Ofcourse, animals havedistinct personalities. Buttopsychologists theques-
tionmight seem tobestretching thedefinition ofpersonality toofar.Butevenifwe
canseeevidence ofpersonality inanimals suchasdogsandcats,canweseeitin
other animals? What about birds? reptiles? fish?worms?
Until the1990s, most psychologists would haveargued thatthetermperson -
alitymade sense onlyasapplied tohumans, butsince thennumerous studies have
supported thenotion thatnonhuman animals notonlyhavedistinct personalities but
theyhavepersonalities ondimensions similar totheBigFiveinhumans (Barnard 
etal.,2016; Dingemanse, Both, Drent, VanOers, &VanNoordwijk, 2002; Gosling, 
1998; Gosling, Kwan, &John, 2003; Rayment, Peters, Marston, &DeGroef, 2016;  
Suwała, Górecka-Bruzda, Walczak, Ensminger, &Jezierski, 2016; Weinstein, Capi -
tanio, &Gosling, 2008). Forexample, Gosling andOliver John (1999) conducted a
meta-analysis (quantitative review) of19studies across 12nonhuman species. They 
found evidence foratleast14nonhuman species withpersonality traits thatcanbe
categorized along thesame dimensions ashuman personality. Thesummary ofthese 
findings ispresented inTable 15.4. Keep inmind thatthelabels from theBigFive
aregeneral labels, andthespecific onesusedinthese studies varysomewhat. For
instance, neuroticism issometimes called emotional stability, excitability, fearfulness, 
emotional reactivity, fear–avoidance, oremotionality. Agreeableness issometimes 
labeled aggression, hostility, understanding, opportunistic, sociability, affection, or
fighting–timidity. Inaddition, dominance–submission isatraitthatisoften seenand
measured innonhuman animals, butitdoesnotfitintoanyoftheBigFivecategories. 
These ratings ofanimal personality weremade byoneoftwobehavioral observation 
techniques: either byanimal trainers whohadextensive knowledge oftheindividual 
animals orbytrained observers withnohistory withtheanimals butwhoweretrained 
untiltheycould reliably evaluate thedimensions inquestion.
Itmaynotsurprise youthatprimates andother mammals tendtoshare thelarg-
estnumber ofpersonality traits withhumans (Weinstein etal.,2008). Forinstance, 
chimpanzees, ourclosest relative, share withhumans adistinct “conscientiousness” 
dimension. Such afinding suggests thatconscientiousness—which involves impulse 
control andtherefore requires highly developed brain regions capable ofcontrolling Final PDF to printer