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right hemisphere is involved in interpreting emotional
stimuli and has a unique relationship to subcortical
structures which mediate cerebral arousal and activation
(e.g., Heilman, Watson, & Bowers, 1983). Consequently,
damage in the right hemisphere interferes with processing
emotional stimuli, programs of expressive behavior, and
cerebral arousal and activation. In contrast, the bivalent
view of emotion posits that the anterior portion of the
right hemisphere is dominant for negative/avoidance emotions
and the anterior region of the left hemisphere is dominant
for positive/approach emotions (e.g., Fox & Davidson, 1984).
According to the bivalent view, right hemisphere damage
causes positive/approach affect and left hemisphere damage
evokes negative/avoidance affect. Both models and the
empirical research in support of each are discussed below.
Global Theory of Emotion
According to the global right hemisphere model,
observations of emotional indifference in RHD patients can
be explained by the right hemisphere's specialization for
coding nonverbal affective signals and mediating arousal and
activation (Heilman et al., 1983). The global right
hemisphere theory is supported by research exploring
emotional evaluation, expression, and arousal/activation,
which has revealed that RHD patients are deficient in
interpretation of emotional stimuli, are emotionally