Hemispheric
Specialization I
Goals for Today’s Class:
Understand basic concepts of
neuropsychology
Discuss lateralization/localization of
function in the human brain
Study hemispheric specialization
Lateralization
The two different cerebral hemispheres
(halves of the brain)
DO differ
The hemispheres are
connected via the
corpus callosum
Common Myths
There is a lot of “pop psychology” about
hemispheric specialization
Broad statements like ‘the left brain is
logical and the right brain is creative’ are
almost always gross over-generalizations
The two hemispheres do NOT operate
independently; they communicate
constantly, mostly via the corpus callosum
Lateralization
different
parts of the brain have
different functions
=> localization of function
left
and right hemispheres are
specialized to do different things
=> this is known as lateralization.
contralaterality—the
right half of
your brain controls the left half of
your body and vice versa.
Left visual field (LVF)
Left Hemisphere
Right visual field (RVF)
Right Hemisphere
Some True Differences
Left
Brain
Controls the right
side of the body
Tends to be better
suited for
language
Receives input from
the RIGHT visual
field
Right
Brain
Controls the left
side of the body
Tends to be better
suited to spatial
tasks
Receives input from
the LEFT visual field
Visual Field
R
L
Hemisphere
Function
L
Language
R
Spatial
Tasks
How can we study the differences
between hemispheres?
Cut corpus callosum of severe epileptics
L/R hemispheres will not communicate as
quickly as those in normal people
OR . . .
We could restrict information to either the
left or right hemisphere
Overview of Experiment
Q: is the left hemisphere better-suited for
language processes or not?
Stimuli: 40 words and 40 nonwords
Half of the stimuli are 3 letters long, the
other half 6.
Half of the items are presented to the
LVF/RH and half to the RVF/LH.
Words randomly assigned to conditions.
words(40)
LVF
(10)
3-letters
6-letters
(20)
(20)
RVF
(10)
LVF
(10)
RVF
(10)
non-words(40)
3-letters
(20)
LVF
(10)
RVF
(10)
6-letters
(20)
LVF
(10)
RVF
(10)
Design:
IV1: lexicality
IV2: field of presentation
with 2 levels: word or nonword
with 2 levels: RVF or LVF
IV3: number of letters
with 2 levels: 3- or 6 letters
DV1: reaction time
DV2: error rate in %
Instructions:
to begin a trial press the "space bar".
Focus on X.
respond as fast as possible, but also try to
avoid making errors.
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