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Passions Within Reason Book Summary – Robert Frank

What you will learn from reading Passions within Reason:

– How Emotions bring future pain into the present and why that is important.

– The Impulse-control problem and why feeling guilt reveals someones trustworthiness.

– How love has evolved to solve the commitment issues involved in human relationships. 

Passions Within Reason Book Summary:

This is a fantastic book which can be quite challenging in parts but definitely worth reading if you are into evolutionary psychology.

In this book Robert Frank delves into the role that emotions play in everyday life and offers a theory for why they have evolved in humans. 

To distil Frank’s overall message:

Being motivated by emotion is often an advantage. There are many problems that purely self-interested persons simply cannot solve. For example, how can they make themselves attractive for ventures that require trust? How can they credibly threaten to walk away from unfair transactions that will increase their wealth? Or how can they deter aggressors when retaliation would be obviously costly?

These questions reveal that a rational, self-interested person would be one thing that would massively put them at a disadvantage. They would be predictable.

The solution? Emotions that cause us to act outside of our narrow interests. An example, guilt motivates telling someone the truth even though lying would be the rational thing to do. 

If you’re interested in learning more then read on then be prepared, it’s dense.


Important principles for co-operation – Repeat transactions:

The great enforcer of morality in commerce is the continuing relationship, the belief that one will have to do business again with this customer, or this supplier, and when a failing company loses this automatic enforcer, not even a strong-arm factor is likely to find a substitute. 


We need enforcement otherwise people take things into their own hands:

Where the force of law is weak, cycles of attack and revenge are familiar. They pervade life in the Middle East today and have been recorded throughout human history. Probably very few of us have never experienced the impulse to seek revenge. And yet the costs of acting on it are often ruinous.


The Role of Emotions:

If Smith knows Jones will be driven by emotion, not reason, he will let the briefcase be. If people expect us to respond irrationally to the theft of our property, we will seldom need to, because it will not be in their interests to steal it. Being predisposed to respond irrationally serves much better here than being guided only by material self-interest. 

Consider a person who threatens to retaliate against anyone who harms him. For his threat to deter, others must believe he will carry it out. But if others know that the costs of retaliation are prohibitive, they will realize the threat is empty. Unless, of course, they believe they are dealing with someone who simply likes to retaliate. Such a person may strike back even when it is not in his material interests to do so. But if he is known in advance to have that preference, he is not likely to be tested by aggression in the first place. 

Consider, too, the person who “feels bad” when he cheats. These feelings can accomplish for him what a rational assessment of self-interest cannot-namely, they can cause him to behave honestly even when he knows he could get away with cheating. And if others realise he feels this way, they will seek him as a partner in ventures that require trust. 

The distinguished sociobiologist Robert Trivers wrote, “. . . 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.’ What this means is guilt is an emotion that uses the risk of your actions becoming common knowledge to motivate you to behave in a certain way. 


Emotions as guides to our behaviour:

Our concern here will be with the role of such emotions as guilt, anger, envy, and even love. These emotions often predispose us to behave in ways that are contrary to our narrow interests, and being thus predisposed can be an advantage. 

At least partly on the basis of such clues, we form judgments about the emotional makeup of the people with whom we deal. Some people we sense we can trust, but of others we remain ever wary. Some we sense can be taken advantage of, others we know instinctively not to provoke. 

Whether people honor their agreements when they expect to interact repeatedly with us is obviously important. But in much of life, we are concerned instead with how they behave either in fleeting encounters or in ones where their behaviour simply cannot be observed. These cases, after all, are the ones that seriously test a person’s character. In them, an honest action will be one that, by definition, requires personal sacrifice. 


The Commitment Model

The term commitment model is shorthand for the notion that seemingly irrational behaviour is sometimes explained by emotional predispositions that help solve commitment problems. The commitment problem, arises when it is in a person’s interest to make a binding commitment to behave in a way that will later seem contrary to self-interest. 

The critical assumption behind the commitment model, again, is that people can make reasonable inferences about character traits in others. By “reasonable inference” I do not mean that it is necessary to be able to predict other people’s emotional predispositions with certainty just fairly accurately. 

The commitment model, emphasises the role of emotions in behaviour. The rationalists speak of tastes, not emotions, but for analytical purposes, the two play exactly parallel roles. Thus, for example, a person who is motivated to avoid the emotion of guilt may be equivalently described as someone with a “taste” for honest behavior. 

It is clear, at any rate, that these sentiments can alter people’s incentives in the desired ways. Consider, for example, a person capable of strong guilt feelings. This person will not cheat even when it is in her material interests to do so. The reason is not that she fears getting caught but that she simply does not want to cheat. Her aversion to feelings of guilt effectively alters the payoffs she faces. 

For the model to work, satisfaction from doing the right thing must not be premised on the fact that material gains may later follow; rather, it must be intrinsic to the act itself. Otherwise a person will lack the necessary motivation to make self-sacrificing choices; and once others sense that, material gains will not, in fact, follow. Under the commitment model, moral sentiments do not lead to material advantage unless they are heartfelt.


The commitment model and Honesty:

The honest individual in the commitment model is someone who values trustworthiness for its own sake. That he might receive a material payoff for such behavior is completely beyond his concern. And it is precisely because he has this attitude that he can be trusted in situations where his behavior cannot be monitored. Trustworthiness, provided it is recognisable, creates valuable opportunities that would not otherwise be available. 

