positive event before they experience happiness. An enjoyable conversation or a
favorite song on the radio might be enough to trigger pleasant emotions.
However, subsequent research findings have caused psychologists to re-
think the relationship between cerebral asymmetry and emotions. Instead of
looking at positive and negative emotions, psychologists now describe the differ-
ences in terms of approach and withdrawal tendencies (Harmon-Jones & Allen,
1997; Harmon-Jones & Sigelman, 2001; Pizzagalli, Sherwood, Henriques, &
Davidson, 2005). Studies find that left hemisphere activity is related to move-ment toward the source of the emotion, whereas right hemisphere activity is re-
lated to movement away. Thus higher right hemisphere activity is associated
with sadness because depression is essentially an effort to withdraw from what-ever is causing the emotion. Higher left hemisphere activity is associated with
joy because happiness draws us toward the source of the emotion. Consistent
with this analysis, researchers find that anger is related to higher left hemisphereactivity (Harmon-Jones, Lueck, Fearn, & Harmon-Jones, 2006; Hewig,
Hagemann, Seifert, Naumann, & Bartussek, 2004; Wacker, Chavanon, Leue, &
Stemmler, 2008). Although anger is a negative emotion like depression, angrypeople tend to approach or even attack the source of their distress.
The demonstrated association between cerebral asymmetry and emotion
leads researchers to yet another question: Do differences in hemisphericactivity level play a role in the development of emotional disorders? Some
research findings suggest that they may. Depressed participants in these
studies show more right-side activat ion than nondepressed participants
(Accortt & Allen, 2006; Thibodeau, Jorgensen, & Kim, 2006). In one inves-
tigation, researchers examined EEG patterns in people who were currently
not depressed but who had suffered from previous bouts of depression
(Henriques & Davidson, 1990). These individuals tended to have less
left hemisphere activity in the anterior region of the brain when resting
than a group of participants who had never suffered from depression. Inother words, these previously depressed individuals may have a physiologi-
cally based vulnerability to experience bouts of depression. Other investiga-
tions find anxiety sufferers also have higher right-side activation thannonanxious individuals (Crost, Pauls, & Wacker, 2008; Mathersul,
Williams, Hopkinson, & Kemp, 2008; Thibodeau et al., 2006). Clearly,
whether we suffer from any emotional disorder depends on many factors,including the kinds of experiences we have. But it may be that some people
require fewer or less intense negative experiences than others before suc-
cumbing to feelings of depression or anxiety.
Let’s return now to the eye-drift example at the beginning of this discus-
sion. Although not nearly as reliable as EEG data, research suggests thatright-handed people who typically glance to the left when engaged in reflec-tive thought are likely to show a higher level of right hemisphere activation
when resting. Those who tend to glance to the right are likely to be higher in
left hemisphere activity (Davidson, 1991; Gur & Reivich, 1980). Of course,many other variables affect emotion, but studies suggest that which way you
look during a reflective moment may be a telltale sign of your proclivity to
experience certain emotions.246 CHAPTER 9 The Biological Approach