David Baxter PhD
Late Founder
Evolutionary psychology explores ancient and newer roots of instinctual fears
By Arthur Allen, The Washington Post
Monday, October 25, 2010
Cars kill a lot more people than spiders, bats, snakes and wolves, but why don't we fear them in the same visceral way? When's the last time you saw a jack-o'-lantern carved in the shape of a BMW?
The drugstore Halloween images of dark and hairy critters touch off sensations deep inside us, pointing bony fingers at instincts that go back millions of years, evolutionary psychologists say.
Although some of us fear snakes more than others, all baby humans, chimps and monkeys are equally jumpy when confronted with a black plastic snake. That aversion probably grew out of the pressures of life in the jungle eons ago. Back then, encounters with certain snakes were a matter of life and death, and a healthy fear of snakes kept our ancestors alive long enough to procreate.
In the field of evolutionary psychology, the belief is that instinctive fears became hard-wired in our biology, through genes or other inheritance, during the time (the Stone Age) and place (the African jungle and savannah) of our development into the Homo sapiens we are today.
But some new thinking suggests that these adaptations might date back before the Stone Age, and some, perhaps, to more recent times.
Much of evolutionary psychology is based on hard-to-test hypotheses about the past, which led the late paleontologist Stephen Jay Gould to dismiss the entire field of study as " 'just so' stories." But we aren't interested in the pros and cons of that argument. It's Halloween. Why not delve into the mysterious past with a bit of quavering, Vincent Price-like awe?
H. Stefan Bracha, former director of the Department of Veterans Affairs' post-traumatic stress disorder research center in Honolulu, did so in an article
in the journal Progress in Neuro-Psychopharmacology & Biological Psychiatry.
Over the edge
Bracha's argument is that our mental settings evolved in different phases.
For example, some psychological traits are shared by all mammals. In experiments conducted in the 1960s, baby goats and baby humans were separately offered the opportunity to walk or crawl onto a transparent surface that gave the impression of walking off a cliff. Both declined.
Fear of heights is so widespread and understandable that psychologists consider it a normal fear. The common images of Halloween probably date to a slightly more recent period in evolution. Snakes and spiders killed simians in the African jungles where proto-humans branched off from chimpanzees about 20 million years ago. Another killer was the crocodile, which still hunts chimps in the Congo River basin.
Newborn rhesus monkeys are afraid of toy snakes and toy crocodiles - but not, say, of toy rabbits. Humans have no fear of Twinkies and cheeseburgers - au contraire - although these foods have become more dangerous to our health than anything that skitters, flits or crawls.
"We seem less prepared to develop phobias of things that threaten us in our immediate environment," says O. Joseph Bienvenu, a hospital psychiatrist and researcher at Johns Hopkins University. "You could put a gun in front of a monkey or a baby and they wouldn't go 'Ahhh!' like they would with a plastic snake. We're still catching up, if the evolutionary theories are right, with what we face today."
Addicted to fear
Other phobias that persist into modern times may have been fixed much more recently than snakes and spiders, say in the late Paleolithic age, about 100,000 years ago, or even more recently.
Take fainting in response to seeing blood or surgical instruments. Fainting, Bracha posits, might have been an adaptive female response to the frequent raiding bands in the early hunting-and-gathering societies. You might have been less likely to be murdered if you fainted at the sight of a sharp stick.
Then there are the fears that point to inherently dangerous things and that no doubt have an "adaptive" function, except that they've gotten out of hand. Fears of dirt, rats, mice and insects are obviously self-protective, since all these carry diseases. But most vermin-spread diseases probably were not a serious problem before people began creating cities several thousand years ago.
Instinctual repulsion to some of these critters, Bracha hypothesizes, might have arisen in the Neolithic period, which started about 10,000 years ago.
Sex and violence
So why do some of us appear to be addicted to fear, as evidenced by the popularity of increasingly horrifying horror movies?
And why is it that some of us enjoy these chilling enactments of our ancient fears, while the rest of us would rather eat popcorn in front of anything else, even the Shopping Channel?
If you were a strict evolutionist, you'd say there were adaptive reasons for both horror movie lovers and those who can't stand the stuff.
Psychologists who study personality believe there are certain measures of behavior that are relatively fixed in different people: the degree of extroversion, for example, as well as the degree of neuroticism and openness to new experiences. One area of great variation is the extent to which our happiness depends on new sensations.
