Invitation to Psychology

Chapter 4 Neurons, Hormones, and the Brain 145

Researchers once were convinced that men’s brains

were less lateralized than women’s brains, especially

in tasks involving language. They thought that

women used both sides of the brain when they

were doing a task and men primarily one side. But

meta-analysis and large scale studies have failed to

confirm what “everyone knew” about lateralization

(Chiarello et al., 2009; Sommer et al., 2004, 2008).

Scientists differ in their interpretations of the

sex-differences research in part because some are

focusing on the differences and others are focusing

on the similarities. Yet both groups would agree

that we all should avoid oversimplifying, jumping

to conclusions, and thinking in either–or terms

(either men and women have “different” brains or

we are all exactly alike). Critical-thinking skills are

something the brains of both sexes can acquire.

4

The eternal problem of cause and effect: Some

male-female brain differences could be the result

rather than the cause of behavioral differences. We saw

that culture and experience are constantly sculpting

the circuitry of the brain, affecting the way brains

are organized and how they function. Women and

men, of course, often have different experiences in

childhood and throughout their lives. Thus, when

researchers find a sex difference in brain structure

or function, they cannot automatically assume that

the difference is innate or unchangeable.

5

The elusive brain difference: Now you see it, now

you don’t. Many people tend to think that a

brain is a brain; do a study of six brains, and your

results should generalize to everyone else’s brain.

But research on brains, as on anything else, must be

replicated, and sometimes the results are surprising.

N

ow that you know more about the brain and

nervous system, let’s return to the opening story

about damage to Junior Seau’s brain and the brains of

other athletes who have played fierce contact sports

like football.

Cases like these raise many difficult medical,

psychological, and ethical issues. One is the degree of

risk that individuals and society should tolerate when

damage to this vulnerable organ is a possibility. Of

course, many sports carry some risk of serious injury

and even death: skiing, skydiving, horseback riding,

motorcycling, and especially bicycling (because so

many people don’t wear helmets). But contact sports

such as football, hockey, and boxing are different, be-

cause players may suffer repeated blows to the head

for years, and the effects, though not dramatic at first,

may add up over time.

For any given athlete, it can be difficult to draw

firm conclusions about cause and effect, because other

factors could also account for a player’s subsequent

PsycHology iN tHe News revisited

Recite & Review

Recite: Has your flexible brain absorbed what you’ve just read? Recite out loud everything you

can about plasticity and the effects of experience and maturation on the brain, and what you have

learned about sex-related brain differences.

Review: Next, read this section again.

Now take this Quick Quiz:

1. During childhood, (a) some synapses are strengthened; (b) some synapses weaken and wither
   away; (c) both a and b; (d) neither a nor b.


2. A new study reports that in a sample of 11 brains, 4 of the 6 women’s brains but only 2 of
   the 5 men’s brains had multiple chocolate receptors. (Note: We made this up; there’s no such
   thing as a chocolate receptor—sorry.) The researchers conclude that their findings explain why
   so many women are addicted to chocolate. What concerns should a critical thinker have about
   this study?
   Answers:

Study and Review at mypsychlab

The sample size was small; have the results been replicated? Were the sex differences more impressive than the 2. c1.

similarities? Might eating chocolate affect chocolate receptors rather than the other way around? Most important, was the

number of receptors actually related to the amount of chocolate eaten by the brains’ owners in real life?

118

NEURONS, HORMONES,

AND THE BRAIN

4

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Psychology in the News Revisited

The Nervous System: A Basic Blueprint Communication in the

Mapping the Brain Nervous System^

A the Brain The Tour Through the Brain Two Hemispheres of

The Flexible Brain

T^ Psychology in the News, Revisited^ aking Psychology^ With

Yoinkering Tu: Cosmetic Neurology: With the Brain

long-term players. Concern^ Some health. is have also Several quit growing the well-known sport, among citing players, professional worries such about as footballformertheir^

NFL linebacker Junior Seau committed suicide in 2012. His familyhas filed a wrongful death suit against the league.