Tag Archives: evolution

Exaggerating vs hiding emotions

In some cultures, it was a matter of honour not to show emotions. Native American warriors famously had stony visages. Victorian aristocracy prided themselves in a stiff upper lip and unflappable manner. Winston Churchill describes in his memoirs how the boarding school culture, enforced by physical violence, was to show no fear. In other cultures, emotions are exaggerated. Teenagers in North America from 1990 to the present are usually portrayed as drama queens, as are arts people. Everything is either fabulous or horrible to them, no so-so experiences. I have witnessed the correctness of this portrayal in the case of teenagers. Jane Austen’s “Northanger Abbey” depicts Victorian teenagers as exaggerating their emotions similarly to their modern-day counterparts.

In the attention economy, exaggerating emotions is profitable to get and keep viewers. Traditional and social media portray situations as more extreme than these really are in order to attract eyeballs and clicks. Teenagers may have a similar motivation – to get noticed by their peers. Providing drama is an effective way. The notice of others may help attract sex partners or a circle of followers. People notice the strong emotions of others for evolutionary reasons, because radical action has a higher probability of following than after neutral communication. Radical action by others requires a quick accurate response to keep one’s health and wealth or take advantage of the radical actor.

A child with an injury or illness may pretend to suffer more than actually to get more care and resources from parents, especially compared to siblings. This is similar to the begging competition among bird chicks.

Exaggerating both praise and emotional punishment motivates others to do one’s bidding. Incentives are created by the difference in the consequences of different actions, so exaggerating this difference strengthens incentives, unless others see through the pretending. Teenagers may exaggerate their outward happiness and anger at what the parents do, in order to force the parents to comply with the teenager’s wishes.

On the other hand, in a zero-sum game, providing information to the other player cannot increase one’s own payoff and usually reduces it. Emotions are information about the preferences and plans of the one who shows these. In an antagonistic situation, such as negotiations or war between competing tribes, a poker face is an information security measure.

In short, creating drama is an emotional blackmail method targeting those with aligned interests. An emotionless front hides both weaknesses and strengths from those with opposed interests, so they cannot target the weakness or prepare for the precise strength.

Whether teenagers display or hide emotion is thus informative about whether they believe the surrounding people to be friends or enemies. A testable prediction is that bullied children suppress emotion and pretend not to care about anything, especially compared to a brain scan showing they actually care and especially when they are primed to recall the bullies. Another testable prediction is that popular or spoiled children exaggerate their emotions, especially around familiar people and when they believe a reward or punishment is imminent.

Learning and evolution switch the sign of autocorrelations

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Animals are more successful if they learn or evolve to predict locations of food, mates and predators. Prediction of anything relies on correlations over time in the environment. These correlations may be positive or negative. Learning is more difficult if the sign of the correlation switches over time, which occurs in nature due to resource depletion, learning and evolution.

If a herbivore eats a tasty patch of plants or a predator a nest full of eggs, then the next day that food is not there (negative correlation), but the next year at the same time it is probably there again (positive correlation) because the plants regrow from roots or seeds, and if the prey found the nesting spot attractive one year, then other members of the prey species will likely prefer it the next year as well. However, over many generations, if the plants in that location get eaten before dispersing seeds or the young in that nest before breeding, then the prey will either learn or evolve to avoid that location, or go extinct. This makes the autocorrelation negative again on sufficiently long timescales.

Positive correlation is the easiest to learn – just keep doing the same thing and achieve the same successful outcome. Negative correlation is harder, because the absence of success at one time predicts success from the same action at another time, and vice versa. Learning a changing correlation requires a multi-parameter mental model of the superimposed different-frequency oscillations of resource abundance.

There is a tradeoff between exploiting known short-period correlations and experimenting to learn longer-period correlations. There may always be a longer pattern to discover, but finite lifetimes make learning very low-frequency events not worthwhile.

Why princesses and princes are described as attractive

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The bards and scribes who recorded events for posterity received their income essentially in the form of tips from the rulers and the rich, so had an incentive to flatter, describing their patrons as more attractive, virtuous, brave, etc than they really were.

In addition to the exaggeration of their actual attractiveness in reports that have reached us, the children of the wealthy probably really were more beautiful than the poor. Richer youth were better fed and cared for, thus had fewer developmental abnormalities (e.g. bent legs from calcium deficiency) and diseases. The poor were malnourished, lived in dirty conditions and were subject to violence, therefore were more likely stunted, stank and had skin diseases, missing teeth and scars. The latter two distinctions in looks have to a lesser extent lasted to the present day, for the same reason.

