Emotion over Logic
Of course, we have all had bad experiences
with attractive people. These encounters reveal a
major weakness in social perception: that preconceived
notions can lead us to poor decisions. We
are seldom aware of these prejudices, however,
which gives them power over us. They are persistent
and hard to overturn. Tania Singer and Joel
S. Winston of the University College Londons
Institute of Neurology reached that conclusion
when they showed test subjects portraits of various
people. Some of the faces elicited immediate
alarms in the amygdalaa structure near the
brains center that is considered the seat of emotion
indicating that the individuals pictured
did not inspire trust. Yet when the subjects
were told later about the good qualities of the
people they had seen, few indicated that the information
changed their initial impression.
Psychologists have been researching social
perception for decades, but it is only recently that
brain imaging and electrical sensing techniques
have begun to elucidate its biological roots. Social
neuroscience is still a young discipline, but
discoveries are helping experts decipher what
makes us judge a stranger as friend or foe.
The effect of this dual processing was tested by
neuropsychologist William A. Cunningham, now
at the University of Toronto, and his colleagues. He
placed each of 15 subjects in a magnetic resonance
imaging machine. To each of them, he read aloud
the names of famous people, such as Bill Cosby,
Yasir Arafat and Mahatma Gandhi. The subjects
were instructed to respond to a neutral question
(Is he alive or dead?) and an emotionally driven
question (Is he a good or bad person?). The
images showed that the subjects answered the
fi rst question with ease. In the second case, Cunningham
observed a considerable increase in the
amygdalas activity, especially in connection with
names that carried negative connotations, such as
Adolf Hitler. Yet the forebrain showed approximately
the same level of activity as it had during the
neutral question, irrespective of whether a name
elicited a positive or negative image. In essence,
the amygdala cast the deciding vote on whether
to declare someone good or evil. Emotional assessment
outranked cognitive assessment.
Among its other duties, the amygdala functions
as a danger detector, activated by potential
threat. Its rapid response can instruct us whether
to react with fi ght or fl ight. In pioneering work in
the 1990s, Joseph LeDoux of New York University
showed that angry human faces elicit stronger
responses in the amygdala than known threats
themselves, such as snakes. Recently Ahmad R.
Hariri of the National Institute of Mental Health
imaged the brains of 28 subjects while they viewed
photographs of faces with angry or fearful expressions.
Hariri also showed them pictures of snakes,
sharks and guns. Both sets of pictures elicited a
signifi cant response in the amygdala, but its reaction
to threatening faces was stronger.
The Social Brain
The more active the amygdala becomes, the
more intense our emotional upheaval and the
more our capacity to reason decreases. Decisions
are made intuitively rather than as a result of rational
assessment.