"Watching horror movies is a characteristic of the sensation-seeking personality," says Marvin Zuckerman, a professor emeritus of psychology at the University of Delaware.
"They are people who need strong feelings of arousal, and they get those from horror movies as well as sexy movies. Low-sensation-seekers don't like to be aroused by unpleasant things. High-sensation-seekers can enjoy any vicarious experience if it's strong enough."
Humans are the only species that has much variation in risk-taking, Zuckerman said, and he speculates that it has to do with our history.
"We're the only species to emigrate through the entire world and settle in the most inhospitable places," he said. "You take great risks when you emigrate. We hunted large game; a mammoth is a risky proposition. But it's also a great source of protein. The men who hunted mammoths were better providers, more attractive to females. So you can speculate that the guy who brought more meat for the group was more sexually attractive to women, and passed along traits to more offspring. Of course, if you take too many risks, you don't get to propagate your genes."
On the other extreme, Zuckerman says, are the "neophobes" who fear anything new. "That's understandable in evolutionary terms. You stay in the burrow, you stay safe. But you don't get as much food as the ones who explore out there among the predators."
In one experiment, Zuckerman put low- and high-sensation seekers in front of the movie Friday the 13th and measured their physiological fear response through skin tests. In the climactic scene where the monster's bloody head goes flying, low-sensation seekers were more aroused, but to an uncomfortable degree. For the high-sensation seekers, it was exciting, but not that exciting.
Horror and porno movies have gotten more graphic in recent decades to meet the needs of high-sensation seekers, Zuckerman said. "That's an audience that's always looking for something new."
Interestingly, although people with varying levels of some personality traits, such as neuroticism, agreeableness and conscientiousness, intermarry at a seemingly random rate, high-sensation seekers - as well as those on the low end of the sensation-seeking scale - tend to pick similarly arousable people as mates. To the extent that such traits are genetic, rather than learned, they tend to get intensified by this inbreeding. This results in a great range in the population's tolerance of risky behavior.
That's no surprise to those of us with friends who climb mountains, sky-dive, run rapids, take lots of mind-bending chemicals or watch the latest, scariest movies together - while the rest of us shake our heads in disbelief.
By Arthur Allen, The Washington Post
Monday, October 25, 2010
Cars kill a lot more people than spiders, bats, snakes and wolves, but why don't we fear them in the same visceral way? When's the last time you saw a jack-o'-lantern carved in the shape of a BMW?
The drugstore Halloween images of dark and hairy critters touch off sensations deep inside us, pointing bony fingers at instincts that go back millions of years, evolutionary psychologists say.
Although some of us fear snakes more than others, all baby humans, chimps and monkeys are equally jumpy when confronted with a black plastic snake. That aversion probably grew out of the pressures of life in the jungle eons ago. Back then, encounters with certain snakes were a matter of life and death, and a healthy fear of snakes kept our ancestors alive long enough to procreate.
In the field of evolutionary psychology, the belief is that instinctive fears became hard-wired in our biology, through genes or other inheritance, during the time (the Stone Age) and place (the African jungle and savannah) of our development into the Homo sapiens we are today.
But some new thinking suggests that these adaptations might date back before the Stone Age, and some, perhaps, to more recent times.
Much of evolutionary psychology is based on hard-to-test hypotheses about the past, which led the late paleontologist Stephen Jay Gould to dismiss the entire field of study as " 'just so' stories." But we aren't interested in the pros and cons of that argument. It's Halloween. Why not delve into the mysterious past with a bit of quavering, Vincent Price-like awe?
H. Stefan Bracha, former director of the Department of Veterans Affairs' post-traumatic stress disorder research center in Honolulu, did so in an article
in the journal Progress in Neuro-Psychopharmacology & Biological Psychiatry. Over the edge
Bracha's argument is that our mental settings evolved in different phases.
For example, some psychological traits are shared by all mammals. In experiments conducted in the 1960s, baby goats and baby humans were separately offered the opportunity to walk or crawl onto a transparent surface that gave the impression of walking off a cliff. Both declined.
Fear of heights is so widespread and understandable that psychologists consider it a normal fear. The common images of Halloween probably date to a slightly more recent period in evolution. Snakes and spiders killed simians in the African jungles where proto-humans branched off from chimpanzees about 20 million years ago. Another killer was the crocodile, which still hunts chimps in the Congo River basin.