Attractiveness consists of the visual, audible and olfactory signals of a fit mate (healthy, fertile conspecific), because organisms evolved to consider fit mates attractive. In times when most people were malnourished and diseased, a well fed and healthy rich person would have been much fitter than most, thus a preferred sexual partner for others.

On the other hand, conditional on surviving to adulthood, the poor likely had better immune-related genes, because they were under stronger selection pressure. Poorer people also experienced more infections, thus acquired stronger immunity to more diseases if they survived. Then conditional on equal looks, a person from a poorer background would have been a fitter mate. Also, the ruling class intermarried to keep wealth in the family, so were inbred (hereditary diseases among European royalty are an example consequence). For these two reasons, it is not surprising that the rulers and the rich found some poor people sexually attractive, specifically the outwardly healthiest-appearing among those who reached maturity.

Avoiding an animal on the road

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When a bike or car heads towards a squirrel, the squirrel first dodges to one side and then runs away in the other direction. Birds fly directly away from the oncoming vehicle, so stay in front of the vehicle for a few seconds. These behaviours are presumably evolutionary adaptations to avoid predators. For example, the squirrel’s dodge probably misleads a predator to alter course in the direction of the dodge. The larger predator then has more difficulty than a small agile squirrel in switching direction to the opposite side of the dodge.
In avoiding vehicles, these escape patterns are counterproductive. A predator tries to collide with the prey, but a vehicle tries to avoid collision. A squirrel’s dodge confuses the driver or cyclist, who then tries to pass the animal on the opposite side of the initial feint, which is exactly the direction the animal ends up running in. The best way to avoid collision may be to just keep going in a straight line and let the animal dodge out of the way. A constant direction and speed is easy to predict, which lets the animal avoid being in the same place at the same time as the vehicle. Keeping one’s course and speed also avoids accident-prone sharp turns and sudden stopping.
If a predator was smart and knew about the dodging behaviour, then it would go opposite the initial dodge. But then the squirrel would benefit from not switching direction. In response to the squirrel just running in one direction, the predator should run in the direction of the squirrel’s initial movement, etc. This game only has a mixed strategy equilibrium where the squirrel randomises its direction and whether it dodges or not, and the predator randomises its response to the squirrel’s initial movement direction. Dodging takes more energy than just running to one side, so the dodge must have a benefit that outweighs the energy cost, which means that the predator must be less successful when the squirrel dodges. Some factor must make it difficult for the predator to swerve opposite the squirrel’s initial direction. For example, if most prey keep running in one direction instead of feinting, then the predator may be on average more successful when following the initial movement of the prey. The cognitive cost of distinguishing squirrels from other prey must be too large to develop a different strategy for chasing squirrels.
The same game describes dribbling in soccer to avoid a defender. It would be interesting to look at data on what proportion of the time the attacker feints to one side and then moves to the other, as opposed to just trying to pass around the defender in the initial movement direction. It is more difficult for both players to switch than to keep moving in one direction, but presumably the player with the ball finds it relatively more complicated than the defender. In this case, to keep the other player indifferent, each player only has to switch direction less than half of the time, but the defender relatively less frequently. If the attacker feints and the defender does not switch direction, then the defender looks clumsy and the attacker a good dribbler. Reputation concerns of soccer players (who are after all entertainers) may make them switch direction more often than a pure winning motive would dictate.
Similarly, soccer players may use flashy moves like scissor kicks more often than is optimal for winning, because the flashiness makes the player popular with fans.

