data. Finally, because personality psychologists often rely on personality assess-
ment, we quickly review some of the concepts associated with measuring individ-ual differences in personality.
THE HYPOTHESIS-TESTING APPROACH
Each of us on occasion speculates about the nature of personality. You may
have wondered why you seem to be more self-conscious than others, why a
family member is depressed so often, or why you have so much trouble mak-ing friends. In the latter case, you may have watched the way a popular stu-
dent interacts with the people she meets and compared her behavior with
the way you act around strangers. You may have even tried to change yourbehavior to be more like hers and then watched to see if this affected how
people reacted to you.
In essence, the difference between this process and that used by personal-
ity psychologists lies only in the degree of sophistication. Like all of us,
personality researchers speculate about the nature of personality. From
observations, knowledge about previous theory and research, and carefulspeculation, these researchers generate hypotheses about why certain people
behave the way they do. Then, using experimental methods, investigators
collect data to see if their explanations about human behavior are correct.
Like pieces in a large jigsaw puzzle, each study makes another contribution to
our understanding of personality. However, by the time you get to the end of
this book, it should be clear that this is one puzzle that will never be finished.
Theories and Hypotheses
Most personality research begins with a theory —a general statement about the
relationship between constructs or events. Theories differ in the range of events
or phenomena they explain. Some, such as the major personality theories
discussed in this book, are very broad. Psychologists have used Freud ’sp s y -
choanalytic theory to explain topics as diverse as what causes psychological
disorders, why people turn to religion, and why certain jokes are funny.
However, personality researchers typically work with theories considerably nar-rower in application. For example, they might speculate about the reasons
some people are more motivated to achieve than others or about the relation-
ship between a parent ’sb e h a v i o ra n dac h i l d ’s level of self-esteem. It might be
useful to think of the larger theories, such as Freud ’s, as collections of more
specific theories that share certain assumptions about the nature of humanpersonality.
A good theory possesses at least two characteristics. First, a good theory
isparsimonious. Scientists generally operate under the “law of parsimony”—
that is, the simplest theory that can explain the phenomenon is the best. As
you will see throughout this book, several theories can be generated to20 CHAPTER 2 Personality Research Methods