for fight or flight from danger. Research has shown that fear is a universal emotion in mammals and birds. Of course, people have these same physiological responses. A person mugged on a city street and an animal chased by a predator have the same increases in adrenalin, heart rate, and breathing rate. In both animals and people, fear causes fight or flight.
Fear can have very bad effects on the productivity of farm animals. The Australian scientist Paul Hemsworth found that when sows were afraid of people, they had fewer piglets. Fear was measured by determining how quickly a sow would approach a strange person. Each pig was tested by placing it in a small arena with a stranger. Pigs that had been mishandled by workers took longer than other pigs to walk up and touch the strange person. They also had lower weight gains.
Further studies indicated that tender loving care improved both reproductive performance and weight gain. Many large Australian swine farms started a training program to improve employees' attitudes toward pigs. As the workers learned more about pig behavior and became more interested in why pigs act the way they do, productivity increased. Farms where the attitude of the employees improved showed an increase of 6 percent more piglets born per sow. Employees who had a good attitude toward pigs engaged in more positive behaviors, such as petting, and fewer aversive behaviors, such as slapping. Hemsworth also found that pigs that had been slapped regularly had learned to stay away from people and still had sufficient anxiety to cause a chronic elevation of stress hormone and decreased weight gain. They clearly felt threatened when people were around.
Other animals also have the ability to anticipate an unpleasant experience. In one study, dairy cows that had been shocked in a restraining chute had a much higher heart rate when they approached the same restraining chute six months later than cows that had been restrained in the same chute with no shock.
Anatomical and Neurological Measures
The best hard scientific evidence that animals have emotions may come from the study of brain anatomy and neurophysiology. This evidence will help convince the skeptics. I had the opportunity to audit an anatomy class on the human brain at the University of Illinois Medical School. I had dissected many cattle and pig brains, but this was the first time I was going to see what a human brain actually looked like. When the brain was sliced down the middle, I was astounded to learn that the limbic system, which is the part of the brain associated with emotion, looked almost exactly like the limbic system in a pig's brain. At the gross anatomical level, the single major difference between a human brain and a pig's brain is the size of the cortex. The limbic system in both is very similar in size, but the human's is covered by a great massive cortex, like an overgrown cauliflower that engulfs the brain stem. The cortex is the part of the brain that gives people their superior thinking powers. The seat of emotion is buried deep beneath it.
The major difference between the human brain and the brains of other higher mammals, such as dogs, cats, cattle, and horses, is the size of the cortex. Both animal and human brains may get emotional signals from the limbic system, but since people have greater abilities to process information, their expression of emotions is more complex. A sad person may write a beautiful piece of poetry, while a sad dog may whine and scratch on the door when he is left alone. The emotion may be similar, but the expression of the emotion is vastly different.
The chemical messenger systems in the brains of people and higher mammals are the same. Messages between brain cells are transmitted by substances called neurotransmitters. High levels of the neurotransmitter serotonin are associated with calmness and reduced aggression. Prozac makes people feel better because it increases serotonin levels. Some of the other neurotransmitters are norepinephrine, GABA, dopamine, and endorphins. GABA is the brain's own natural tranquilizer, similar chemically to Valium. Endorphins are the brain's own opiates. Drugs such as Naltrexone, which block the action of endorphins, are used in the treatment of heroin overdose and alcohol abuse. Dopamine and norepinephrine have an activating effect. The wild delusions and hallucinations of a schizophrenic are often stopped by drugs that block the action of dopamine.
The best evidence that human and animal emotions are similar is the study of the effect of antidepressant and tranquilizing drugs on animals. Modern veterinarians are treating dogs, cats, and horses with the same drugs that are used to treat anxiety and obsessive-compulsive disorder in humans. A recent seminar by Dr. Karen Overall, from the veterinary school at Pennsylvania State University, sounded like a session at the American Psychiatric Association.
