Things donors know: how evolution can create emotions

Those who expose themselves to questions about science receive quite a few questions about the theory of evolution. The surfer "Basad" challenges the idea and challenges Darwin with a series of questions, one of which we will discuss this time. How were the feelings created? How can evolution create emotions?

You didn't just ask how evolution can create emotions and not how it can create hearing or a balance mechanism. The reason for reluctance to engage in this branch of evolution is emotional and religious. Emotions are the element that we identify with being human, it is hard to accept that love or friendship are qualities shaped according to the laws of natural selection just like the wings of a fly or the spines of a saber. Evolution of emotions means that we stand on the same developmental continuum with other creatures and not as the "crown of creation". The philosopher Descartes ("I think means I exist") saw animals as a kind of soulless machines and the absence of language served as proof for him that "if there were machines in the world with the limbs and face of a monkey or of some other animal, we would have no means of recognizing that their nature is not similar in all To the nature of these animals" Descartes attributed the sensitive human soul only to man.

Shlomo Maimon, a Jewish philosopher who was influenced by Descartes tells about a trip he took with his friends "and here in the middle of the road lay a goat. I gave the goat a few blows with the stick and my friends accused me of cruelty. I answered: 'What cruelty? Do you think the goat feels pain if I hit it? You are very wrong. According to Descartes the goat is merely a machine. My friends said: 'Don't you hear her scream when you hit her?' To which I replied: 'Of course she is shouting. If I hit the drum, the drum also makes a sound." It is almost unnecessary to point out that while Descartes' mathematical and philosophical achievements are important even today, as a biologist he is an ardent failure. There is no mental difference between us and the animals that can deprive them of feelings. In fact, as information accumulates about the behavior of mammals and birds, it becomes clear that their emotional world is quite similar to ours. For example, elephants "bury" their dead by covering them with branches and even exhibit behavior that is difficult not to interpret as mourning. Not many people know this (and Shlomo Maimon certainly didn't think so when he hit the poor animal) but when the kebab was still a lamb he was able to recognize the faces of 10 people and 50 other sheep. When the lamb is isolated from the herd, it shows stress and distress that can be alleviated by showing pictures of its former friends and deep friendships are formed within the herds of sheep and cattle. It seems that there is almost no human emotion that does not have a counterpart in quadrupeds, including behaviors of supporting the weak and the sick that we attribute to the most noble and "human" emotions, for example, groups of monkeys adjust the speed of their progress to the rhythm of the sick and the weakest and a bat is ready to act as a babysitter for its friend when it goes out to look for food . However, it is difficult for facts to deal with faith, and thus, more than 200 years before Darwin, Descartes anchored his principled opposition to attributing a soul to animals also on moral grounds: "There is nothing that keeps the weak-minded from the straight path of virtue than the idea that the nature of the animal soul is like the nature of our own soul." It is interesting that the Sages believed that knowing the similarity between us and animals may improve our behavior "Rabbi Yochanan said: If the Torah had not been given we would have learned chastity from a cat and greed from an ant and lewdness from a pigeon through the earth from a rooster...". Animal cruelty laws in the Torah recognize the ability of a bird to feel sorry for its chicks and of a working animal to enjoy the Shabbat rest. It seems that Moses' occupation as a shepherd made him a better zoologist than Descartes.

Where is the emotion anyway?

In one word: in the brain. Physiologist Paul MacLean created an evolutionary model of the brain according to which our skull contains no less than 3 brains that represent different evolutionary stages of development and perform different tasks. The earliest part of the brain, which has much in common with "primitive" life forms such as reptiles and amphibians, is also the deepest and includes the brainstem and brain (cerebellum). The "reptilian" brain is responsible for simple responses to defined stimuli: appetite following the smell of food or running away when encountering threat. The actions directed by this part of his mind are mechanical, repetitive and not influenced by experience. The middle part of the brain is the "limbic" brain or the "primitive mammal" is responsible for emotions such as fear, anger, joy, and the memory of feelings and sensations. The brain cortex (neocortex) or the new mammalian brain is the latest part of the brain from an evolutionary point of view responsible for abstract thinking and is especially developed in our monkey family members and in us, humans. In humans, the cerebral cortex is particularly developed and occupies about two-thirds of the brain's volume. A mouse without a cerebral cortex will function almost normally, but a person whose cerebral cortex has stopped functioning is a plant. But the cerebral cortex or "thinking brain" never works alone. The limbic, emotional part is essential for thinking and is responsible for determining the "order of priorities" of the brain and the distribution of attention. The knowledge acquired since McLean formulated his three-brain model requires changes in the theory, and it is possible to observe the appearance of brain functions in increasing degrees of complexity in the evolutionary sequence of vertebrates. Emotions, unlike bones or teeth, do not leave evidence in fossils: even if we knew everything about the dinosaur's body structure, diet and habits, we would not know if it felt fear or jealousy. And yet it is possible to know something about the development of emotions by looking at different animals living with us today. If indeed our emotions are a product of natural selection, then we would expect to find them in our relatives and less in those who sit on a distant branch from us in the tree of evolution.

