Invitation to Psychology

132 Chapter 4 Neurons, Hormones, and the Brain

poor definitions of the behavior being studied,

and inappropriate interpretations of results. For

example, the enthusiasm for technology has gen-

erated the widespread belief that specific “brain

centers” or “critical circuits” explain why you

prefer Coke to Pepsi, why you identify as a lib-

eral or conservative, or what your brain is doing

when you are in love. These beliefs are appealing

because they seem to explain complicated behav-

ior in simple terms (Beck, 2010). But attempts to

reduce complex behavior to single locations will

almost certainly fail (Gonsalves & Cohen, 2010;

Tallis, 2011; Uttal, 2011). At present, technology

is better at telling us where things happen than

why or how they happen. So if you know that one

part of the brain is activated when you are think-

ing hot thoughts of your beloved, what exactly do

you know about love—or your brain? Does that

part also light up when you are looking at other

things that you love, such as a luscious hot fudge

sundae, or thinking about happily riding your

horse Horace through the hills? Do other parts

become active, too? As neuroscientist Raymond

Tallis (2011) noted, love is not a single state, like

being cold; it includes many emotions, from desire

to jealousy to quiet contentment, and sometimes

several conflicting emotions at the same time.

Nonetheless, when used appropriately, these

measures do provide an illuminating look at the

brain during work and play, and we will be report-

ing many findings based on brain scan research

throughout this book. The brain can no lon-

ger hide from researchers behind the fortress of

the skull.

Moreover, research using fMRI has some-

times suffered from questionable statistical

procedures that have produced highly inflated

correlations between brain activity and measures

of personality and emotion (Vul et al., 2009).

Yet the media usually

report these findings

uncritically, giving

the impression that

scientists know more

about the relation-

ship between the

brain and psycho-

logical processes than they really do (McCabe &

Castell, 2008).

To illustrate this point, a clever group of scien-

tists did an fMRI on a dead salmon (yes, you read

that right) while asking it to view emotional images

and determine what emotions the person in each

photo was feeling (Bennett et al., 2010). You’re

probably wondering why the fMRI would detect any

brain activity in a dead salmon, but it did. The scan

appeared to show that the salmon was “thinking”

about the pictures and the people in them. That was

because fMRI produces a mix of signal and noise;

picking up the signal is like trying to track a conver-

sation in a crowded bar. Scientists must use sophis-

ticated techniques to filter out the noise and reveal

the true signal, and if they don’t know what they are

doing, they can make errors. In this case, the result

is funny, but in real life, too, we may not know if the

result is real ... or another dead salmon.

The problem is not with technology per se

so much as it is with faulty analyses or theories,

About Brain-Scan

Technology

Thinking

CriTiCally

Recite & Review

Recite: You know the drill: Tell someone or something everything you can recall about transcranial

magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), EEGs, PET scans, MRI,

fMRI, and ... the dead salmon.

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

Now take this Quick Quiz:

1. What two methods can be used to temporarily disrupt neural activity in an area of the brain?


2. What does fMRI tells us that ordinary MRI does not?


3. A researcher scans the brains of gum-chewing volunteers, finds out which part of their brains
   is most active, and announces the discovery of the brain’s “gum-chewing center.” What’s
   wrong with this conclusion?
   Answers:

Study and Review at mypsychlab

An fMRI allows us to associate brain activity with specific thoughts or behaviors lasting at least several 2. TMS and tDCS.1.

Many actions and sensations are involved in chewing gum, 3. seconds, instead of just picturing the brain at a moment in time.

such as the chewing motion, enjoyment of the flavors, and salivation. A brain scan may tell us where things are happening but

not why or how they are happening. The same areas might also become active when you chew a piece of asparagus. Finally,

even if there were a gum-chewing center (there isn’t!), yours might not be in the same place as someone else’s. Brains vary, a

fact that may be lost when a researcher averages the results of all the brain scans in his or her study.