fei75766_ch13_408-434.indd 430  02/06/20 01:05 PM
Part IV    Dispositional Theories430
Key Terms and Concepts
•Trait andfactor theories ofpersonality arebased onfactor analysis, a
procedure thatassumes thathuman traits canbemeasured bycorrelational 
studies.
•Extraverts arecharacterized bysociability andimpulsiveness; introverts, by
passivity andthoughtfulness.
•High scores ontheneuroticism scale mayindicate anxiety, hysteria, 
obsessive-compulsive disorders, orcriminality; lowscores tendtopredict 
emotional stability.Thefinalcriterion ofauseful theory isparsimony. Ideally, traitandfactor theo-
riesshould receive anexcellent rating onthisstandard, because factor analysis is
predicated ontheideaofthefewest explanatory factors possible. Inother words, the
verypurpose offactor analysis istoreduce alarge number ofvariables toasfewas
possible. Thisapproach istheessence ofparsimony. 
 Concept of Humanity
How do trait and factor theorists view humanity? The Five-Factor theorists 
were not concerned with traditional themes such as determinism versus free 
choice, optimism versus pessimism,  and teleological versus causal  influ -
ences. In fact, their theories do not lend themselves to speculation of these 
topics. What, then, can we say concerning their view of humanity?
First, we know that factor analysts see humans as being different from 
other animals. Only humans have the ability to report data about themselves. 
From this fact, we can infer that McCrae and Costa believed that humans pos -
sess not only consciousness  but self-consciousness as well. People are also 
able to evaluate their performance and to render reasonably reliable reports 
concerning their attitudes, temperament, needs, interests, and behaviors.
Second, McCrae and Costa placed emphasis on genetic factors  of per -
sonality. They believe that traits and factors are both inherited and have 
strong genetic and biological components and hence are universal. But they 
also believed that environment plays a crucial role in shaping a person’s 
dispositions. Therefore, we rate the Five-Factor model as medium on social 
influences.
On the dimension of individual differences versus similarities,  trait and 
factor theories lean toward individual differences. Factor analysis rests on 
the premise of differences among individuals and thus variability in their 
scores. Thus, trait theories are more concerned with individual differences 
than with similarities among people.Final PDF to printer