Recovering faster from a sprint by jogging than by walking

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It seems that the panting and muscle weakness right after a sprint passes faster when I jog than when I walk or stand (the recovery I am talking about here is the minutes it takes to get back to normal breathing, not the days it takes for muscle soreness to disappear). I did not find empirical research on whether jogging actually speeds recovery from a sprint – it could be just my false perception. For this blog post, I will assume my perception is correct and speculate about why.
Faster recovery of breath when jogging seems counterintuitive, because jogging takes more power (energy per unit of time) than walking, so consumes the body’s cardiovascular output and nutrient reserves faster. The increased consumption should delay the short-term recovery. However, the perception of recovery need not be positively correlated with the whole body’s oxygen and glucose consumption, only with the CO2 reaching the chemoreceptors (either central in the brain’s respiratory centre, or peripheral in the carotid arteries and the aorta).
If the blood vessels in the legs expand during a sprint, and the blood pressure falls after a sprint faster than the blood vessels contract, then blood may pool in the legs and less of it may reach the chemoreceptors. Blood is forced up from the legs by the contractions of the leg muscles, which are more intense and frequent during jogging than walking. Therefore jogging may increase the venous return, leading to a better blood supply to the torso and the brain, which the latter perceives as faster recovery from exercise.
Even if the contractions of the leg muscles during jogging and walking had the same intensity and frequency, the group of muscles activated during jogging does not completely overlap with those working during walking. One muscle group may surround the major veins in the legs more closely, thus pump blood up more effectively.
There may be evolutionary reasons why the jogging muscles are better at stimulating venous return – faster overall circulation is needed during more intense exercise, for example when jogging compared to walking. Better venous return speeds up the circulation.
A mechanical reason why jogging may improve recovery from a sprint better than walking is that the jogging muscles overlap with the sprinting muscles more than the walking muscles do. If blood pools in the sprinting muscles and needs to be returned to the core, then contracting the jogging muscles forces blood out of the sprinting muscles better than contracting the walking muscles does.

Self-balancing computer game

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In both tabletop role-playing and computer games where players choose between different characters, some characters may be stronger than others when played optimally. This is undesirable in multiplayer games, because either most players will choose the stronger characters or some players will be handicapped by their weak character, which tends to reduce the enjoyment. Game designers spend time and resources “balancing” the game, i.e. changing aspects of the characters to give them all approximately equal strength. It is difficult to predict all possible ways a character may be played, so players may discover tricks that make a character significantly stronger than others. To counteract this, the game can be made self-balancing: the more players choose a given character, the weaker that character becomes. Then the discovery of ways to play a character better (giving additional strength) initially benefits the discoverer, but is neutralised with widespread imitation, analogously to innovative firms reaping monopoly profits initially from their patents, but eventually losing their competitive advantage to imitators.
The simplest way to self-balance is to subtract some measure of strength, e.g. health points, armor, attack points from the most frequently chosen characters. One in-game interpretation of this loss of strength to crowding is that each character channels power from some source (magic item, god, nature) and if more people channel a given source, then each of them gets less power. There are other ways to impose a negative congestion externality to achieve self-balancing.
One source of congestion-induced weakening is that in-game enemies (NPCs) fight better against characters they frequently encounter. This can be interpreted as learning (if the enemies flee before dying and later come back) or evolution (if the longer-surviving enemies multiply relatively more). In an evolutionary arms race, players pick characters that are strong against frequently encountered NPCs. NPCs vary in their resistance to different attacks and relatively more copies are spawned of those who last the longest under player attack.
Another congestion externality is a shortage of some resource that strengthens a particular class of characters. For example, equipment usable by that class may be in limited supply, in which case if many players choose that class, then they will find themselves under-equipped and weak. There could also be a shortage of materials for manufacturing the equipment, or a shortage of class-specific quests for gaining experience.
To make players (as opposed to NPCs or the game mechanics) the source of disadvantage to a frequently chosen class, the classes should have advantages over each other in a cycle, for example archers defeat riders, riders defeat swordfighters, swords defeat archers. In this case, if a class is frequently chosen, then this invites other players to choose another class that has an advantage over the frequent class, e.g. if many have chosen riders, then this creates an incentive to choose archers. Such a cyclical evolutionary dynamic has been observed in lizards (Rapid Temporal Reversal in Predator-Driven Natural Selection, Science 17 Nov 2006 Vol. 314, Issue 5802, pp. 1111).

On military bravery

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All countries and armed groups emphasize the bravery of their soldiers for propaganda purposes. Such claims are made regardless of whether there is any actual valour. Going to a dangerous situation or even certain death is not necessarily courageous, in particular if there is no knowledge of the danger or no choice. Are sheep going into a slaughterhouse brave? They are calmly walking to certain death, after all. But usually this is not ascribed to courage, but to ignorance. Analogously, soldiers used in early tests of the physiological effects of radiation exposure who were marched through an area of a recent nuclear explosion are not considered brave. They did not know the cancer risk.

