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Stressed Out
Happiness, sadness, anger, fear, love, hate -- emotions play a pivotal role
in our lives. But do they loom large in an animal's world as well? Part
Two of NATURE's INSIDE THE ANIMAL MIND explores
that question in fascinating detail.
Like humans, baboons harass each other, compete for rank, and undergo stress. |
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In large part, researchers have found that emotions are accompanied by
biochemical changes in the brain. Fear, for instance, is accompanied by
the production of one set of brain chemicals that can make us alert and
ready to flee, while pleasure triggers the release of other chemicals
that soothe and calm. But some emotions aren't so biologically clear-cut.
Shame, for instance, is a so-called "social emotion," the product of attaching
an emotional meaning to a behavior, such as hitting another person, or
lying, that may be appropriate in one social setting but out of bounds
in another.
While researchers don't agree on how big a role such social emotions play
in the animal world, there is widespread agreement that many animals share
another emotional characteristic with us: stress. Indeed, like humans, many
animals can be harried and "stressed out" -- with sometimes serious health
consequences.
 Among the most remarkable studies of stress in animals are those carried
out on African baboons by Stanford University research Robert Sapolsky
and his colleagues. For three months each year, Sapolsky travels to East
Africa's Serengeti plain to examine how factors like a baboon's social
behavior, personality, and rank within its troop influence the levels
of stress hormones produced by the ape. By measuring the hormones found
in each individual's feces, Sapolsky's team has been able to show that
baboon troops are high-stress societies, with higher-ranked individuals
maintaining order by intimidating lower-ranked troopmates. Indeed, Sapolsky
says, "Baboons and us are surprisingly similar . . . they can devote a
large part of each day to making each other absolutely miserable with
social stress."
Sapolsky's team has also shown that such stress can have real health
consequences. Stressed-out mothers, for instance, have more problems producing
healthy offspring. And sustained production of stress hormones can also
damage the hippocampus, a region of the brain central to learning and
memory. So even though baboons may not commute, do their bosses' dry cleaning,
or pay income taxes, they suffer very similarly from the scourge of stress.
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