explain any one behavior. Some can be quite extensive, including many con-
cepts and assumptions, whereas others explain the phenomenon in relativelysimple terms. Which theory is better? Although it sometimes seems that scien-
tists enjoy wrapping their work in fancy terms and esoteric concepts, the
truth is that if two theories can account for an effect equally well, the simpler
explanation is preferred.
Second, a good theory is useful. More specifically, unless a theory can
generate testable hypotheses, it will be of little or no use to scientists. Ideasthat cannot be tested are not necessarily incorrect. It ’s just that they do not
lend themselves to scientific investigation. For example, throughout historypeople have explained psychological disorders in terms of invisible demonstaking over a person’ s body. This may or may not be a correct statement
about the causes of disorders. But unless this explanation is somehow test-able, the theory cannot be examined through scientific methods and thereforeholds little value for scientists.
However, theories themselves are never tested. Instead, investigators de-
rive from the theory hypotheses that can then be tested in research.
Ahypothesis is a formal prediction about the relationship between two or
more variables that is logically derived from the theory. For example,
many psychologists are interested in individual differences in loneliness
(Chapter 12). That is, they want to know why some people frequently suf-
fer from feelings of loneliness, whereas others rarely feel lonely. One theory
proposes that lonely people lack the social skills necessary to develop and
maintain satisfying relationships. Because this is a useful theory, many
predictions can be logically derived from it, as shown in Figure 2.1. For
example, if the theory correctly describes a cause of loneliness, we might
expect consistently lonely people to make fewer attempts to initiate conver-
sations than those who are not lonely. Another prediction might be
that these lonely people have a poor idea of how they are being perceivedby others. Yet another prediction might maintain that lonely people
make more socially inappropriate statements than nonlonely people during
conversations.
Each of these predictions can be tested. For example, we might test the
last prediction by recording conversations lonely and nonlonely peoplehave with new acquaintances. Judges could evaluate the conversations interms of number of appropriate responses, number of appropriate questions,
and so on. If people who identify themselves as lonely make fewer appropri-
ate responses during the conversation, the prediction is confirmed. We thensay we have support for the theory. But notice that the theory itself is not
tested directly. In fact, theories are never proved or disproved. Rather, a the-
ory is more or less supported by the research and therefore is more or lessuseful to scientists trying to unders tand the phenomenon. The more often
research confirms a prediction derived from a theory, the more faith psy-chologists have that the theory is accurately describing the nature of things.However, if empirical investigations consistently fail to confirm predictions,
we are much less likely to accept the theory. In these cases, scientistsThe Hypothesis-Testing Approach 21