Newborn rhesus monkeys are afraid of toy snakes and toy crocodiles - but not, say, of toy rabbits. Humans have no fear of Twinkies and cheeseburgers - au contraire - although these foods have become more dangerous to our health than anything that skitters, flits or crawls.
"We seem less prepared to develop phobias of things that threaten us in our immediate environment," says O. Joseph Bienvenu, a hospital psychiatrist and researcher at Johns Hopkins University. "You could put a gun in front of a monkey or a baby and they wouldn't go 'Ahhh!' like they would with a plastic snake. We're still catching up, if the evolutionary theories are right, with what we face today."
Addicted to fear
Other phobias that persist into modern times may have been fixed much more recently than snakes and spiders, say in the late Paleolithic age, about 100,000 years ago, or even more recently.
Take fainting in response to seeing blood or surgical instruments. Fainting, Bracha posits, might have been an adaptive female response to the frequent raiding bands in the early hunting-and-gathering societies. You might have been less likely to be murdered if you fainted at the sight of a sharp stick.
Then there are the fears that point to inherently dangerous things and that no doubt have an "adaptive" function, except that they've gotten out of hand. Fears of dirt, rats, mice and insects are obviously self-protective, since all these carry diseases. But most vermin-spread diseases probably were not a serious problem before people began creating cities several thousand years ago.
Instinctual repulsion to some of these critters, Bracha hypothesizes, might have arisen in the Neolithic period, which started about 10,000 years ago.
Sex and violence
So why do some of us appear to be addicted to fear, as evidenced by the popularity of increasingly horrifying horror movies?
And why is it that some of us enjoy these chilling enactments of our ancient fears, while the rest of us would rather eat popcorn in front of anything else, even the Shopping Channel?
If you were a strict evolutionist, you'd say there were adaptive reasons for both horror movie lovers and those who can't stand the stuff.
Psychologists who study personality believe there are certain measures of behavior that are relatively fixed in different people: the degree of extroversion, for example, as well as the degree of neuroticism and openness to new experiences. One area of great variation is the extent to which our happiness depends on new sensations.
"Watching horror movies is a characteristic of the sensation-seeking personality," says Marvin Zuckerman, a professor emeritus of psychology at the University of Delaware.
"They are people who need strong feelings of arousal, and they get those from horror movies as well as sexy movies. Low-sensation-seekers don't like to be aroused by unpleasant things. High-sensation-seekers can enjoy any vicarious experience if it's strong enough."
Humans are the only species that has much variation in risk-taking, Zuckerman said, and he speculates that it has to do with our history.
"We're the only species to emigrate through the entire world and settle in the most inhospitable places," he said. "You take great risks when you emigrate. We hunted large game; a mammoth is a risky proposition. But it's also a great source of protein. The men who hunted mammoths were better providers, more attractive to females. So you can speculate that the guy who brought more meat for the group was more sexually attractive to women, and passed along traits to more offspring. Of course, if you take too many risks, you don't get to propagate your genes."
On the other extreme, Zuckerman says, are the "neophobes" who fear anything new. "That's understandable in evolutionary terms. You stay in the burrow, you stay safe. But you don't get as much food as the ones who explore out there among the predators."
In one experiment, Zuckerman put low- and high-sensation seekers in front of the movie Friday the 13th and measured their physiological fear response through skin tests. In the climactic scene where the monster's bloody head goes flying, low-sensation seekers were more aroused, but to an uncomfortable degree. For the high-sensation seekers, it was exciting, but not that exciting.
Horror and porno movies have gotten more graphic in recent decades to meet the needs of high-sensation seekers, Zuckerman said. "That's an audience that's always looking for something new."
Interestingly, although people with varying levels of some personality traits, such as neuroticism, agreeableness and conscientiousness, intermarry at a seemingly random rate, high-sensation seekers - as well as those on the low end of the sensation-seeking scale - tend to pick similarly arousable people as mates. To the extent that such traits are genetic, rather than learned, they tend to get intensified by this inbreeding. This results in a great range in the population's tolerance of risky behavior.
That's no surprise to those of us with friends who climb mountains, sky-dive, run rapids, take lots of mind-bending chemicals or watch the latest, scariest movies together - while the rest of us shake our heads in disbelief.
