Ecology: the biology of interaction. 6.18. (supplement) Cultural inheritance as a mechanism of transmitting acquired traits

Ukrainian language (latest version) / Russian language (update discontinued)

6.17. (supplement) Unique ecological features of humans D. Shabanov, M. Kravchenko. Ecology: the biology of interaction Chapter 6. Human ecology and nature conservation

D. Shabanov, M. Kravchenko. Ecology: The Biology of Interaction Chapter 6. Human Ecology and Nature Conservation

6.19. (supplement) The mechanism of human behavior as a result of the evolution of the behavior mechanism of other animals

6.18. (supplement) Cultural inheritance as a mechanism of transmitting acquired traits Children of the bent grow hunchbacked V. A. Shenderovich Every species evolves to fit a particular way of life in the characteristic conditions of its habitat. Adaptations acquired during evolution may be linked both to changes in the body (the emergence of new organs or new functions) and to changes in behavior (the emergence of new reactions or modes of action). Differences in the lifestyle of many spiders are related to how they use their web, not to the structure of their silk glands. Corvids are highly adaptable not so much because of their morphological or physiological features, but thanks to behavioral flexibility. Naturally, a necessary condition for behavioral adaptation is the presence of a “base”—the brain, sense organs, and organs that execute the brain’s “commands.” To understand what follows, one must turn to an old problem of evolutionary biology. In our understanding, the idea of inheritance of acquired characteristics became associated with the name J. B. Lamarck, although Lamarck merely echoed the views prevailing in his time on this issue. Changes that occur in an organism during its life are transmitted to its offspring—thus, the correspondence of an organism to its environment develops. That acquired traits are not inherited was proclaimed by A. Weismann. Later, the “Darwinian” concepts of evolution were linked with Weismann’s views on the non‑inheritance of acquired traits. An important exception that deserves closer examination was Soviet biology during the dominance of T. D. Lysenko. With the final victory of Soviet power in the USSR, a radical restructuring of animal husbandry and plant cultivation was required—a shift from individual to collective farming. New animal breeds and plant varieties were needed. Within the framework of the planned economy, scientific institutes and breeding stations were to fulfill the party’s and government’s tasks within a short, predetermined period. By that time, the USSR had a leading school of genetics and breeding, headed by N. I. Vavilov. Considering that predispositions, not qualities, are inherited, specialists had to demand sufficient time for their work. Even if a cow named Manka produces a lot of milk, her daughters may not inherit this trait; to determine how their hereditary endowments will manifest, they must be raised. Moreover, it turns out that milk yield in cows depends on the sire, their father, who is not even milked… Thus, breeding is a long and complex undertaking. The essence of life at that time was clear: Engels established that it consists in metabolism. The assertion of the existence of “genes,” which are neither destroyed nor created during metabolism, was inevitably perceived as idealistic. It could be understood as the hereditary program (“idea”) being primary, and its implementation during metabolism (“matter”) being secondary. A distinct social mandate emerged for biologists who, using dialectical materialism, would manage the exchange of heredity and alter organismal properties in the desired direction. The most successful in promising to fulfill this mandate was T. D. Lysenko, a non‑established protégé of N. I. Vavilov. Lysenko claimed that heredity could be “shaken loose” and that, in a short time, the necessary acquired traits could be inherited for the party and the government. Naturally, the state leadership supported Lysenko and his followers, and when geneticists began to explain why Lysenko’s approach would fail, “anti‑Soviet agitation” was brutally suppressed. Vavilov died in prison of starvation shortly before Stalin agreed to Churchill’s demand to transfer him to the Red Cross; many lower‑rank biologists were erased into the camp dust or intimidated. Why does this textbook turn to that tragic history? For further reasoning it is crucial that the inheritance of acquired traits would significantly accelerate evolution. An adaptation to certain environmental requirements may be a structure or a specific behavioral reaction. On what basis is behavior formed? For most animals, on the same basis as other traits. During development, which proceeds under genetic control, a particular structure forms in the nervous system that ensures the required behavior. A bee is born ready to communicate the location of food by dancing, and a raccoon is innately inclined to wash food in water. However, there is a second way of acquiring adaptive behavioral traits, called cultural inheritance, i.e., transmission of a trait through learning. A well‑described example of cultural inheritance is found in Japanese macaques on Koshima Island. In 1953 observers recorded a case in which a young female named Imo dropped a sand‑coated sweet potato (tuber) into water and ate it clean. She linked these events and began dipping other sweet potatoes in water. Some of her conspecifics (except those older than her) “monkey‑imitated” and adopted the habit. After a while the same female tried throwing rice into water, thereby separating it from sand grains. Within one generation these traits spread among all monkeys of that population! Undoubtedly, the spread of this trait through biological inheritance (as observed in raccoons) would have required an extremely long period. In England, several decades ago, milk bottles with tin caps were common. Milk vendors would circle customers’ homes in the morning and leave bottles at their doors. Some tits learned to peck off the caps of milk bottles and eat the cream. Soon such cases became systematic, and dairies had to switch to sturdier packaging. The speed of spread of the