Why do you really need a brain

In continuation of the previous topic " How the brain actually works ." On writing this post, I was prompted, on the one hand, by the wonderful book “Grooming, Gossip, and the Evolution of Language” by Robin Dunbar (Robin Dunbar), and on the other, by another piece of “useful” and “smart” advice on GTD and other blogs .

For the seed - a small logical task. A set of cards is given; on each of them a letter is written on one side and a number on the other.
On the table are four cards: "A", "D", "5" and "6". You are told: if on the card (from among those lying on the table) there is a vowel on one side, then on the back there is an even digit. Which of the cards is enough to turn over to unequivocally confirm or refute this statement?

Think a little, write down the answer on a piece of paper and welcome under kat.
')


Now solve this problem: you enter the bar and you see four visitors who are drinking something. You know for sure that the first is 14 years old, the second is 25, the third is drinking whiskey, and the fourth is coke. Which of them need to be checked to make sure that the alcohol was not sold to minors?

Well, everything is simple: the first and third. The second is an adult and can drink what he wants, and the fourth drinks cola, you can drink it at any age.

Now go back to your piece of paper and compare the answer with the numbers written there. The first task is completely equivalent to the second - you need to turn the first and third card (on the second - a consonant, about which nothing is said, but on the fourth - and so is an even digit).

Meanwhile, about 75% of respondents do not cope with the first problem, although they solve the second one very well. The requirements for the logical thinking proper imposed by both tasks are absolutely identical. What is the difference?

The difference is that the second task is formulated in social terms. And the human brain is then precisely needed to solve social problems, and not at all for some abstract thinking.

Social brain

The belief that the brain developed in humans during evolution in order to process factual information, analyze incoming information and make the right decisions (that is, think better, in short) was generally accepted in the scientific community almost from the time of Darwin , and in the unscientific remains so to this day. However, in the 1990s, a group of evolutionary scientists advanced an alternative statement known as “social brain hypothesis”: the brain (or rather, the neocortex, the new cerebral cortex) developed during the course of evolution in order for primates to maintain more social connections. and, as a result, a larger group size.

The starting point of the social brain hypothesis was the question of evolutionary factors favoring an increase in the size of the neocortex. The brain (see previous post) is an extremely energy-intensive organ, and therefore it cannot develop “by itself” - the benefits it provides should also be extremely large. However, traditional theories cannot provide a satisfactory explanation of exactly what benefits primates receive from having a large neocortex (for more, see Robin Dunbar, " The Social Brain Hypothesis ").

In 1992, Dunbar brought together in one diagram the relative size of the neocortex for different primates and the typical size of the group for this species. And I got this picture:



Quite unexpectedly solitaire converged. There is a clear direct relationship. If the schedule is extrapolated to a person, the size of the group will be ~ 150 (the so-called Dunbar number ), which still corresponds to the size of primitive communities.

Of course, the existence of a good correlation in itself does not prove anything, but it is not yet possible to find some alternative explanations for the size of the neocortex in primates, and the theory of the social brain is also confirmed by some other (including falsifiable) conclusions (see below ).

Let us assume for now that the hypothesis is correct. Why do primates need a developed neocortex to maintain the integrity of society, when other social animals easily do without it? Is there any difference between the social thinking of primates (and humans) and other animals?

Theory of mind

It turns out there is. In the English-language literature, the phenomenon of human social thinking is called the Theory of Mind (ToM), in the Russian-speaking - the mental model (alternative options are the theory of intentions, the theory of consciousness). In short, man and primates interact socially with the full understanding that another individual is also a person, with his own intentions and ideas about the world.

The development of social abilities in children is well studied. The first most important prerequisite for the development of ToM is the understanding of attention: a child aged 7-9 months is able to understand that the attention of an adult is directed to some external object. The second most important prerequisite is the understanding of the difference between the random and intentional actions of other people - this ability develops approximately at the age of 2-3 years. Primates also possess these two abilities.

A critical turning point in the development of a mental model occurs at the age of 3-4 years. At this age, the child begins to understand that the ideas of others about the world around may differ from his own. To test this ability is usually used so-called. false belief test; it is usually performed in the form of an Ann-Sally test.