To determine the date of birth of the emotions we must find the most primitive group in which an emotion appears. In recent years, observations have shown that Paul McLean did reptilians an injustice by attributing emotionless automaticity to their minds. Thus, for example, turtles clearly prefer a yard rich in stimuli to a boring yard that offers the same food. Tortoises also tend to show signs of stress after handling them: they tend to approach a heat source and their heart rate increases for a long time after the handler has taken them into his arms. Signs of emotion-directed behavior were also observed in lizards and other reptiles, but not in the reptiles' evolutionary ancestors: the amphibians and fish. These studies extend the appearance of the first emotions to the development of reptiles from amphibians about 300 million years ago. However, the emotional world of mammals is more complex than that of other vertebrates. For example, frustration is a distinct mammalian emotion: a pigeon whose nest is repeatedly removed from the balcony returns and builds it in the same place without signs of emotional distress.

 What is good for?

Historical tracking still does not answer the heart of the question. If emotion is a trait shaped by evolution, it is necessary to check, as in any evolutionary development, how emotion helps in natural selection: why are the chances of the sensitive to produce offspring greater than the chances of their "automatic" competitors.

Those who deal with this question are scientists who try to understand the nervous system and its products (such as emotion) in terms taken from the world of computer science. The brain is an information processing mechanism and as such it can handle the input that reaches it from the senses at several levels. The reflexes are the equivalent of a simple function, a certain input produces a known output: the smell of food will trigger an appetite and the sight or sound of a predator will trigger an escape response. This is enough to enable survival, but in a system that is nothing more than a collection of stimulus-response mechanisms, there is a danger of a collision between two functions: what to do if an enemy appears in the field of vision along with the tempting smell of food? There is an advantage to the software that will arrange the various functions, set their priorities and turn off the ones that are not necessary for the situation. Emotion is, according to those scientists, a kind of super-program that activates and deactivates various programs. Take for example a person or an animal walking alone at night in a dark forest. The stimuli flow from all the senses but there is no point in referring to all of them but only to those that improve the chances of ending the journey outside the belly of a predator.

Fear is a kind of "super-program" that makes it possible to ignore stimuli that might arouse appetite, sexual desire or curiosity and to increase sensitivity to sounds that might hint at suspicious movement in the thicket. From the memory, previous events of meeting with hostile elements are extracted to which the new stimuli are compared: other memories are not necessary and there is no point in browsing through them. Determining this order of priorities allows for the distribution of resources: weakening the blood flow to the digestive and reproductive organs and increasing the blood flow to the muscles. When a new creature appears, the reaction will be chosen from a limited range of options: escape, attack or hide without wasting precious time. A cowardly creature has, therefore, a better chance of producing similar offspring than an animal that behaves like a Descartes automaton.

Fear is perhaps the easiest emotion to understand its evolutionary meaning, but other and more "refined" emotions serve a similar purpose. Even the pursuit of honor, love, or jealousy has its roots in the world from which our ancestors evolved. The repeated encounter with similar situations over many generations led to open information processing mechanisms that have a survival advantage. Thus, for example, with animals in a herd of high status, it is those who get to produce offspring: a monkey who adapts the modest philosophy of Diogenes in a barrel (the one who renounced the lack of honor and status) will perhaps gain peace of mind but not the favor of the females. Thus there is an advantage to the feeling of competition and the striving for status that will organize our decision-making processes in the group.

There are emotions that seem, at first glance, to be worthless for survival such as grief over imminent death (an emotion shared by us and some other mammals), enjoyment of play, wonder, guilt, etc. - moods that will not help us feed our children or escape from a predatory tiger. But, in the long run, such feelings enable more effective learning, adapting to changes in the physical or social environment and adjusting our priorities to what will promote the group's situation and our position within it. Evolution does not mean "survival of the fittest" but "survival of the fittest" and emotion is not an obstacle but a condition for success in the war of existence.

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More of the topic in Hayadan:

• The areas of joy and sadness - the emotions "take sides" part two of the chapter 'The Unity of Contrasts' in the book Behind the Scenes of the Brain Show'
• The machine searches for meaning - the following technologies according to Accenture
• Human evolution is still happening and may even be accelerating
• Weizmann Institute of Science scientists discovered: what is the connection between financial loss, emotions and evolution