new trait unequivocally proves that it was inherited culturally, just as songs are culturally inherited in singing passerine birds, certain hunting techniques in predatory mammals, and a number of other animal traits. Although cultural inheritance occurs in many animal species, humans are the only species for which it has become primary. Deprived of many specific adaptations, humans evolved thanks to their capacity for flexible behavior that adjusts to diverse environmental conditions. As the mechanism of cultural inheritance (occurring on a biological foundation) became more refined, an individual’s adaptability was increasingly determined not by what was biologically inherited, but by what was learned. Note: biological inheritance in the typical case proceeds without inheritance of acquired traits, whereas social, cultural inheritance does involve them! Approximately 40–50 thousand years ago, directed biological evolution of humans slowed markedly, continuing only with the elimination of individuals markedly deviating from the biological norm. Humans began to adapt to the environment culturally. That is why humans are a biosocial being—they possess two natures: biological and social (culturally inherited). To denote a unit of cultural transmission (by analogy with the term “gene”), the English evolutionary biologist Richard Dawkins proposed the word “meme.” A meme is any culturally transmitted unit: a method of sprinkling oysters with lemon juice, a fashionable catchphrase, the habit of terminating Windows with Alt+F4 rather than Shut Down, etc. (including the skill of pecking off milk‑bottle caps). The development of humanity can be attempted to be described “in the language” of memes. However, the systematic application of Dawkins’ approach encountered difficulties. To understand these difficulties, one must consider that element‑by‑element description of complex systems composed of many interacting parts proves ineffective. Thus, despite the productivity of the concept of the “gene,” describing the heredity of a somewhat complex organism as the sum of its genes is impossible. Already in the 1930s geneticists concluded that it is not individual genes but the whole genotype that determines an organism’s properties (which does not refute the existence of some simply coded traits). The reason is gene interaction. Apparently, cultural components also interact closely, and “decomposing” culture into memes is not feasible. This does not mean that the meme concept is useless. For example, it can be used to describe the phenomenon of cultural exchange between two related species: Homo sapiens and Neanderthals. From the time these species coexisted, material‑culture artifacts have survived. In describing them, individual memes can be identified and then their transmission from species to species recorded. Some memes registered in Neanderthals persist to this day. For instance, a Neanderthal hunter buried 60 000 years ago in the Shandidar cave in Iran lay on a layer of pine branches and was covered with flowers. Wreaths of flowers on pine branches that we bring to funerals have a long prehistory… The emerging space of cultural inheritance has its own features. It developed as a means of adapting to a changing environment. Unfortunately, the most widespread memes are not those with the greatest adaptive value, but those that are transmitted most easily because of their primitiveness or stickiness. This is linked to the sad phenomena of mass culture and crowd feralness. On the other hand, we can influence our cultural evolution (for example, through proper organization of education) far more than our biological evolution. “Neurophysiologist James W. Prescott conducted a striking cross‑cultural statistical analysis of 400 pre‑industrial societies and found that where children receive ample physical affection, people tend to reject violence. Even societies that do not habitually caress children produce adults less inclined to violence, provided adolescent sexuality is not suppressed. Prescott argues that cultures prone to violence consist of individuals deprived of bodily pleasures during two critical life periods: childhood or adolescence. Where physical affection is encouraged, there is no propensity toward theft, organized religion, or ostentatious luxury; where physical punishments are applied to children, customs include slavery, frequent killings, torture, and maiming of enemies; in such societies women are regarded as inferior beings and belief in one or several supernatural entities intervening in daily life prevails. We do not understand human behavior well enough to state definitively the mechanisms underlying these relations, yet we can hypothesize about them. Prescott writes: “The probability that a society encouraging affection toward children and tolerating premarital sexual relations will be prone to physical violence is two percent. The chance that this correlation is random is 1 in 125 000. I know of no other parameters with such high predictive power.” Children greatly need physical affection; adolescents are powerfully driven by sexuality. If they receive what they desire in youth, society produces adults less inclined to aggression, territoriality, ritual, and social hierarchy (although as they grow, children may acquire considerable reptilian‑type behavior). If Prescott is right, in the nuclear‑age and with effective contraceptives, child abuse and suppression of sexuality constitute crimes against humanity. Meanwhile each of us can make an undeniable personal contribution to the future of the world by gently embracing our children” (Carl Sagan, 2005). Additional materials: August session: retirement age Learning model: Mechanisms ensuring adaptive behavior Column: Gift of Isora, or a game of beads Column: Coffee and co‑knowledge of the noosphere 6.17. (supplement) Unique ecological features of humans

D. Shabanov, M. Kravchenko. Ecology: the biology of interaction Chapter 6. Human ecology and nature conservation

6.19. (supplement) The mechanism of human behavior as a result of the evolution of the behavior mechanism of other animals

6.19. (addendum) The Mechanism of Human Behavior as a Result of the Evolution of the Behavior Mechanism of Other Animals