Lionel Page wrote in this 2022 book:
* the brain represents only 2% of an average adult body’s weight, but 20% of its consumed energy.
* In a famous study, Schkade and Kahneman (1998) found that while people tend to believe that living in sunny California would make them happier, people living in California are not happier. Schkade and Kahneman called this the “focusing illusion”, the idea that we will be very happy with the next move to a better location, a better job, a better-looking car and so on. But in the end, “Nothing … will make as much difference as you think.”
* Success at attracting a partner depends on the ability to look like a good option relative to the other options available. …there are very good reasons why we care about our relative success: information and the benefits of relative standings. These reasons help us understand which group of people we are likely to choose as a comparison point to judge our achievements as successes or failures.
* “Under certain conditions natural selection favors … altruistic behaviors because in the long run they benefit the organism performing them.” (Robert Trivers)
* “Multiparty altruistic systems increase by several-fold the cognitive difficulties in detecting imbalances and deciding whether they are due to cheating or to random factors. One simplifying possibility that language facilitates is the formulation of rules of conduct, cheating being detected as an infraction of such a rule. In short, selection may favour the elaboration of norms of reciprocal conduct.” (Trivers 1971)
* prosociality (the fact of caring about others’ interests) seems to be widespread across cultures.
* even purely self-interested players would rationally engage in sustained cooperation over time. The only requirement for this to happen is that the probability of future interactions is high enough.
* we care about others’ outcomes; we care about others’ intentions; and we act as if caring about these others and their intentions is required by rules of morality that are objective (i.e., universally true, not relative to people or situations). …Evidence of reciprocal behaviour shows that people tend to be kind with people who are kind to them and unkind with people who are unkind to them.
* people seem motivated to do the right thing even if, most likely, nobody is affected by their decision.
* A person who never cooperates would certainly be a very poor player in social interactions, missing out on the opportunity of gains from cooperation and unable to get consistent benefits from uncooperative behaviour (because other people are not pushovers). The best way to play in repeated interactions is to care about others and about what they get.
* The past record of a player acts as a reputation, which will determine whether people decide to cooperate with the player or not.
* we are cautious about choosing our acquaintances. When doing so, we have to form a view on their likelihood to cooperate in the future (Baumard et al. 2013). Here again we can use other people’s reputation, based on their past actions, to guide such decisions.
A key aspect of social interactions is that there are many of them and that circumstances change frequently, meaning that while interactions are repeated, the specific payoffs and risks are going to vary over time. The future circumstances in which we will be in a situation where our fate depends on the actions of our partners are hard to foresee. It creates an incentive to look carefully for partners who are inclined to cooperate and on whom we may be able to rely on, whatever happens. In lay terms, we will look for people who show good character in their past actions… that people care about others’ intentions explains a lot about the intricate patterns of social interactions. For example, it creates incentives to exchange information about others’ actions and motives to find out what they are really up to. Such information is useful to ascertain whether somebody
can be trusted as a cooperating partner. A typical form of such information exchange is gossip, which pervades social interactions across human societies… A person who does not take time to think before deciding to help is seen as nicer than somebody who takes a long time to make the same decision to help. In social interactions, splitting
something equally without clearly looking at everyone’s cost and benefits is often preferred to the feeling of awkwardness associated with engaging in the required accounting… Mutual gifts allow potential partners to signal to each other an intent to engage in long-term cooperation, in opposition to a care for shortterm costs and benefits.* In social interactions, punishments of norm violators often start with mockery, signalling to the culprits that they deviated from the norm. If John never pays for his friends’ drinks in a pub while they frequently pay for his, he risks ending up being at the receiving end of jokes about his stinginess. If mockery does not work, stauncher punishments are bound to take place, like the simple withdrawal from future cooperation. In the case of John “forgetting” to take his turn paying for drinks, others may end up not inviting him to their social drinks any more.
* moral preferences are often experienced as truth rather than preferences. An action that violates a fairness rule will be perceived as unambiguoulsy bad not because we have some preference over it but because it is bad. This feeling of objectivity is easy to understand in ethical philosophies supported by religious beliefs where a deity can give
an objective nature to a moral rule. But even secular ethical philosophies have relied on the notion of objectivity, such as the idea that individuals have natural rights.* you may trust people more in business transactions if you know that they believe that unfair deals are forbidden by some objective rule… If… people understand moral behaviour as the unconditional respect of rules, observing whether somebody follows moral rules in one context is a good predictor of what this person will do in another context. Furthermore, the objectivity of the rule helps people to coordinate their expectations.
