XVI.6 When choosing their behavior, organisms do not go by the sum of expense and profit, expressed in units of fitness, but by a similar sum of negative and positive emotions

Based on the results of ethological observations and experiments and also based on introspection, it can be said that, when deciding, an individual is usually not motivated by how much real profit or real loss the behavior brings and very often even not by how much profit or loss it gets in units of pleasure and distress. In many situations, individuals may behave quite irrationally from the both points of view. How the individual will behave in a particular situation is, in the end, decided not by a rational calculation but an irrational emotion (Fehr & Gachter 2002). The consequence of this is that the behavior of real organisms may sometimes differ significantly from the behavior that could be expected according to game theory.

An example that simply illustrates this situation is a psychological experiment called the “ultimatum game”. There are two players and the following rules: Player A gets $ 100 from the experimenter. He can give a voluntary amount of this sum to player B. If player B finds the sum too small, he can refuse it; in that case both players will get nothing. The game only has one round, i.e. the players cannot expect a reward or payback for their behavior in future rounds. According to game theory, and rational thought as well, the most appropriate strategy for player A is to offer player B an arbitrarily small sum, e.g. $ 1 and, from player B’s viewpoint, to accept this arbitrarily small sum with gnashing teeth. The problem is the teeth gnashing. Because of the negative emotions caused by the unfair sharing of the sum, player B is very likely to refuse the money. He will punish the opponent, although he will fail to profit as well – he will get nothing instead of at least a small sum of money. But emotionally, he will feel much better – he will bask in the feeling that his unfair currish opponent, the goddamn scrooge, also got nothing {11691}. Because player A can almost certainly expect such behavior from player B, he is probably going to split the amount much more fairly, often 1:1 (Fig. XVI.7) {10828}. In this case, player A gets a bonus – a pleasant feeling that he again showed the world how righteous he is; for some persons,  of course, a similar bonus can be a feeling that he has just out-maneuvered his opponent by offering him such a small sum and he finally accepted it (while gnashing his teeth so nicely).



Fig. XVI.7 Altruistic punishment and its impact on sustained cooperation. In the course of the experiment, the test subjects (the players) played two series of 6 games of common good. At the beginning of each game, 4 players received 20 monetary units and each of them could privately deposit any amount, i.e. 0-20 units, in a pool and keep the rest. The experiment leader then counted the total deposited amount, augmented it 1.4-fold and distributed it equally among the players, irrespective of how much each of them had deposited. For each deposited unit only 0.4 unit was returned to the players but, providing that they all fully cooperated and deposited their 20 units, they would in the end gain 32 units instead of 20 in one game. At the beginning of the experiment, the players knew that there would be 6 games in total and that they would never play against the same player twice. The players did not know how the other players played in previous games. The common good game was played in two variants, with and without punishment. In the game without punishment, the amount from the pool was distributed among the players at the end of each game. In the game with punishment, prior to distribution, the amount each player had deposited was disclosed (under a nickname) and the players had the chance to punish each other: they could impose sanctions on each other at the amount of 0-10 units. If player A imposed a sanction of, for example, 1 unit on player B, 1 unit was deducted from his account and 3 units were deducted from player B’s account. Consequently, the punishment was an expression of altruism – it meant a financial loss for the punisher, while he was never going to play against the punished player again, meaning that he could not benefit financially from any potential improvement in stingy player B’s behavior. Despite these conditions, players often punished their stingy (non-cooperating) partners in the game: 84 % of players punished at least once during the 6 games, 34 % more than five times and 9 %  more than ten times. Sanctions were quite high – if a player invested 14-20 units less than the other three players in the game, he received an average sanction of almost 30 units. Half of the players played 6 rounds of the common good game without punishment (a) and half with punishment (b); then they were informed that another 6 rounds would follow, this time the very last game indeed, of the other variant than that which the group had played originally. A total of 240 players participated in the game and each of them earned around 27 units on average. The chart clearly shows that average cooperation (average number of units deposited by the players in the pool) gradually decreased in the game without punishment while, in the game with punishment, cooperation was much higher and gradually increased even further over time. After Fehr and Gächter (2002). 


            At first glance, it may seem that the existence of emotions that force us to behave irrationally is disadvantageous in many situations for organisms, and the question arises as to how this mechanism could arise in evolution by natural selection. The truth is that individuals who follow their emotions rather than rational calculus can be much more successful in the long term. From the long-term viewpoint, evolution was able to optimize the situations and the intensity with which external stimuli will launch our individual emotions. Because the optimization occurred through the objective mechanism of natural selection, i.e. only what really increased the biological fitness of its bearer could become fixed in the population, evolution included, in the final calculation, even those expenses and profits that the individual could not or was not able to include in its rational calculation. For example, if we behave altruistically in the ultimatum game with a total stranger, we can not guess in advance how often someone else will learn about our “noble and selfless“ behavior, how much it will improve our reputation and how the good reputation could influence our fitness in the future  (Fig. XVI.8). In contrast, evolution has had enough time to try this out in practice and, according to the results of the individual “experiments”, it could set the appropriate launching levels for emotions  that would direct individual behavior in similar situations in the future.


