are generalized dispositions, finding expression in a variety of specific
acts. Habits are thoughtless repetitions of earlier behavior; traits oftenlead people to develop entirely new behaviors, sometimes after muchthought and planning. Driving fast may simply be a habit, perhapslearned from observing the way friends or parents drive. But if the fastdriver also likes loud music and roller coasters, and perhaps experi -
ments a bit with drugs, we begin to see a general pattern we can identify
as excitement seeking (Zuckerman, 1979). An excitement seeker mayspend weeks planning for a trip to Las Vegas, say , or she may decide togo on the spur of the moment. But in either case going to Las Vegas isnot likely to be simple habit. In many respects traits resemble motivesrather than habits, and it is often unclear whether a disposition such asexcitement seeking should be called a trait or a motive. T rait appears to
be the broader term, indicating motivational, stylistic, and other aspectsof human consistency .
Theconsistent patterns that indicate traits must be seen over time as
well as across situations. This means that traits are to be distinguishedfrom passing moods, transient states of mind, or the effects of tempo-rary stress and strain. If an individual is anxious and hostile today butcalm and good natured tomorrow , we attribute these emotions to thesituation—perhaps pressures at work or a quarrel with a spouse. Onlywhen emotion, attitude, or style persists despite changes in circum-stances do we infer the operation of a trait. Measures of personalitytraits are expected to show high retest reliability when administered onseparate occasions days or weeks apart, because traits are characteristicnot of situations, seasons, or times of day but of the individual at a par -
ticular point in his or her life.
Short-term consistency does not preclude long-term change. In
fact, there could be neither stability nor change without a consistentpattern to begin with. From a trait perspective, personality changemeans that one consistent pattern is replaced by another. We review theevidence for such changes in Chapters 4–7.
Note that our definition of traits says nothing about their origins.
Psychodynamic theories emphasize interactions of children with theirparents; social psychological theories may point to peer pressures.There is increasing evidence for the importance of genetic influences onmany traits (Plomin & Daniels, 1987; Jang, Livesley , & Vernon, 1996).Whatever their origin, by adulthood individuals can be characterized interms of a variety of traits, and research on personality and aging can28 PERSONALITY IN ADULTHOOD