The drug Anafranil, which has actions similar to those of Prozac, is being used to treat obsessive-compulsive behavior in both horses and dogs. A person with this disorder may wash his hands for two hours a day. In dogs, excessive grooming and licking causes open sores. In many cases, a dose of Anafranil will stop the behavior. Judith Rapoport, M.D., an expert on obsessive-compulsive behavior who works at the National Institute of Mental Health, speculates that symptoms in people may come from the older areas of the brain, which we share with animals.
The drug Naltrexone, which blocks endorphins, will stop self-injurious behaviors in both autistic children and horses. Just as a few very severely autistic people will cause self-injury by biting or hitting themselves, high-strung stallions confined to stalls will occasionally engage in chest biting. Dr. Nick Dodman at the Tufts Veterinary School, in Massachusetts, found that Naltrexone will reduce or stop this behavior. He is also successfully using Prozac, beta-blockers, BuSpar (busperone), and Tegratol (carben-mazepine) to control aggression in dogs. Beta-blockers such as Inderal (propranolol) are sometimes used by musicians and actors to reduce anxiety and fear before a performance. Inderal has similar fear-reducing effects in dogs. Dogs are even being treated for hyperactivity with Ritalin (methylphenidate). Both hyperactive dogs and hyperactive children become calmer on the drug.
I would speculate that the most basic emotions in people and animals have similar neurological mechanisms and that the difference between human and animal emotion is the complexity of emotional expression. Emotions help animals survive in the wild, because they provide intense motivation to flee from a predator or protect newborn offspring. Instinct refers to fixed behavior patterns in animals, such as mating rituals, but they are fueled by emotion. It is likely that an animal is motivated by fear to find a secluded place to nest that is safe from predators, but fear would not be the primary emotion in a hungry animal. Hunger and fear are both intense motivators.
Like a prey-species animal, many people with autism experience fear as the primary emotion. When I was charting my life in the visual symbol world, I did not know that most people are not driven by constant fear. Fear fueled my fixations, and my life revolved around trying to reduce it. I delved deeper into my visual symbols because I thought I could make the fear go away if I could gain an understanding of the significance of my life. It got to the point that everything I did assumed symbolic significance on my visual map. I thought that an intellectual understanding of life's great philosophical questions would turn off the anxiety. My emotions were primal and simple, but the symbolism of my visual symbol world was extremely complex.
I replaced emotional complexity with visual and intellectual complexity. I questioned everything and looked to logic, science, and intellect for answers. As a visual thinker, I could understand the world only in that way. I kept striving to turn off the fear until I discovered the powers of biochemistry.
Both people and animals have temperament traits that are genetic and inborn. A fearful animal and a fearful autistic person are both stressed and upset by new routines and strange things. Training and taming can mask flighty temperament traits, but they are still there under the surface, waiting to explode. A bull from a nervous genetic line may be placid and calm on his familiar ranch but go berserk when he is confronted with new surroundings and new people. Likewise, some autistic people are very calm when they adhere to familiar routines, but an outburst of temper or aggression can occur if something unexpected happens.
Dr. Jerome Kagan and his associates at Harvard University have found that inborn temperament traits first start to show up in children at age two. Their categories of inhibited and uninhibited children are very similar to those of calm and excitable cattle or horses. These basic traits become apparent during very early childhood. Shy or inhibited children are wary of others, and they tend to be cautious and avoid strangers. Uninhibited children are more outgoing and social and less afraid of new experiences. Learning and social influences mask and override most of these differences, but children at the extremes of the spectrum retain the differences.
In Kagan's study, the extremely shy, inhibited children had greater physiological reactivity. When they were exposed to new tasks and strange people, their heart rate increased. They also had higher cortisol levels than uninhibited children. Kagan speculates that shy children have a more sensitive sympathetic nervous system, which reacts quickly and intensely, so that novel situations are more likely to cause them to panic. Possibly they are like
