Animals in Translation (11 page)

Some researchers say that people like Holly have
developed
super-sensitive hearing because their visual processing is so scrambled. Super-sensitive hearing is a compensation, in other words. That's always the explanation researchers give for the super-hearing of blind people; people who are blind have built up their hearing to compensate for not being able to see.

I'm sure that's true, but I don't think it's the whole story. I think the potential to be able to hear the radio when it's turned off is
already there
inside everyone's brains; we just can't access it. Somehow a person with sensory problems figures out how to get to it.

I have two reasons for thinking this. First, there are a lot of cases in the literature of people suddenly developing extreme perception after a head injury. In
The Man Who Mistook His Wife for a Hat
Oliver Sacks has a story about a medical student who was taking a lot of recreational drugs (mostly amphetamines). One night he dreamed that he was a dog. When he woke up he found that all of a sudden, literally overnight, he had developed super-heightened perceptions, including a heightened sense of smell. When he went to his clinic, he recognized all twenty of his patients, before he saw them,
purely by smell.
He said he could smell their emotions, too, which is something people have always suspected dogs can do. He could recognize every single street and shop in New York City by smell, and he felt a strong impulse to sniff and touch things.
¹³

His color perception was much more vivid, too. All of a sudden he could see dozens of shades of colors he'd never seen before—dozens of shades of the color brown, for instance.

This happened overnight. It's not like he lost some other sense and then built up his sense of smell over time to compensate. He dreamed he was a dog and the next morning woke up able to smell things like a dog. The actor Christopher Reeve had a similar experience right after his accident. All of a sudden he had an incredibly heightened sense of smell.

The other important thing to know about this guy is that he hadn't had any big brain injury that anyone knew about. Dr. Sacks
assumes that the heavy drug usage was probably the cause, but there's no way of knowing. The student continued to function in medical school just fine, and his vision and sense of smell went back to normal about three weeks later. Of course, some part of his brain could have been temporarily incapacitated, but if it was, there's no obvious way that being able to smell people the way a dog smells people helped him compensate for whatever might have been wrong. The most likely explanation is that he always had an ability to smell like a dog and see fifty different shades of brown, but he just didn't know it and couldn't access it. Somehow his heavy amphetamine usage must have opened up the door to that part of his brain.

My other reason for thinking everyone has the potential for extreme perception is the fact that animals have extreme perception, and people have animal brains. People use their animal brains all day long, but the difference is that people
aren't conscious of what's in them.
We'll talk about this in the last chapter. A lot of what animals see normal people see, too, but normal people don't know they're seeing it. Instead, a normal person's brain uses the detailed raw data of the world to form a generalized concept or schema, and that's what reaches consciousness. Fifty shades of brown turn into just one unified color: brown. That's why normal people see only what they expect to see—because they can't
consciously experience
the raw data, only the schema their brains create out of the raw data.

Normal people see and hear schemas, not raw sensory data.

I can't prove that humans are taking in the same things animals are, but we do have proof that humans are taking in way more sensory data than they realize. That's one of the major findings of the inattentional blindness research. It's not that normal people don't see the lady dressed in a gorilla suit at all; it's that their brains screen her out before she reaches consciousness.

We know people see things they don't know they see because of years of research into areas like
implicit cognition
and
subliminal perception.
Dr. Mack and Dr. Rock, who wrote
Inattentional Blindness,
adapted some of these studies for their inattentional blindness research. They'd do things like ask their subjects to tell them which arm of a cross that flashed onto a computer screen for about 200
milliseconds was longer. Then, on some of the trials, there'd be a word like “grace” or “flake” printed on the screen, too. Most people didn't notice the word. They were paying attention to the cross, so they didn't see it.
¹⁴

But Dr. Rock and Dr. Mack showed that many of them
had
seen the words unconsciously. Later on, when they gave subjects just the first three letters of the word—
gra
or
fla
—and asked them to finish them with any word that came to mind, 36 percent answered “grace” or “flake.” Only 4 percent of the control subjects—these were people who hadn't been subliminally exposed to any words at all—came up with “grace” or “flake.” That's a huge difference and can only mean that the subjects who were subliminally exposed to “grace” and “flake” really did see “grace” and “flake.” They just didn't know it.