If there is no choice, which usually means there are only perilous choices, then putting oneself in danger is not usually accounted brave. Jumping out of a burning building offers a higher probability of survival, so people do it despite the substantial risk of falling to death. When a sufferer of a painful terminal disease chooses euthanasia, this early death is commonly not considered brave. Some cultures even believe suicide to be a sign of cowardice. If a military has a well organized system for catching deserters and administering the death penalty to them (and their family in some regimes), then a soldier charging enemy machineguns is merely maximizing his survival probability. The enemy might miss, the firing squad rarely does.

The greater the probability of victory for one’s own side, the less attractive desertion becomes, because being caught is more likely. This explains the propaganda emphasis on own victories and the punishment of “defeatist talk” in wartime. The greater the military advantage of a party in an armed conflict, the less bravery its soldiers need.

Genuine bravery exists, but it is rare. Evolution favours cowardly bullies who attack the weaker (prey) and run from the stronger (predators). People who face no compulsion to fight in a war and know the dangers, yet still join, are brave. Freedom fighters (insurgents from the other side’s viewpoint) against a dictator qualify. With the caveat that only joining the fight initially requires bravery – after that, losing would mean being tortured to death by the dictator, so continuing the war is the safer option. Similarly, volunteering for the military requires some bravery (the more the greater the likelihood of being sent into danger), but once military law applies, desertion is usually more dangerous than the duty.

Military courage is proved for those who start the war as a weaker side against a stronger, if a continuing peace is not a slow death. Peasant revolts were often driven by hunger, meaning the participants may have perceived the probability of death from starvation as higher than the probability of being killed by the aristocrats.

People who have never faced an informed choice between a safe and a dangerous option may be “latently brave”, in the sense that given such a choice, they may exhibit courage. They are not proved brave, however, until they have made the choice. There are likely to be some latently brave people in the world’s militaries and armed groups. Probably a greater percentage than among the general population.

There are some proven brave folks even in the militaries of powerful countries, but the proof requires knowingly choosing a dangerous option when there is no future punishment for cowardice. For example, when nobody would know of the choice.

A topical question is whether suicide terrorists and other fighting religious fanatics are brave. Their behaviour may be driven by the fear of punishment either in the afterlife or by their fellow fanatics. It may also be due to ignorance – believing in an afterlife is like believing that one cannot really die and thus the danger is not real. In both cases, no courage is required for choosing death.

The belief in the impossibility of dying may even be literal – W.E.B. Griffin had a story of a witch doctor convincing the fighters of his tribe that his magic had made them immune to bullets. Great was the fighters’ surprise later… Their charge with spears against guns was not due to bravery, however.

Probability of finding true love

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The concept of true love has been invented by poets and other exaggerators. Evolutionarily, the optimal strategy is to settle with a good enough partner, not to seek the best in the world. But suppose for the sake of argument that a person A’s true love is another person B who exists somewhere in the world. What is the probability that A meets B?

There is no a priori reason why A and B have to be from the same country, have similar wealth or political views. Isn’t that what poets would have us believe – that love knows no boundaries, blossoms in unlikely places, etc?

Given the 7 billion people in the world, what fraction of them does a given person meet per lifetime? Depends on what is meant by “meets” – seeing each other from a distance, walking past each other on the street, looking at each other, talking casually. Let’s take literally the cliché “love at first sight” and assume that meeting means looking at each other. A person looks at a different number of people per day depending on whether they live in a city or in the countryside. There is also repetition, i.e. seeing the same person multiple times. A guess at an average number of new people a person looks at per day is 100. This times 365 times a 70-year lifespan is 2555000. Divide 7 billion by this and the odds of meeting one’s true love are thus about one in three thousand per lifetime.

Some questionable assumptions went into this conclusion, for example that the true love could be of any gender or age and that the meeting rate is 100 per day. Restricting the set candidates to a particular gender and age group proportionately lowers the number of candidates met and the total number of candidates, so leaves the conclusion unchanged.

Someone on the hunt for a partner may move to a big city, sign up for dating websites and thereby raise the meeting rate (raise number met while keeping total number constant), which would improve the odds. On the other hand, if recognizing one’s true love takes more than looking at them, e.g. a conversation, then the meeting rate could fall to less than one – how many new people per day do you have a conversation with?