* there are very good reasons why people would follow commonly understood and shared rules. And acting as if these rules are objective may also help facilitate cooperation. …even though large cities now offer some interactions with strangers that are likely to be one-shot, it is a very novel and unusual type of interaction on the time scale of human history. Most of our ancestors have lived in small groups of up to 150 people for tens of thousands of years.
* There is no contradiction between our moral attitudes and an evolutionary explanation. Evolution should not necessarily select for selfish preferences. Instead, it is more likely that evolution led us to have moral preferences to help us navigate successfully the opportunities of repeated cooperation with others. …because we have these
moral feelings that are genuine (proximal cause), the idea of explaining them as instrumental (ultimate cause) can feel distasteful.* Humans are social animals; they are pretty helpless alone and face large potential benefits from cooperation. It is therefore reasonable to expect that they will have evolved preferences helping them interact with others in ways that can be mutually beneficial. These considerations explain why people care about others’ fate, why they care about others’ intentions, and why they care about following fairness norms that, in a given social context, point to commonly accepted ways to share the benefits and costs from cooperation.
* neuroscience has shown that the brain regions activated when observing another person’s emotion, such as pain, overlap with those activated when experiencing these emotions themselves
* in many strategic situations, it can hurt you to have too many choices at your disposition.
* Anger can be helpful in a wide range of situations where it creates a credible threat that deters other people from taking advantage of you. …People are willing to engage in costly behaviour to retaliate when they feel they have been wronged. While this could be seen as irrational at first sight, it provides a benefit: it makes your threat of retaliation credible, because people know you are likely to carry on a threat if you have angry feelings… An even better solution than showing signs of anger when one is wronged is to build a reputation for anger and retaliatory behaviour in order to deter others from even trying to wrong you. Building such a reputation makes sense in situations where the rule of law is fragile and where opportunities of wrongdoing against you are frequent.
* Prisoners who are not part of a group risk ending up at the bottom of this hierarchy. Low positions in the prison’s social order may lead to being the target of systematic violence. In such an environment, some criminals engage in acts of self-harm, such as lacerating their arm with a knife, to build a reputation of irrationality and unpredictability.
* An effective strategy to make a threat of retaliation credible is to convince your opposition that you are not rational and could very possibly retaliate disproportionately in case of limited aggression. An important condition for it to work is for you to be able to send credible signals of anger to inform the other player that you would very likely act upon your threats.
* The emotion of guilt, with the visible cues it generates, credibly signals to others that one is trustworthy.
* “It is possible that the common psychological assumption that one feels guilt even when one behaves badly in private is based on the fact that many transgressions are likely to become public knowledge” (Robert Trivers)
* like anger and guilt, the strength of the feeling of love can bind an individual’s behaviour in a way that eliminates some moves. Love can act as a commitment device… When in love, people feel and act as if their partner is the only person they value in the world. They not only neglect other possible partners; they often purposely stay away from them.
* the people ready to sacrifice themselves in these situations were willing to do so for a group to which they belong and that they represent… Members of ethnic and cultural groups can go to great cost to mark their identity to a group. They frequently continue to follow norms from their groups, even when they live in foreign countries. They may show great care for key symbols of their group like a flag or anthem… The feeling of being part of a group, of belonging to a group, can raise strong emotions that do not seem to be simply about moral or religious values. On the positive side, there are feelings of elation when sharing positive moments as part of a crowd: singing in a church, cheering after one’s team victory. There are also feelings of pride when one’s group is successful (or when some members of one’s group are). On the negative side, there are feelings of anger against others who seem to hurt or disrespect one’s group.
* Individuals do not seem to go out of their way often to harm the interest of members of other groups. Such behaviour is mainly seen in situations where there is a conflict with the other group. In absence of conflict, individuals favour the members of their own group but act in a neutral way towards members of other groups…
* group membership does not just influence behaviour; it also influences perception. Once part of a given group, it seems that people overestimate how much people from other groups are alike… people look like different individuals in your own group, but they tend to seem alike in other groups.