So we know that people perceive lots more than they realize consciously. Drs. Rock and Mack say that inattentional blindness works at a
high level of mental processing,
meaning that your brain does a lot of processing before it allows something into consciousness. In a normal human brain sensory data comes in, your brain figures out what it is, and only then does it decide whether to tell you about it, depending on how important it is. A lot of processing has already taken place before a normal human becomes conscious of something in the environment. (Drs. Rock and Mack use the phrase
high level
to mean advanced
processing,
not necessarily higher levels of the brain. They don't discuss neuropsychology, just cognitive psychology.)

There are a few things that always
do
break through to consciousness. I mentioned that people almost always notice their names in the middle of a page of text no matter how hard they're concentrating on something else; they will also notice a cartoon smiley face. But if you change the face just a tiny bit—turn the smile upside down so it's a frown, for instance—people don't see it. This is more evidence for the fact that your brain thoroughly processes sensory data before allowing it to become conscious. With the smiley face your brain has to have processed it to the level of knowing it's a face and even that it's a
smiling
face before it lets the face into conscious perception. Otherwise you'd see the frowny face as often as you saw the smiley face. It's the same principle with your name. If your name is “Jack,” the word “Jack” will pop out at you in the middle of a
page. But the letters “Jick” won't. That means your brain processes the word “Jack” all the way up to the level of knowing that it's your name before your brain admits “Jack” into consciousness.

We don't know why humans have inattentional blindness. Maybe inattentional blindness is the brain's way of filtering out distractions. If you're trying to watch a basketball game and a lady gorilla comes into view, your brain screens her out because she's not supposed to be there, and she's not relevant to what you're trying to do, which is watch a game. Your nonconscious brain takes a look at the lady gorilla and decides she's a distraction.

Being able to filter out distractions is a good thing; just ask anyone who can't filter things out, like a person with
attention deficit hyperactivity disorder.
It's hard for humans to function intellectually when every little sensory detail in their environment keeps hijacking their attention. You go into information overload.

But humans probably paid a price for developing the ability to filter out ladies wearing gorilla suits, which is that normal people can't
not
filter out distractions. A normal brain automatically filters out irrelevant details, whether you want it to or not. You can't just tell your brain: be sure and let me know if anything out of the ordinary pops up. It doesn't work that way.

Autistic people and animals are different: we can't filter stuff out. All the zillions and zillions of sensory details in the world come into our conscious awareness, and we get overwhelmed. There's no way to know exactly
how
close an autistic person's sensory perceptions are to an animal's. There are probably some big differences, if only for the reason that animal perceptions are normal for animals, while autistic people's perceptions are
not
normal for people.

But I think many or even most autistic people experience the world a lot the way animals experience the world: as a swirling mass of tiny details. We're seeing, hearing, and feeling all the things no one else can.

R
APIST
R
OOSTERS

W
e've been doing some strange things to animals' emotional makeup in our breeding programs. When I was just starting my work with chickens a few years ago, I visited a chicken farm. Inside the barn where all the chickens lived I found a dead hen lying there on the floor. She was all cut up, and her body was fresh. I was horrified.

I went back to the farmer and I said,
“What
was
that?”

He told me the rooster did it: the rooster killed the hen. He acted like that was a perfectly normal thing for a rooster to do. He wasn't happy that his roosters were killing his hens; he just thought that's the way it was.

I knew that couldn't be right. If roosters killed hens in nature, there wouldn't be any chickens. But people raising animals in captivity tend to forget this basic fact of life. A lady who raises llamas told me recently that one of her males had tried to bite the testicles off another male. I told her that's definitely not normal. If llamas bit off each other's testicles in the wild there wouldn't be any llamas.

The chicken farmer told me that
half
of his roosters were rapist-murderers. I was stunned when I heard that. There is no species alive in nature where half the males kill reproductive-age females. There had to be something seriously wrong with those birds.

So when I got home I immediately talked to one of my students whose family were backyard breeders. They had a small side business raising and breeding chickens in the backyard. She'd never even heard of a rooster killing a hen. Then I called my good friend Tina Widowski, who was a specialist in chickens, and she said absolutely not: normal roosters do not kill hens.

Tina knew about the killer roosters, and she told me what the deal was. Ian Duncan from the University of Guelph in Canada had studied the roosters and had found that the rooster courtship program had gotten accidentally deleted in about half of the birds. A normal rooster does a little courtship dance before trying to mate with a hen. The dance is hardwired into the rooster's brain; it is instinctual behavior, or what animal ethologists call a
fixed action pattern.
All normal roosters do it.