The subject is represented by two characters - Ann and Sally (in the classic series of experiments of Wimmer and Perner, dolls play their role). Sally has a basket, Ann has a box. Sally puts some item in the basket (Wimmer and Perner used a glass ball) and leaves the room. Then Ann takes the item from the basket and puts it in his box. After which Sally returns and the subject is asked the question: where will Sally search for the item?

Children under the age of four are unable to cope with this test and always point to the box. They do not understand that Sally did not see how the subject was shifted; the idea that someone can share a deliberately wrong belief simply does not occur to the child.

What is even more interesting, the ability to realize the fact that the representations of another person may be deliberately false, apparently, laid genetically. Children with autism (as well as adults with severe disorders) are unable to pass the Ann-Sally test. Moreover, the inability to fully develop ToM does not correlate in any way with the level of IQ - children with Down syndrome pass this test perfectly. Autists with high IQ are able, after all, to just memorize the right answers to typical social situations (including the Ann-Sally test), but they are not able to understand the meaning of these answers.

We now return to the primates. Can they pass the false-belief test? The task of "Ann - Sally" was repeatedly tried to reformulate so that it was understandable and animal. Research results show that our closest relatives — chimpanzees — are far from ideal, but they are still able to pass this test.

So, primates and man, unlike other social animals, are able to understand that another individual is also a person with his own personal aspirations and beliefs. It is curious that this fact echoes Dawkins' assumption about the meaning of consciousness (for more details, see one of my old posts ): consciousness arises at the moment when the brain begins to incorporate into the models of the world it has created itself as an integral part - and the need to do so arises for in order to predict the behavior of other individuals (and how would I do in his place?). Jordania even added to the Cartesian "cogito ergo sum" with the statement "interrogo ergo cogito" - "I communicate, therefore I think."

The primate society is thus held together through the CONSCIOUS cooperation of its members; each individual maintains his own social network and keeps in memory information about each other individual and his attitude towards him. To maintain these relations, primates allocate a huge (up to 20%) share of their time (more - only for a search for food). Now you understand why Vkontaktik and ICQ are so important for a person?

The scientific literature contains examples of completely amazing social maneuvers among primates. I will cite one of them, from the book The Politics of Chimpanzee, by Frans de Waal.

The young male Liuit dismissed the old male Jeroen from the top of the hierarchy. Jeroen, who has long been a dominant male, was in second place on the social ladder. After some time, another young male, Nikki, moved Jeroen to third place, thereby depriving all privileges (above all, access to females). Then Jeroen made an alliance with Nikki, and Nikki, with the support of Jeroen, was able to defeat Luit and take first place. Jeroen thus returned to the second.

The new “tsar” Nikki, of course, did not like the dual power, and he, of course, tried to limit the privileges of Jeroen. The same waited when Nikki once again get involved in a fight with Lyuit, and defiantly refused to support him. Nikki, of course, lost this fight - and, in order not to lose the war, he was forced to renew the alliance with Jeroen and return his privileges.

Machiavelli would probably have marveled at Jeroen’s political talents. It seems that only the most biased skeptic can say that the situation described is a chain of accidents or instinctive behavior, and not conscious manipulation by Jeroen.

That's it for this, to store its social network, to manipulate others, to search for loopholes in the social structure (and to identify such cheaters), a developed brain is needed for primates and humans. The ability to solve differential equations and write Mona Lisa is a pleasant, but still a side effect of having a highly developed brain.

Naturally, the larger the brain size - the one, on the one hand, the more social connections the individual can keep (and the larger the group lives on) and, on the other hand, the more effective social strategies he is able to implement.

As for the first, then, apparently, the need to maintain a larger group size was the factor that eventually led to the emergence of man. A few million years ago, our remote ancestors were driven out of tropical forests for environmental reasons and were forced to move closer to the outskirts and move a lot of time in open areas to which they were very poorly adapted - a person has nothing to oppose to large savannah predators except for actions by an organized group. More group - more chances to survive. A very strong selection factor has arisen, favoring individuals with a large brain.

