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conceptualized as approach emotions (Suberi & McKeever,
1977). Additionally, Reuter-Lorenz and Davidson (1981)
presented subjects with an emotional face and a neutral face
of the same individual simultaneously to each visual field.
Reaction times for identifying happy expressions were faster
during presentation to the right visual field (left
hemisphere) and faster for sad expressions when presented to
the left visual field (right hemisphere). However results
have not been consistently replicated (Duda & Brown, 1984;
McLaren & Bryson, 1987), and the vast majority of studies of
affect perception in normals or focal lesion patients failed
to demonstrate hemisphere-specific valence asymmetries.
Expression of emotion
Many studies of facial expressiveness have found that
the left side of the face is more expressive than the right.
These studies have been interpreted as reflecting a dominant
role of the right hemisphere in emotional expression
(Sackeim & Gur, 1978; Borod, Koff, & White, 1983; Campbell,
1978; Heller & Levy, 1981; Moreno, Borod, Welkowitz, &
Alpert, 1990). However, Schwartz, Ahern, and Brown (1979)
recorded bilateral corrugator and zygomatic EMG during a
mood induction task. They found that subjects expressed
positive emotions more intensely on the right side of the
face and negative emotions on the left side of the face.
However, the majority of research investigating emotional
expressivity in normals and patients with focal lesions