The dance triggers a fixed action pattern in the hen's brain, and she crouches down into a sexually receptive position so the rooster can mount her.
She doesn't crouch down unless she sees the dance.
That's the way her brain is wired.

But half of the roosters had stopped doing the dance, which meant that the hens had stopped crouching down for them. So the roosters had become rapists. They jumped on the hens and tried to mate them by force, and when the hen tried to get away, the rooster would attack her with his spurs or his toes and slash her to death.

S
INGLE
-T
RAIT
B
REEDING

The rapist roosters were a side effect of
single-trait breeding,
which is selectively breeding animals to increase or decrease just one or two desirable traits, like fast growth (to decrease feed costs and time to market) or heavy muscling (to increase the amount of meat per bird). The breeders focus totally on those traits and nothing else.

Single-trait breeding isn't quite as simple as just mating fast-growing, big-muscled males to fast-growing, big-muscled females, because when you do that fertility tends to go out the window. You get animals who have trouble reproducing themselves. So breeders mate females who have fast growth, big muscles,
and
sound fertility to males who just have fast growth and big muscles. They don't worry about fertility levels in the males, because even a low-fertility male can still fertilize the eggs of a female with good fertility. You end up with a
hybrid
chicken, which means a cross between two different lines. All of the chicken meat and eggs we eat come from hybrid birds.

Single-trait breeding works fast in chickens because their repro
ductive cycle is so short. A chicken egg has to be incubated for only twenty-one days before it hatches, and a newly hatched female chick will be ready to lay fertile eggs five months later. That's two generations of chickens in one year, which means that in three to five years the genetic line can be changed completely.

The problem with single-trait breeding is that when you breed for one trait you end up changing other traits, too: there are always unintended consequences. That's what happened with the roosters.

The rapist roosters didn't come along until breeders had gone through at least three different single-trait breeding programs over a number of years. The first goal the industry pursued was to develop faster-growing chickens who could be taken to market sooner. They mated the fastest-growing hens with the fastest-growing roosters and voilà: faster-growing chickens. In practice it's more complicated than this, because they also do various genetic calculations, but the basic approach is to breed
fast
to
fast.

Like every single-trait breeding program, this one had some unintended consequences although they weren't as severe as the rapist roosters. Mainly the faster-growing chickens tended to have weaker legs and hearts. The weak hearts meant a higher incidence of
flip-over disease,
which is a nice way of saying that the chickens' hearts gave out. Heart failure in chickens got the name flip-over disease because that's what it looks like. When a chicken has heart failure it suddenly flips over and dies.

The next goal was to breed chickens with bigger breasts because people like to eat white meat. That program was successful, too; they got chickens with bigger breasts. This time they got a lot more problems, though, because the chickens grew so big that their legs couldn't handle their weight. Many of the chickens were so lame they couldn't walk to the feeder, and some of their legs were deformed and bent, with fluid-filled swellings.

The chickens were probably in constant pain. One study found that the lame chickens would choose to eat bad-tasting feed laced with painkillers over normal-tasting feed, which is good evidence that the chickens were suffering.

They also had a much higher rate of flip-over disease, because their hearts were too small to pump blood to their huge bodies. It
was like trying to run a Mack truck on a Volkswagen engine, and their hearts gave out.

The big-breasted chickens were a disaster. No one wants to breed chickens who are lame and in pain, but even if you didn't care about the chickens' well-being, no business can sell deformed drumsticks to the food market. They had to do something, so they started breeding for strength and
livability,
which means the chickens' overall health and ability to grow and thrive instead of dying young.

They didn't just go backward a step to the earlier chickens with the smaller breasts, because they wanted to have their cake and eat it, too. They wanted fast-growing, big-breasted chickens with strong legs and sound hearts. Breeder colonies think like software companies. If there are problems with Chicken 3.2 they don't go back to Chicken 3.1. They go forward to 3.3.

So in another few years they had big, strong chickens with big, heavy thick legs and stronger hearts and it looked like they had their dream chicken. Then nature threw them a curveball and they got raping, murdering roosters. No one has any idea why or how the genes for hearts and bones are related to the genes for mating behavior, but obviously they are.

This kind of thing happens all the time when breeders over-select for a single trait. You get warped evolution.

The really bad thing was that the change happened slowly enough that the farmers and probably the breeder colonies, too, didn't realize they'd created a monster. Nobody noticed what was happening. As the roosters got more and more aggressive, the humans unconsciously adjusted their perceptions of how a normal rooster should act. It was a case of
the bad becoming normal,
and it's a big danger in selective breeding programs. I've seen it many times.

