Invitation to Psychology

Chapter 4 Neurons, Hormones, and the Brain 141

activities, the two sides cooperate naturally, with

each making a valuable contribution. In visual

perception, the left side generally “sees” the de-

tails and the right hemisphere “sees” how they fit

together (Robertson, Lamb, & Knight, 1988). In

speech perception, the left hemisphere “hears” the

individual sounds that make up the words and the

right hemisphere “hears” the intonation that tells

us if the speaker is happy, sad, or sarcastic. Be cau-

tious, then, about thinking of the two sides as two

“minds.” As Sperry

(1982) himself noted

long ago, “The left–

right dichotomy ...

is an idea with which

it is very easy to

run wild.”

described previously, researchers can find out if
one hemisphere has a small “head start” before
the corpus callosum transfers information about
an image or a sound to the other hemisphere. The
results confirm that nearly all right-handed people
and a majority of left-handers process language
mainly in the left hemisphere. The left side is also
more active during some logical, symbolic, and se-
quential tasks, such as solving math problems and
understanding technical material.
In part because of the left hemisphere’s lin-
guistic and analytic talents, early researchers often
spoke of the left hemisphere as dominant. But to-
day we know that the right hemisphere is far from
stupid or passive. It is superior at recognizing
facial expressions and also at handling problems
requiring spatial-visual abilities, such as reading
a map or following a dress pattern. It is active
during the creation and appreciation of art and
music. It recognizes nonverbal sounds, such as a
dog’s barking. It also has some language ability.
Typically, it can read a word briefly flashed to it
and can understand an experimenter’s instructions.
Some researchers have also credited the right
hemisphere with having a cognitive style that is
intuitive and holistic, in contrast to the left hemi-
sphere’s more rational and analytic mode. This
idea has been oversold by books and programs
that promise to make people more creative by
making them more “right-brained.” In reality,
the differences between the two hemispheres are
relative, not absolute—a matter of degree. In most

About Right Brain/Left

Brain Theories

Thinking

CriTiCally

Recite & Review

Recite: Say aloud everything you can about split-brain surgery and the activities of the right and

left hemispheres.

Review: Next, go back and read this section again.

Now use as many parts of your brain as necessary to take this Quick Quiz:

1. Bearing in mind that both sides of the brain are involved in most activities, identify which of
   the following is (are) more closely associated with the left hemisphere: (a) enjoying a musical
   recording, (b) wiggling the left big toe, (c) giving a speech in class, (d) balancing a checkbook,
   (e) recognizing a long-lost friend.


2. Which hemisphere is sometimes called an “interpreter,” and why?


3. Thousands of people have taken courses and bought books that promise to develop the
   creativity and intuition of their right hemispheres. What characteristics of human thought
   might explain the eagerness of some people to glorify “right-brainedness” and disparage
   “left-brainedness” (or vice versa)?
   Answers:

Study and Review at mypsychlab

One possible answer: Human 3. The left, because it provides explanations of our thoughts, feelings, and behavior.2. c, d1.

beings like to make sense of the world, and one easy way to do that is to divide humanity into opposing categories. This kind of

either–or thinking can lead to the conclusion that fixing up one brain hemisphere (for example, making “left-brained” types more

“right-brained”) will make individuals happier and the world a better place. If only it were that simple!

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