ChapTER 13 Emotion, Stress, and Health 453of your control. In a sense, you are out of control
because you cannot consciously alter your heart
rate and blood pressure. However, you can learn to
control your actions when you are under the sway
of an emotion (even intense anger, as we discuss
in “Taking Psychology With You”). Eventually, as
arousal subsides, anger may pale into annoyance,
ecstasy into contentment, fear into suspicion, past
emotional whirlwinds into calm breezes.
In sum, the physiology of emotion involves
characteristic facial expressions; activity in specific
parts of the brain, notably the amygdala, special
ized parts of the prefrontal cortex, and mirror
neurons; and sympathetic nervous system activity
that prepares the body for action.Biology and Deception: Can Lies Be Detected
in the Brain and Body? Social scientists, gov
ernments, and police officers yearn to be able to
detect liars without falsely accusing truth tellers.
Unfortunately, even highly educated and trained
individuals have only about a 54 percent chance of
detecting a lie (Bond & DePaulo, 2008). For the
rest of us, the success rate is 50 percent, no better
than flipping a coin. People may speak hesitantly
in telling a story, seem stressed in their speech, or
avoid looking the interrogator in the eye for many
reasons (DePaulo et al., 2003; Leo, 2008; Vrij,
Granhag, & Porter, 2010). They may be frightened,
not know what answers are expected, have nervous
mannerisms, or come from a culture that regards
direct eye contact as confrontational or rude.
For centuries, people have tried to determine
when a person is lying by detecting physiological
responses that cannot be controlled consciously.
This is the idea behind the polygraph machine
(lie detector), which is based on the assump
tion that a lie generates emotional arousal. A
person who is guilty and fearful of being foundfeeling vaguely depressed yourself? Have you ever
stopped to have a chat with a friend who was ner
vous about an upcoming exam and ended up feel
ing edgy yourself? That’s mood contagion at work.
Mood contagion also occurs when two people
are influenced by one another’s positive emo
tions, nonverbal signals, and posture: Their ges
tures become more synchronized, they behave
more cooperatively, and they feel more cheerful
(Wiltermuth & Heath, 2009). This phenome
non may be the reason that synchronized human
activities—marches, bands, dancing—are socially
and emotionally beneficial as well as exciting.
The Energy of Emotion. LO 13.5 Once the brain
areas associated with emotion are activated, the
next stage is the release of hormones to enable you
to respond quickly. When you are under stress or
feeling an intense emotion, the sympathetic division
of the autonomic nervous system spurs the adrenal
glands to send out epinephrine and norepinephrine
(see Chapter 4). These chemical messengers pro
duce arousal and alertness. The pupils dilate, wid
ening to allow in more light; the heart beats faster,
blood pressure increases, breathing speeds up, and
blood sugar rises. These changes provide the body
with the energy needed to take action, whether you
are happy and want to get close to someone you
love, or are scared and want to escape a person who
is frightening you (Löw et al., 2008). All emotions
share a neural circuitry that affects the degree of
arousal (how intensely you experience an emotion)
and subjective ratings of how pleasant or unpleas
ant the feeling is (WilsonMendenhall, Barrett, &
Barsalou, 2013).
Epinephrine in particular provides the energy
of an emotion, that familiar tingle of excitement.
At high levels, it can create the sensation of being
“seized” or “flooded” by an emotion that is out
These volunteers, videotaped in a study of conversational synchrony, are obviously in sync with each other, even
though they have just met. The degree to which two people’s gestures and expressions are synchronized increases the
rapport they feel with one another (Grahe & Bernieri, 1999).