506 Chapter 13field with people facing actual stressful life
events; thus the research has good external
validity. However, recall that the cost of field
research is often a loss of internal validity. Is
rumination an actual cause of depression?
The reciprocal nature of the relation between
rumination and depression shows that de-
pression also causes rumination. One way to
address the causal issue is to conduct an ex-
periment in a controlled laboratory setting.
Just such an experiment was conducted
and showed that inducing depressed people
to ruminate increases their depression and
inducing depressed people to distract reduces
their depression (Lyubomirsky & Nolen-
Hoeksema, 1993). Rumination and distraction
were manipulated in the laboratory by having
depressed and nondepressed college students
either think about their feelings and why they
are the kind of person they are (rumination
condition) or think about external events (dis-
traction condition). Among depressed stu-
dents, rumination increased depressed mood
and distraction reduced depressed mood.
However, rumination and distraction had
no effect on nondepressed students’ moods.
There was also evidence that the rumination
manipulation interfered with the potential for
instrumental behavior among depressed stu-
dents. Depressed students who were induced
to ruminate about themselves reported they
were less likely to engage in a list of pleasant
activities (e.g., go to dinner with friends, play
favorite sport) than the other students.
Why are women more likely than men
to ruminate in response to stressful events?
One possibility is that people encourage
women to ruminate. A behavioral observa-
tion study of adolescents and their mothers
showed that mothers were more likely to en-
courage their 11-year-old girls than boys to
engage in emotional expression when discuss-
ing a stressor (Cox, Mezulis, & Hyde, 2010).What is the evidence that rumination
leads to more depression, and distraction
leads to less depression? A meta-analytic re-
view of the literature showed that rumina-
tion is associated with current depression
and predicts future depression (Rood et al.,
2009). When baseline levels of depression are
taken into consideration to see if rumination
predicts changes in depression over time,
the effect is smaller but remains significant.
Rumination is more strongly linked to the
onset of depression than the duration of de-
pression (Nolen-Hoeksema et al., 2008). As
for distraction, there is a small effect for dis-
traction to be associated with lower levels of
current depression but distraction does not
predict changes in depression over time.
One concern that has been raised about
the relation of rumination to depression is that
some of the rumination items are confounded
with depression. If you review the items in
Table 13.4, you will see that the first four items
involve ruminating about depression. That is,
you are thinking about how depressed you feel.
This makes the theory somewhat circular be-
cause in order to think about negative feelings,
you have to have those negative feelings. When
the items that overlapped with depression were
removed from the scale, the remaining items
formed two sets of traits: (1) reflective pon-
dering (as indicated by items 5, 6, and 7) and
(2) brooding (as indicated by items 8, 9, and
10; Treynor, Gonzales, & Nolen-Hoeksema,
2003). The brooding items were more predic-
tive of depression than the reflective items, and
brooding appears to explain the sex difference
in depression. Females are more likely than
males to brood, and brooding is associated
with depression (Aldao, Nolen-Hoeksema, &
Schweizer, 2010; Lopez, Driscoll, & Kistner,
2009).
Much of this research is quite compel-
ling because it has been conducted in theM13_HELG0185_04_SE_C13.indd 506 6/21/11 12:55 PM