For many years, scientists struggled to maintain a barrier
between humans and other animals. There
must remain something magical, something inherently superior about humans that
was lacking in lesser beasts. Experiments
and studies were conducted in order to conserve that preconception. But time and a massive tide of new data from a
more recent generation of scientists have begun to wash away that barrier,
revealing that while humans may be superior in some ways, it is by a matter of
degree, not by a fundamental difference. Frans de Waal is one of the scientists who has
been performing the required studies and reporting the results for consumption
by a broad, nontechnical audience. His
most recent effort is titled Mama's Last Hug: Animal Emotions and What They Tell Us about Ourselves. Emotions were once considered an example of a
higher order cognitive response that was available to humans, but largely
lacking in other species. De Waal’s purpose
is to convince us that emotions are not only common among animals, but that
emotional response has been a part of natural selection since quite early in
animal evolution. Human emotional makeup,
and that of a chimp for example, both result from the same evolutionary path that
extended many millions of years into the past.
It was once thought that animal behavior was mainly
instinctual. Certain stimuli produce
certain responses. It only takes a few
minutes of thought to conclude that such a mechanism is insufficient for the
complex environments in which animals live.
De Waal uses as an example a male in search of female with whom to have
sex. When a desirable female is spotted
instinct would tell him to approach and attempt to copulate with her. In a real situation, the female may not be
interested and could violently object to his approach. She may already have a mate who is much
bigger and stronger and might tear him limb from limb. Our instinctive klutz is in need of something
that arouses the desire to mate with a female in sight but provides a mechanism
by which experience and conscious thought can intervene before action is
taken. That is the role emotions have
played in evolution.
“Emotions have the great
advantage over instincts that they don’t dictate specific behavior. Instincts are rigid and reflex-like, which is
not how most animals operate. By
contrast, emotions focus the mind and prepare the body while leaving room for
experience and judgement. They
constitute a flexible response system far and away superior to the instincts. Based on millions of years of evolution, the
emotions ‘know’ things about the environment that we as individuals don’t
always consciously know. This is why the
emotions are said to reflect the wisdom of ages”
De Waal is always pleased to point out that some
emotional response in a human is often reproduced in other species in order to
support the notion that we are all kin.
One example is a fear response in humans that directs the flow of blood
from our extremities to our interior.
This means our extremities get colder when we experience the emotion of
fear. We literally get “cold feet.” The exact same response has been observed in
other apes, and even in rats.
Emotions are intimately coupled with bodily responses,
and body conditions can also affect emotional response. Significantly, emotion is usually expressed
in some visual manner that conveys to an observer knowledge of the emotion
being experienced. This seems to be
purposeful result of natural selection. Humans
are a social animal. It appears
evolution has decided that social animals are more effective as a society if members
have some way of interpreting the emotions other members are experiencing.
Humans have many facial expressions that convey
emotion. Evolution has provided us with the
muscles we can use to produce very nuanced expressions. It was long thought that this presumed unique
complexity was consistent with higher order human intelligence and sociability. However, chimpanzees have the exact same
number of muscles and nearly the same muscular topology as humans.
“When a team of behavioral
scientists and anthropologists finally tested the idea by carefully dissecting the
faces of two dead chimpanzees, they found the exact same number of mimetic
muscles as in the human face—and surprising few differences. We could have predicted this, of course,
because Nikolaas Tulp, the Dutch anatomist immortalized in Rembrandt’s The Anatomy Lesson, had long ago reached
a similar conclusion. In 1641 Tulp was
the first to dissect an ape cadaver and found it resembled the human body so
closely in its structural details, musculature, organs, and so on, that the
species looked like two drops of water.”
Darwin was the first to recognize the similarities in
expressions between humans and other primates.
“We have thus returned to
Charles Darwin’s position in his 1872 book The
Expression of the Emotions in Man and Animals. Darwin stressed that facial expressions are
part of our species repertoire and pointed out similarities with monkeys and
apes, suggesting that all primates have similar emotions. It was a landmark book—acknowledged by
everyone in the field today—but it was the only major book by Darwin that,
after its initial success, was promptly forgotten, then overlooked for almost a
century before we returned to it.
Why? Because hard-core scientists
felt his language was too free and anthropomorphic….Moreover, his suggestion
that we convey our own noble sensibilities through facial movements that we
share with ‘lower’ animals was roundly insulting.”
There now exists much evidence of the fact that facial
expressions are tightly coupled to emotions, that within a species the coupling
is nearly unique, and that human emotional expressions are similar to those of
our primate kin. De Waal refers to the
work of Paul Ekman in categorizing facial expressions.
