Department stores opt for nice smells and muzak; impresarios use warm-up
acts. But psychologist Sheila Murphy has an infinitely more devious way of
getting people in the right frame of mind. First she sits them in front of a
screen in her lab at the University of Southern California in Los Angeles. Then
she flashes up images of smiling faces.
Nothing obviously devious about that: smiles make people cheerful. The rub is
that Murphy鈥檚 smiles last for just a few thousandths of a second. That鈥檚 way too
fast for the human brain to know what it鈥檚 looking at. And yet, according to
in-depth studies carried out over many years by Murphy, veteran emotions
researcher Robert Zajonc and their colleagues, these split-second flashes of
teeth and warmly wrinkled eyes induce a measurably more positive frame of
mind.
It sounds crazy. How can people respond to facial expressions too short-lived
to permeate human consciousness? And how can emotions be anything other than
consciously felt and experienced? Welcome to the twilight zone of the human
emotional psyche鈥攖o the curious phenomenon of 鈥渘onconscious affect鈥�, one
of the most hotly debated topics in research on emotions.
Advertisement
A decade ago, the idea of 鈥渘onconscious鈥� human emotions would have cut little
ice in most university psychology departments. The view then was that emotions,
however fleeting, are fuelled by knowledge and thoughts about the world; by the
mind tapping into the cognitive centres of the brain鈥檚 outer layer or cortex. In
the case of responding to a smile, the eyes first send raw visual information to
the back of the cortex. Then the cortex 鈥渃omputes鈥� the fact that there鈥檚 a
smiling face out there. And only then do the emotional circuits of the inner
brain kick in. 鈥淪mile recognition鈥� in the 鈥渢hinking brain鈥� triggers 鈥渟mile
emotion鈥� in the 鈥渇eeling brain鈥�. We think first, feel second. Ergo you cannot
have emotion without cognitive awareness.
But emotion without cognitive awareness is just what Murphy, Zajonc and their
colleagues claim to have uncovered with their subliminal faces. They say it
takes just 4 milliseconds of exposure to a smiling or angry face to produce a
positive or negative reaction in tests on human guinea pigs. Awareness of the
face doesn鈥檛 begin until around 10 milliseconds. As a result, Murphy concludes
that crude, reflex-type emotions can, and do, precede recognition. 鈥淚f you
flashed up a smiling face of Hitler,鈥� she says, 鈥減eople鈥檚 initial gut reactions
might well be positive because of the smile 鈥攂ut they would turn negative
as cognitive awareness of the kind of person who was smiling kicked in.鈥�
Experiments with 鈥渟ubliminal鈥� images are scarcely new. It鈥檚 well known that
people exposed to subliminal images of objects report higher-than-average
鈥渓iking ratings鈥� for the objects afterwards鈥攁lthough they don鈥檛 know why.
But Murphy and her colleagues have gone a step further. They鈥檝e established that
people who are exposed to something like a smiling face tend to feel more
positive about perfectly dull objects they鈥檝e never seen before. The face
triggers what amounts to a superquick 鈥渇eel-good鈥� emotion that spills over to
influence judgment, says Murphy.
Our brains are wired to 鈥渇eel鈥� before they 鈥渢hink鈥�, adds Zajonc鈥攁nd
what they feel in those first few thousandths of a second may influence
subsequent thoughts, even ones that appear rational and emotionless.
None of this applies to complex emotions such as shame, guilt or
embarrassment, all of which depend on knowledge and awareness of situations and
people. What we鈥檙e looking at, says Zajonc, is biology鈥檚 most primal
emotion鈥攖he snap decision to like or dislike, to advance or retreat. It鈥檚
the emotion we share with all sentient creatures, and one that鈥檚 triggered so
fast and easily in the brain that it precedes all thought and awareness of
whatever it is in the environment that鈥檚 pulling the trigger.
Until a few years ago, such ideas sat uneasily with what we knew about the
structure of the brain. But not now鈥攖hanks mainly to some ground-breaking
research into a small structure in the mid-brain called the amygdala.
Certainly, the amygdala seems well placed in the 鈥渘onconscious鈥� brain to
react fast鈥攁nd emotionally鈥攖o external events. A bundle of nerve
connections to the brain stem lets the amygdala prime the body for 鈥渇ight or
flight鈥�. And Joseph LeDoux鈥檚 team at New York University in New York have
discovered a nerve pathway in lab rats which enables the amygdala to gain rapid
access to raw, unprocessed information from the eyes and ears. The result, says
LeDoux, is an 鈥渁ct now, think later鈥� alarm system that makes perfect
evolutionary sense: you don鈥檛 need to assemble a complete mental picture of the
long, thin snake-like thing in the grass to beat a speedy retreat.
In fact, the amygdala鈥檚 role in our emotional lives may be even bigger than
that. LeDoux鈥檚 latest research shows that its neural circuits are capable of
鈥渓earning鈥� from experience: might they be the neural repository of some of
life鈥檚 great emotional lessons? And people with damaged amygdalas often lack one
or more emotional skills that the rest of us take for granted鈥攕uch as
being able to read emotions in faces, for example.
Striking evidence of the amygdala鈥檚 role in human fears and anxieties is also
emerging from brain imaging labs. Later this year, Richard Davidson, an emotions
researcher at the University of Wisconsin, in Madison, will publish his team鈥檚
data showing that when people are exposed to disturbing images, the amygdala
lights up on cue. What鈥檚 more, says Davidson, natural worriers or depressives
have unusually active amygdalas, compared to those of stoical types. The
worriers鈥� fear sentinels seem to be that much readier to sound the alarm.
Most of us are plainly not in the thrall of the lightning-fast fear reflexes
of the primitive inner brain. Conscious thought and will-power can, and do,
intervene to police these reflexes. When things go bump in the night, we console
ourselves with thoughts of clunky central heating systems.
Even so, no amount of stoicism or cortical activity can quench all the
reflex-type reactions that go to make an emotion. And if Zajonc and Murphy are
right, that includes the first few milliseconds of our most basic emotional
reactions. Does this mean there鈥檚 a definable portion of our emotional lives for
which we cannot or should not be held morally responsible? That鈥檚 one for
philosophers to take up, but Zajonc is at least certain about one thing:
鈥淓motion paves the pathway for cognition; if it didn鈥檛 we鈥檇 have all been bitten
by the snakes long ago.鈥�
