The Biological Perspective 83*holistic: relating to or concerned with complete systems or wholes.
Figure 2.16 The Split-Brain Experiment
Building off methods developed by Roger Sperry, Michael Gazzaniga and Joseph LeDoux used this simultaneous
concept test to further investigate functions of the left and right hemispheres of the brain
In a split-brain patient, if a picture of a ball is flashed to the right side of the screen, the
image of the ball will be sent to the left occipital lobe. The person will be able to say that he
or she sees a ball. If a picture of a hammer is flashed to the left side of the screen, the per-
son will not be able to verbally identify the object or be able to state with any certainty that
something was seen. But if the left hand (controlled by the right hemisphere) is used, the per-
son can point to the hammer he or she “didn’t see.” The right occipital lobe clearly saw the
hammer, but the person could not verbalize that fact (Sperry, 1968). By doing studies such as
these, researchers have found that the left hemisphere specializes in language, speech, hand-
writing, calculation (math), sense of time and rhythm (which is mathematical in nature),
and basically any kind of thought requiring analysis. The right hemisphere appears to spe-
cialize in more global (widespread) processing involving perception, visualization, spatial
perception, recognition of patterns, faces, emotions, melodies, and expression of emotions. It
also comprehends simple language but does not produce speech. (See Ta b l e 2. 2 .)
In general, the left hemisphere processes information in a sequence and is good at
breaking things down into smaller parts, or performing analysis (Springer & Deutsch,
1998). The right hemisphere, by contrast, processes information all at once and simulta-
neously, a more global or holistic* style of processing. Remember the discussion in Chap-
ter One of the early days of psychology, the structuralists, and the Gestalt psychologists?
One could almost say that the left hemisphere of the brain is a structuralist who wants to
break everything down into its smallest parts, and the right side of the brain is a Gestalt-
ist, who wants to study only the whole.
So there really are left-brained and right-brained people?Actually, unless one is a split-brain patient, the two sides of the brain are always work-
ing together as an integrated whole. For example, the right side might recognize someone’s
face, while the left side struggles to recall the person’s name. People aren’t really left- or
right-brained, they are “whole-brained.” Michael Gazzaniga was one of Roger Sperry’s stu-
dents, his collaborator, and is a long-time researcher in the area of brain asymmetry and cog-
nitive neuroscience. Gazzaniga’s continuing work in brain lateralization has led to insights
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