As for the second — more effective social strategies for owners of the large brain — Pavlovsky and Dunbar put forward an original hypothesis, which states that as the size of the neocortex increases, an individual has more opportunities for social cheating, and in particular, more opportunities for mating. In primate social systems, high-ranking males usually simply do not allow low-ranking to females, and there is little chance of leaving offspring, so low-ranking males have very little. But a developed brain allows you to cheat and look for ways to circumvent the prohibitions - therefore, with increasing brain size, an increase in the number of offspring from low-ranking males should be observed. And this hypothesis was confirmed - in primates with large neocortex, low-ranking males leave more offspring.

Speech as a means of social communication

To maintain the social network, primates use physical contacts — grooming (including sexual ones, for example, in bonobo chimpanzees ). However, as the size of the group grows, grooming becomes too expensive - especially since the ancient human ancestors found themselves in a difficult environmental situation and were forced to travel a lot on the savannah, which hardly contributed to the appearance of additional free time.

Dunbar believes (and proves on the basis of correlations between brain size, group size and time needed for grooming) that as a result, human ancestors were forced to switch to another type of social intercourse - voice. For several million years, vocal intercourse evolved until it finally turned into a full-fledged speech (the evolution of vocal intercourse at the moment is one of the hottest topics in anthropology and I will not dwell on it in detail). Voice communication allows you to get rid of a number of disadvantages of grooming - it frees your hands, allows you to communicate with several individuals at once, and remotely. Dunbar conducted a series of studies, during which he found out that the optimal size of an informally communicating group is 4 people, large groups begin to disintegrate into smaller ones. So speech as a means of social communication is about 3 times more effective than grooming (3 interlocutors instead of one). Strikingly, the size of a person’s social group (150) is about 3 times the maximum size of a social group in primates (50 individuals in chimpanzees).

Yes, speech, too, like the brain, is needed primarily for social interaction. Studies show that the discussion of social themes takes about 65% of the time in the structure of human communication (meaning, of course, informal communication), and this figure is the same for both male and female companies. Approximately 2/3 of the conversations are devoted exclusively to who, where, when and with whom. The only significant difference in male and female conversations is the ratio of personal and other people's social experience - women talk much more about others and men talk about themselves. At the same time, however, it should be noted that in groups of mixed sex composition the structure of a conversation seriously changes - about 15-20% of the time men talk about art, politics, religion, education and other important things, although in a purely male company the share of conversations on abstract topics does not exceed 5%. Simply put, men start advertising themselves this way. For more information about the structure of human communication, see Gossip in Evolutionary Perspective .

At the same time, a modern person devotes approximately the same amount of time to communication (including voice), as our closest relatives of chimpanzees - to the grooming: about 20%.

Social man

So, in short, the conclusions: a person needs the brain to maintain social ties and manipulate other people; and speech is a means for social interactions. The ability to lie, cheat, cheat, as well as be friends (with someone and against someone), enter into alliances and act together - this is exactly what distinguishes a person (and to some extent primates) from animals; and, quite possibly, self-awareness also appeared in order to better manipulate other people.

Therefore, when I read the pretentious reasoning of another moral philosopher about the lowland of human nature and that a person is worse than a beast, I, frankly, become ridiculous. Our ancient ancestors, by and large, therefore became people because they learned to deceive (see false belief test) and intrigue. I do not like? Look for another globe.

Just as it makes me laugh, when I see more talk about how “meaningless” people spend time sticking to contact and chatting with girlfriends / friends. The brain is then human and given to communicate. I do not like? Look for another globe.

And, in conclusion, I would like to note the following point: although thanks to a developed brain, a person is capable of any meanness and on top of social ladders are often mediocre and ignorant, but still, quite paradoxically, but human society in comparison with societies of other animals is the most humane and least based on coercion. Evolutionary pressure, pushing a person towards the formation of larger social groups, brought to the fore the ability of a person not only to deceive and cheat, but also to be able to negotiate and cooperate with others, resulting in human civilization. Remember this too.

PS And, nevertheless, it’s a pity that the book of Dunbar didn’t come across to me 8-10 years ago - the concept of facebook after reading it emerges by itself.