S
ELECTION
P
RESSURE

Human beings are constantly changing the
selection pressure
on animals, whether we want to or not. Selection pressure is the term for what happens when the environment influences or
selects
which members of a species live long enough to reproduce successfully and which do not. Selection pressure can help new traits get stronger
and more widespread in a species, and the absence of selection pressure can cause long-standing traits to weaken or disappear.

That's what happened with the Old World primates. They probably experienced some kind of random genetic mutation that gave them better color vision; then their improved color vision was so useful for finding food that the animals with the best color vision also had the best chance of staying alive long enough to reproduce. After their babies were born, of course, the trichromatic vision animals would also have had the best chance of finding enough food to feed their offspring, so the babies—many or most of whom would have inherited the new trichromatic vision mutation—also lived to adulthood and reproduced. That's how selection pressure strengthens a trait; it gives animals who have the trait a reproductive advantage. Over succeeding generations their genes spread through the population.

At the same time, once vision became
more
important for finding food, smell probably became
less
important. This would have meant that animals with an excellent sense of smell were no more likely to have babies than animals with a poor sense of smell: everyone could reproduce no matter how good or bad their sense of smell. The selection pressure for good smell genes was gone.

As a direct result, Old World primates' sense of smell would have gone into decline. Genetic mutations happen all the time when animals reproduce, due to simple copying errors in the DNA. Some mutations are good, some are bad, and some don't make a difference one way or another. Selection pressure saves and promotes the good mutations and weeds out the bad ones. Once selection pressure is gone, a trait will go into decline through the natural process of routine genetic mutations piling up on each other until the trait or traits those genes influence has weakened or even disappeared.

T
HE
B
AD
B
ECOMES
N
ORMAL

When it comes to domestic animals,
we're the environment.
We create the selection pressures. If you're a chicken breeder and you allow only the fastest-growing roosters and hens to breed you're exerting a selection pressure in favor of faster-growing chickens.

That's an example of an intentional selection pressure, but people
create unconscious, accidental selection pressures all the time. For instance, you've probably heard doctors complain about patients not finishing their full course of antibiotics. The reason you're supposed to finish your antibiotics is that when you don't, you're unintentionally creating a selection pressure that favors the development of antibiotic-resistant strains. That's because you've used a half-course of antibiotics to kill off the weaker bacteria, leaving only the stronger bacteria alive to reproduce. Over several generations, that's how you get bugs that antibiotics can't kill.

With domestic animals, we are the main engine of evolution. We're constantly changing their bodies and their emotions, and it happens a lot faster than we realize. The most interesting study of this was one where the researchers gave rats from the same genetic strain to two different labs and then left them there for five years while the labs did all their normal experiments. Both of the labs bred successor generations from the original rats, which meant that researchers could compare the descendants.

At the end of five years, the researchers tested the rats and found that the two groups of descendants had developed completely different levels of natural fear. They tested this by doing
open arena
studies with each rat. In an open arena study you put one rat alone inside a well-lit open space about the size of a large tabletop, and watch to see how much exploring he does. Being prey animals, mice and rats don't like open, well-lit spaces. Only the boldest rat will do much exploring out in the open; most rats hang back at the sides of the arena and stay still.

The ancestor rats had all started out with exactly the same levels of exploratory behavior. But at the end of just five years, one group of descendant rats was much more fearful than the other.

The interesting thing was that none of the people at the labs had any idea their rats had changed, and none of them had
tried
to breed rats with different levels of fear. The two groups of rats just naturally evolved away from each other in response to different conditions at the two labs. This is what happens in unconscious selective breeding.

The researchers don't know why the rats evolved away from each other. They just know that they did. No one at either of the labs had any kind of agenda other than just to use the rats in normal psych
lab studies, and there wasn't any big difference in the kinds of studies the two labs were doing that could explain why the two descendant groups diverged in personality.

My guess is that the employees at the two labs probably responded differently to aggressive behaviors without realizing it. Say I'm the lady who takes care of the rats at the first lab, and I have a couple of rats who bite—I just get rid of them, because I don't like them. At the other colony you've got the same number of rats who bite, because the rats are all from the same line. But maybe in the second lab you've got a guy with big gloves and he's kind of macho so he
doesn't
get rid of them. Rats who bite get culled out of the gene pool in the first lab, but they live and reproduce in the second lab.