Some people claim to have met their true love, at least in the hearing of their current partner. The fraction claiming this is larger than would be expected based on the calculations above. There may be cognitive dissonance at work (reinterpreting the facts so that one’s past decision looks correct). Or perhaps the perfect partner is with high probability from the same ethnic and socioeconomic background and the same high school class (this is called homophily in sociology). Then love blossoms in the most likely places.

Why messages of attraction are ambiguous

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There are many behaviours by which one human shows being sexually attracted to another – staring at them, running fingers through one’s hair, standing close, smiling at them, etc. Most of these are ambiguous, meaning they can be explained away by nonsexual reasons. Staring may be due to being lost in thought and looking absently at a single point, which happens to contain a person. Adjusting the hair could happen because the hair feels messy. One could randomly stand close to someone, smile because one is happy for unrelated reasons and so on.
There are obvious benefits of clear messages – no wasted effort chasing someone not interested, no awkward situations, no false accusations that one’s partner was sending signals of interest to someone else. Why has evolution led to messages of attraction that create doubt in the observers?
If someone’s sexual advances are unsuccessful, this is interpreted as a negative signal about the rejected person and lowers their chances in the future. Rejection makes one wonder what the rejecter knew about their admirer that is unattractive. If a person has characteristics that makes others reject them, the offspring of that person are likely to inherit these and also be unsuccessful in mating. Unsuccessful offspring mean the fitness of the rejected person is low, justifying rejecting them. This evolutionary mechanism is called Fisherian sexual selection. Because of it, nobody wants to be seen to be rejected. One way to hide rejections is to hide the wooing and if rejected, pretend to be uninterested anyway (sour grapes).
Someone attempting to cheat on their partner obviously does not want others to see their advances on another person. People gossip, so hidden signals with plausible deniability are useful.
Some people take advantage of those attracted to them (the advantage may differ for men and women), so it is good to send messages of attraction only to those who are attracted in return. Someone who is interested pays more attention to a person, so is more likely to notice ambiguous messages from them. Wishful thinking makes an interested recipient interpret mixed messages favourably. Of course there is a positive probability of a mistake, but the difference between the probability of interested people versus unintended recipients noticing a signal is greater for ambiguous than clear messages. This is like encryption – there is a positive probability of friendlies having lost the encryption key, but the difference between the probability of friendlies versus hostiles understanding the message is greater for encrypted text.
Dating websites have probably figured this out, because they allow private messages. An additional improvement may be self-destructing messages that can only be viewed once. This makes it harder for the recipient of a message to prove someone’s interest to others and thus lower their admirer’s reputation after rejecting them. Randomly generating messages of attraction and sending them to people would give plausible deniability to those who are rejected. The benefit of deniability must be weighed against the loss to the recipients of false signals.

Raising grandchildren, not children

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Currently in all species I know of, each generation raises its children, who in turn raise their children, etc. This can be described as an overlapping generations model where each generation lives 2 periods, receives resources from the old of the previous generation in its youth and transfers resources to the young of the next generation when old. There is another equilibrium: each generation raises its grandchildren, has its children raised by its parents, and the children in turn raise their grandchildren. Instead of transferring resources to the next generation and receiving them from the previous, transfer resources two generations forward and receive them from two generations back. There are an infinite number of such equilibria: for each n, transfer resources n generations forward and receive them from n generations back. There are of course practical problems with large n, because the organisms do not live long enough to meet their level-n offspring.

There are complaints in developed countries that childbirth is postponed in life to acquire education and start a career. A possible solution is transitioning to an equilibrium of taking care of grandchildren, together with having children at a young age so that the grandparents are still alive to see the teenage years of their grandchildren. However, the equilibrium transition from taking care of children to taking care of grandchildren means that one generation must raise both children and grandchildren. The equilibrium transition in the other direction is easy – one generation does not raise its children or grandchildren, because its children are raised by its parents and its grandchildren by its children. Any other equilibrium is less stable than the raising-children one, because it is difficult to transition to it and easy to transition away.

The equilibrium stability comparision is similar to the social security equilibria in overlapping generations. In one equilibrium, everyone saves for their own retirement and consumes their savings when old. In another, every generation when young pays the social security costs of the previous generation who is old at the same time. The transition from the saving equilibrium to the equilibrium of paying the previous generation is easy, because one generation gets its savings and the contribution from the young, while the young do not save and receive the contribution of the next generation. The reverse transition is difficult, because one generation does not get a contribution from the young in its old age, but has to finance the retirement of the previous generation when young.