basis of the weak relationship between trait measures and behavior. But how
high does a correlation have to be before it is considered important? Oneteam of researchers answered this question by looking at several social-
psychological (situation-focused) investigations often cited for their “impor-
tant”findings (Funder & Ozer, 1983). The researchers converted the data
from these studies into correlation coefficients and found they ranged from
.36 to .42. In short, the “important ”effects of situational variables are, statis-
tically speaking, no more important than the effects deemed weak by critics
of personality traits.
Yet another way to examine the importance of such correlations is to
compare the amount of variance accounted for in personality research withthe typical results from other fields. One psychologist looked at some highly
acclaimed research in the field of medicine (Rosenthal, 1990). One large med-
ical study he examined made headlines when researchers found that aspirinsignificantly reduced the risk of heart attacks. In fact, the investigators ended
the experiment earlier than planned because the results were so clear. To con-
tinue to give one group of patients placebo pills instead of aspirin would havebeen unethical. Obviously, the researchers considered this an important find-
ing. Yet when we examine the data, we find that the medical researchers
were dealing with a correlation of around .03, which accounted for less than
1% of the variance! Another team of investigators looked at the relation be-
tween personality measures and important life events like mortality, divorce,
and success at work (Roberts, Kuncel, Shiner, Caspi, & Goldberg, 2007).
Not only were personality traits significantly related to these events, but they
accounted for as much or more variance than socioeconomic status or cogni-
tive ability measures (e.g., IQ), two concepts typically considered to be impor-
tant determinants of behavior.
The point is that importance is a subjective judgment. When dealing with
medical treatments, reliably saving a relatively small number of lives is impor-tant. When trying to predict behavior from personality test scores, we must
remember that most of the behaviors we are interested in are determined by
a large number of causes. No one will ever discover a single cause for whypeople suffer from schizophrenia or why consumers buy one product over an-
other. Rather, the goal of most studies is to account for some of the variance
in these behaviors. When we think about all the complex influences on our
behavior, we probably should be impressed that personality psychologists
can explain even 10%.
APPLICATION: THE BIG FIVE IN THE WORKPLACE
Imagine you own your own business and have to make a quick hiring decision.
You have five applications on your desk, all nearly identical. You notice that
each applicant ’s file includes some personality test scores. Specifically, you
have scores for each job candidate on each of the Big Five personality dimen-
sions. A quick glance through the applications tells you that each applicant
has one score that distinguishes him or her from the rest of the pack. One ap-
plicant is high in Extraversion, another scored very low on Neuroticism, and170 CHAPTER 7 The Trait Approach