“Ekman set up controlled tests
with people from more than twenty different nations, showing them pictures of
emotional faces. All these people labeled
human expressions more or less the same way, showing little variation in
recognizing anger, fear, happiness, and so on.
A laugh means the same all over the world.”
To test whether this similarity could have been spread
culturally rather than biologically, Ekman had to test people with little or no
communication with the wider world.
“He travelled to one of the
farthest corners of the planet to administer his tests to a preliterate tribe
in Papua New Guinea. Not only had these
people never heard of John Wayne or Marilyn Monroe, they were unfamiliar with
television and magazines, period. Yet
they still correctly identified most of the emotional faces that Ekman held in
front of them, and they themselves showed no novel, unusual expressions in one
hundred thousand feet of motion pictures of their daily lives.”
There was one more attempt to nail down the biological
nature of emotions and their expression.
“If it is true that the
environment shapes facial expressions, then children who are born blind and
deaf should show no expressions at all, or only strange ones, because they have
never seen the faces of people around them.
Yet in studies of these children, they laugh, smile, and cry in the same
way and under the same circumstances as any typical child. Since their situation excludes learning from
models, how could anyone doubt that emotional expressions are part of biology.”
Given this notion of emotions being biological
constructs, de Wall generalized that finding to conclude that emotions should
be thought of as a body organ. All vertebrates have essentially the same set of
organs, and all are required to function if the specimen is to live. Similarly, emotions have specific functions
and they are necessary for proper functioning.
“First, as we have seen here for
pride, shame, guilt, revenge, gratefulness, forgiveness, hope, and disgust, we
can’t exclude their presence in other species.
These emotions may be more developed in us, or they may be used under a
wider range of circumstances, but they aren’t fundamentally new. That some human cultures emphasize some of
them more than others hardly argues against a biological origin.”
“Second, it is highly unlikely
that any common emotion is functionless.
Given the cost of getting all worked up and passionate about something,
and given how much such states affect decision making, superfluous emotions
would pose an incredible burden. They
might lead us astray, which is certainly not the sort of baggage natural
selection would let us carry. Hence my
proposal that all emotions are both biological and essential. None is more basic than the others, and none
are uniquely human. To me, this is a
logical position given how closely the emotions are tied to the body and how
all mammalian bodies are fundamentally the same. Thus when human subjects were asked to guess
the state of emotional arousal of a variety of reptiles, mammals, amphibians,
and other land animals, just from listening to their calls, they were
remarkably good at doing so. There seem
to exist ‘acoustic universals’ that allow all vertebrates to communicate
emotions in similar ways.”
Discussion of emotions in terms of how we understand them
as humans and how they are also utilized by other animals can be enlightening
as to their functionality. Consider the
role of laughter as an expression of emotional state. It has a definite physical manifestation, and
its basic function is to provide social signals not to enjoy jokes.
“When we laugh, we go
crazy. We become limp, we lean on each
other, we turn red, and we shed tears to the point of dissolving the dividing
line with crying. We literally pee in
our pants! After an evening of laughter,
we are totally exhausted. This is partly
because intense laughter is marked by more exhalations (producing sound) than
inhalations (taking in oxygen) so we end up gasping for air. Laughter is one of the great joys of being
human, with well known health benefits such as stress reduction, stimulation of
heart and lungs, and release of endorphins.”
The social origins of laughter become more apparent when
we observe the role it plays in bonding between parent and infant.
“The earliest laughter in our
lives always occurs in a nurturing context, as it does in the other
primates. A gorilla mother tickles the
belly of her tiny baby with her big finger just a few days after birth,
producing the very first laugh. In our
own species, mothers and babies have lots of exchanges, in which they pay
attention to every shift in each other’s expression and voice, with ample
smiling and laughter.”
Mothers seem peculiarly interested in extracting laughter
and juicy kisses from their infants. The
tickling response is curiously universal in humans and primates (and even in
rats). There must be some evolutionary function
involved that is not obvious in our current human environment.
“Tickling a juvenile chimpanzee
is a lot like tickling a child. The ape
has the same sensitive spots: under the arm pits, on the side, in the
belly. He opens his mouth wide, lips
relaxed, panting audibly in the same familiar huh-huh-huh rhythm of inhalation
and exhalation as human laughter. The
striking similarity makes it hard not to giggle yourself.”
