characterization by a single trait. But humans have only stereotypes
to go on in the absence of more information. Therefore, one way to
combat stereotypes and stereotyping is to disseminate more infor-
mation about group variability and about other traits.
PEC theory goes even farther than the psychology of individual
differences. PEC theory postulates that there are E differences as
well as P differences. When P and E interact, we have a multiplica-
tive situation. P ×E is much more than P +E, much more than P
differences and E differences combined.
Cultural Validity
The theoretical structure of PEC theory and its constructs can apply
to any culture. People in any culture will have needs and skills, abil-
ities and values, satisfaction and satisfactoriness, maintenance and
adjustment. But there will be cultural differences. Even when it is
valid and possible to use the same instruments with different cultural
groups, one should expect differences in their means and, to a much
lesser extent, in their variabilities. Intercorrelation among variables
should be the least different among cultural groups, as studies in indi-
vidual differences have shown.
However, most frequently it is the instruments that do not apply
in theory transfer. It is a very difficult undertaking to demonstrate
measurement equivalence across cultural groups. Language differ-
ences will be a major stumbling block; translation of an instrument
into another language has always been fraught with problems. Even
when the same language is spoken, there may be cultural differences
in meaning for certain words and phrases. Thus the problem of cul-
tural validity may lie not so much in the theory as in the instruments
used to operationalize the theory. This is a sort of chicken-and-egg
problem because a theory cannot be validated for another culture
without the use of instruments. (PEC theory has not been validated
for any culture other than the contemporary, English-speaking,
Anglo-American culture.)
458 CAREER CHOICE AND DEVELOPMENT