* Adopting cultural symbols and following specific cultural practices can act as visible signs of membership to ingroup as well as to out-group individuals. Belonging to a group often requires behaving in a certain way, not in others. The disrespect of such symbols and practices by members of the group can raise suspicion about their allegiance to the group. Some practices may seem inconsequential at first sight, like what to eat or what to wear. But imbued with a group membership meaning, these practices can become a litmus test of group loyalty. Hence, even those group members who do not care so much about the practices themselves may carefully respect them, in order not to raise doubts about their attitude towards the group.
* When having to choose between identities, a person takes into account the status associated with each identity. Shayo proposes that when choosing an identity, an individual will trade off the benefits of adopting a group identity given the relative status of the group and the costs of adopting this identity, which is harder if the individual’s characteristics are far away from the average characteristics of the target group.
* identification with a national identity that has a higher average status and a greater ethnic homogeneity may have seen its relative appeal grow. This explanation is in line with the observation that the growth of nationalist parties has largely benefitted from the migration of voters originally supporting left-wing parties with redistributive policies
* Groups opposed to each other, like sports fans, ethnic groups or political factions, can express hatred at each other in a way that seems not to make sense in modern societies. People engaged in violent group conflicts are often perceived as senseless. But another way to look at it is that this propensity to be swept by such feelings is likely part of who we are. It is a ghost of our ancient times, where readiness to stick to one’s group and violently fight other groups was key for survival… Our emotional
apparatus is likely designed to accompany a greater level of antagonism than would be optimal now.* “Most things that seem irrational don’t seem so irrational once you understand signalling theory.” — Geoffrey Miller (Twitter post, 9 October 2019)
* Humans are equipped with the most complex language among all animals on earth. It allows us to communicate our knowledge and ideas to others. But human communication does not take the form of a simple exchange of clear statements between people. In many cases, people use not words but actions to communicate with others. Some other times people do not say explicitly what they want to say (e.g., innuendos, euphemisms). These features of communication seem strange and irrational only if we ignore that our means of communication are primarily designed to negotiate our interactions with others. In this process, transparent communication is sometimes not enough to influence others, and it is sometimes not desirable when people may react adversely to our intentions.
* The “quirkiness” of human interactions can generally be understood as good responses to the true nature and complexity of social situations.
* The need to manage others’ impressions arises when two conditions are met. First, others have imperfect information about us; second, the beliefs others have about us matter for our prospects.
* If you consider a heterosexual couple, the asymmetry in parental investment in offspring means that women are usually more wary of the sincerity of the stated dedication of potential male partners than the reverse… The time spent by a man in a courtship is a credible signal of interest because it is costly. Since courtship is generally somewhat socially transparent, a man usually does not court several women at the same time. Courtship therefore signals a man’s willingness to forego alternative opportunities in terms of partnership. Courtship also frequently features gifts to the courted woman such as flowers, or jewellery. Sozou and Seymour (2005) modelled this interaction as a signalling
game. A potential male partner signals his dedication by making costly gifts to his intended female partner. The gifts need to be costly to signal a credible intent from a long-term partnership (a man usually does not make such gifts repeatedly to other women). But Sozou and Seymour also note that these gifts will have, most often, low resale value (you cannot sell flowers, and the resale value of a piece of jewellery is relatively low). This apparently peculiar characteristic makes sense from the man’s perspective: these types of gifts protect men from possibly being taken advantage of by women collecting valuable gifts without a real intention of becoming a partner.* Engaging in any talk takes time (and also presents some cognitive costs). Hence, through short costly acts of discussions, people can signal to each other their shared consideration.
* “Those who know they are deep strive for clarity. Those who would like to seem deep to the crowd strive for obscurity” (Nietzsche). The obscurity of some writing is often just a signalling trick used by writers to look good.
* “When people speak, they often insinuate their intent indirectly rather than stating it as a bald proposition. Examples include sexual come-ons, veiled threats, polite requests, and concealed bribes.”
* “human communication involves a mixture of cooperation and conflict”
* People tend to exhibit systematically self-serving biases in their beliefs. They tend to think that they are better, smarter, nicer than they are. They attribute their success to themselves and their failure to external factors. They rationalise their errors and misdeeds but cast a critical judgement on others’ missteps. Surely, it is a sign that people are just poor at forming judgements about themselves and the world. In contrast to this view, we can explain these belief distortions by the fact that evolution likely selected us to form not accurate beliefs, but beliefs that can be useful. Research has shown that overconfidence, over-pessimism and warped reasoning may be selected features
of our cognition, giving us advantages in a range of situations.