“The ape also shows the same
ambivalence as a child. He pushes your
fingers away, protecting its ticklish spots while trying to escape from you,
but as soon as you stop, he comes back for more, putting his belly right in
front of you. At this point, you need
only point to it, not even touching it, and he will throw another fit of
laughter.”
There is a possible explanation for the importance of
teaching infants to laugh beyond that of bonding with a parent that de Waal
ignores. Humans spent most of their
existence as subsistence hunter-gatherers.
If an infant is to survive it must be able to attract others who would
be willing to care for it while its mother goes about fetching food. A smiling and laughing baby, even in our day,
garners more attention and affection than a crying, unhappy one. Mothers in modern hunter-gatherer societies
have been observed to paint their infants with colorful patterns in hopes of attracting
childcare. Some have even been known to
give their child an enema so the friend providing assistance will not have to
deal with a bowel movement. Chimp
mothers solve the problem by having hairy bodies to which their infants can
cling to while they gather food. But
even chimp mothers will occasionally need assistance from others. Mothers often band together to protect each other’s
children from a male who might want to kill one in order to send the mother
back into estrus so the male can bear an infant of its own. It is always in an infant’s best interest to
generate affection as widely as possible.
All the kissing that mothers like to do with their babies
probably is associated with a deep memory of the time when solid food had to be
prechewed and salivated by the mother and transmitted to the child mouth to
mouth.
Laughter has important social functions that have nothing
to do with humor. The purpose of play in
juveniles is to practice using their bodies and acquire skills that will be
useful in adulthood. Often such skills
involve hunting and taking down prey, so the play can get rough. Such animals develop “play signals” so
actions that appear threatening can be labeled as playful rather than providing
real danger.
“Animal play can be rough, as
players may wrestle, gnaw, jump on top of each other, and drag each other
around. Without an unambiguous signal to
clarify their intentions, play behavior might be mistaken for a fight. Play signals tell others that they have
nothing to worry about, that none of this is serious. For example, dogs may ‘play bow’ (crouch down
on their forelimbs with their butt in the air) to help set play apart from
conflict. But as soon as one dog
misbehaves and accidently bites the other, play ceases abruptly. A new play bow will be required as ‘apology’
so the victim can overlook the offense and resume play.”
“Laughter serves the same
purpose: it puts other behavior into context.
One chimp pushes another firmly to the ground and puts his teeth in her
neck, leaving her no escape, but since both utter a constant stream of hoarse
laughs, they stay totally relaxed. They
know that this is just for fun.”
Laughter serves the same function in playing human children,
but it can also be used to change the context of words and actions in many
social settings.
“…if I approach a colleague and
slap him on the shoulder with a laugh, he will perceive it quite differently
than he would if I did so without a sound or without any expression on my face…Laughing
reframes what we say or do and takes the sting out of potentially offensive
remarks, which is why we use it all the time, even when nothing particularly
amusing is going on.”
“When psychologists
unobtrusively take notes on human behavior in shopping malls and on the
sidewalks of our natural habitat, they find that the majority of laughs occur after
mundane statements that are anything but amusing. Try it yourself. Notice when people laugh in spontaneous
chit-chat, and you’ll see that it’s often about nothing at all—no joke, no pun,
no odd remark. It’s just a laugh
inserted in the flow of conversation, usually echoed by the partner. Humor is not central to laughter: social
relationships are. Our supernoisy, barklike
displays announce mutual liking and well-being.
The laughter of a group of people broadcasts solidarity and
togetherness, not unlike the howling of a pack of wolves.”
“The loud volume of our species’s
laughter gets me every time: apes laugh much more softly, and monkeys can
hardly be heard at all. My guess is that
loudness is inversely proportional to predation risk.”
What is most striking about de Waals numerous discussions
about emotions and emotional responses is that we, and our kin, the primates,
are intensely social animals and our brains and bodies were designed by nature
to help us be a successful social animal.
To be what a libertarian claims to be seems a form of psychopathy, and a
society of libertarians seems a contradiction in terms.
The title of de Waals book is taken from a video of Mama,
an aged ape, who only has a few days left to live. Mama was once the alpha female in a colony of
chimps that lived in captivity. One of
the scientists studying the chimps, Jan van Hooff, had been interacting with Mama
for over forty years. A bond of
affection and friendship had formed between them. The intensity of that relationship became
apparent when van Hooff made a last visit just before she died. On the video it takes Mama a bit of time to
realize that she has a visitor, but when she does, her response is one that is
easily deciphered by we humans. The
video is worth a look. It can be found here.
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