Fig. XVI.8 The impact of a potential change in reputation on sustained cooperation. Nineteen six-member groups of students played anonymously or, more precisely, under allocated nicknames, two alternating experimental games: the indirect reciprocity game (grey symbols) and the common good game (black symbols). In the first case, each of the six members was once a potential donor and once a potential acceptor of approximately 1.25 euro in each round. The potential donor could decide whether he would give this amount to a particular acceptor. If he decided to do so, he lost 1.25 euro and the acceptor received 2 euro. The donor knew that the particular acceptor would never be assuming the role of donor towards him in the next rounds, and thus would not be able to pay him back for this move. The moves of all the players were made public after each game (under nicknames of course). In the common good game, each player could deposit or not deposit 1.25 euro in a common pool in each round. After the money had been deposited, the experiment leader doubled the deposited amount and distributed it equally among all the players, irrespectively of whether they had contributed to the pool or not. Each player’s move was again published after each game. If a given group played the indirect reciprocity and the common good games alternately from the beginning, the players maintained a relatively high level of cooperation (dotted line). However, if the group played eight rounds of the common good game first (where the player’s reputation cannot affect the results), cooperation rapidly decreased amongst the players (full line). In the subsequent eight rounds of the indirect reciprocity game, their cooperation increased. The experiment ended with four rounds of the common good game. If the players knew in advance that these were the last four rounds and that there would be no more indirect reciprocity game (triangles), their cooperation rapidly decreased. If they were not given this piece of information (squares), the level of cooperation remained very high. After Milinsky and Krambeck (2002).

            Most populations contain enough genetically conditioned variability in emotions and, moreover, particular traits can be transferred culturally. Consequently, mechanisms directing emotional behavior can, with the help of the Baldwin effect and genetic assimilation, develop relatively rapidly and adapt to changes in the environment. Nonetheless, the evolution of particular controlling mechanisms and thus the evolution of individual behavior in the population may, in some cases, fall behind changes in the environment the organisms currently live in. This mainly concerns the evolution of humans, whose environment, and namely its most important part from the fitness point of view – social environment – develops at the speed of lightning compared to the rate of biological evolution.  It is therefore possible that our emotional world is optimized for the environment our species lived in for the past tens or hundreds of thousands of years and did not manage to adapt, for most of us, to the changes that came with overcrowding and life in numerous and anonymous groups. This means some behavioral patterns that are forced on us by our emotions can actually be disadvantageous for our fitness; they can be truly altruistic, i.e. they may objectively lower the inclusive fitness of the carrier to the profit of non-related individuals in the population.

            The conclusions of evolutionary psychology sketched in this chapter may seem cynical. In any case, it is necessary to think about some of the less visible consequences of the phenomena described in the previous paragraph. They indicate that, amongst other things,our inner world is to a considerable degree autonomous, independent of the outer world we live in. What fills us with pleasant feelings does not necessarily contribute to increasing our fitness, and what is unpleasant does not necessarily harm us. It may seem degrading that this can only be a consequence of the inability of evolution to adapt the speed of evolution of our emotions to the speed of development of our environment. Objectively, it is more important that evolutionary psychology shows us that we are not the prisoners or hostages of our biological nature, but free individuals that are independently responsible for their decisions and behavior. Which behavior is right or wrong, the ethical question must be decided by ourselves; we cannot plead that behavior that does us good emotionally is objectively correct (increases the average fitness of members of our species). As a kind of compensation for increased efforts and personal responsibility we can, in return, get a warm feeling that we are not living in a cynical world where every altruistic deed is only altruistic for effect, but that we and our neighbors can behave (and most likely often do behave) really selflessly.

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The classical Darwinian theory of evolution can explain the evolution of adaptive traits only in asexual organisms. The frozen plasticity theory is much more general: It can also explain the origin and evolution of adaptive traits in both asexual and sexual organisms Read more
Draft translation from: Evoluční biologie, 2. vydání (Evolutionary biology, 2nd edition), J. Flegr, Academia Prague 2009. The translation was not done by biologist, therefore any suggestion concerning proper scientific terminology and language usage are highly welcomed. You can send your comments to flegratcesnet [dot] cz. Thank you.