Someone who is caught cheating on one occasion creates the presumption he may do so again, which can obviously limit his future opportunities. From observations like these springs the maxim, “Honesty is the best policy.” On this commonly held view, even a merely prudent person-one with no “real” concern about doing the right thing-does best simply to pass up all opportunities for cheating, no matter how seemingly attractive. By so doing, he will develop a reputation for being honest. 

Not having a bad reputation is not the same thing as being known to be honest. The kinds of actions that are likely to be observed are just not very good tests of whether a person is honest. 


The Commitment problem in the relationship market:  

The parallels between the rental housing market and the market for personal relationships are clear. The exchange model views each participant in the relationship market as searching for the best partner his or her endowment will command. 

Information about prospective partners is notoriously incomplete, much more so than in the rental housing market. Even if a person knew exactly what he or she was looking for, many of the relevant traits would remain exceedingly difficult to discover. 

The difficulty that confronts the exchange model of intimate relationships may thus be summarised as follows: Because search is costly, it is rational to settle on a partner before having examined all potential candidates. Once a partner is chosen, however, the relevant circumstances will often change. (A more attractive partner may come along, a partner may become disabled, and so on.)  

The resulting uncertainty makes it imprudent to undertake joint investments that would otherwise be strongly in each party’s interest. In order to facilitate these investments, each party wants to make a binding commitment to remain in the relationship. But practical difficulties stand in the way of their doing so through the legal system. 

The Solution – Love:

The person whose marriage is based on love has an inherent advantage in solving this problem. Love for one’s partner imposes an additional cost on the affair, one that is experienced right away. Because the emotional cost of betraying a loved person occurs in the present moment, there is at least some chance it can outweigh the immediate attractions of the affair. The purely rational materialist, who does not experience this immediate cost, will have greater difficulty implementing his pledge. 


Behaviour and Reward Mechanisms:

Material incentives are by no means the only force that governs behaviour. Even in biological models, where these incentives are the ultimate concern, they play no direct role in motivation. Rather, behaviour is directly guided by a complex psychological reward mechanism. 

The fit between the behaviours favoured by the reward mechanism and those favoured by rational calculation is at best imperfect. The reward mechanism provides rules of thumb that work well much of the time, but not in all cases. Indeed, when environmental conditions differ substantially from the ones under which the reward mechanism evolved, important conflicts often arise. 


Rational Calculations are input into the reward mechanism:

The critical point, for present purposes, is that rational calculations play only an indirect role. Suppose, for example, a hungry person calculates that being fat is not in his interests, and for this reason refrains from eating. His rational calculation has clearly played a role, but it is an indirect one. 

It is still the reward mechanism that directly governs his behavior. The rational calculation informs the reward mechanism that eating will have adverse consequences. This prospect then triggers unpleasant feelings. And it is these feelings that compete directly with the impulse to eat. Rational calculations, understood in this way, are an input into the reward mechanism. 


Cultural Training and Sentiments:

Moral sentiments could not emerge under the commitment model, however, if there were not substantial economies of scale in social interaction.  

According to the commitment model, the survival of trustworthiness derives in part from a tendency to be receptive to cultural training. 

In thinking about the separate roles of nature and culture, I find it a helpful metaphor to imagine that nature’s role is to have endowed us with a capacity that is much like a gyroscope at rest; and that culture’s role is to spin it and establish its orientation. Each of these roles is indispensable. 


The Impulse-control Problem:

The strength of the link between reputation and character will depend on the degree to which people find it difficult to resist immediate rewards. If impulse-control is only a minor problem, the inference will be weak. 

So, if someone is emotionally predisposed to regard cheating as an unpleasurable act in and of itself-that is, if he has a conscience he will be better able to resist the temptation to cheat. 

Although moral sentiments may sometimes lead to the wrong behaviors in purely material terms, they help solve the omnipresent impulse-control problem. This may well be a decisive advantage. 


Emotions shift the reward mechanism into the present:

The problem, as in the cheating example, is that the gains from a tough reputation come only in the future while the costs of vengeance-seeking come now.  

The matching law thus again suggests an impulse-control problem. A person may realise that it pays to be tough, yet still be tempted to avoid the current costs of a tough response. Being predisposed to feel anger when wronged helps solve this impulse-control problem. As with feelings of guilt, anger helps shift the relevant future payoffs into the current moment. In cases where reputational considerations weigh in favour of action, the angry person will be more likely to behave prudently than the merely prudent person who feels no anger. 


The Matching Law:

The matching law tells us that the attractiveness of a reward increases sharply as its delay approaches zero. 

From this it follows that people who are concerned only about material rewards will often cheat (fail to retaliate, etc.) even when it is not rational to do so. 

The gains from cheating, again, come now while the costs come later, if at all. Thus, when we see that a person has never been caught cheating, we have reason to believe that his behaviour is motivated, at least in part, by nonmaterial rewards. And herein lies the kernel of truth in our belief that reputations matter. 

As Stanley Jevons, for example, described it: To secure a maximum of benefit in life, all future events, all future pleasures or pains, should act upon us with the same force as if they were present, allowance being made for their uncertainty … But no human mind is constituted in this perfect way: a future feeling is always less influential than a present one. 



The signals we should be concerned with are ones that take place between parties whose interests are at least potentially in conflict.  

For example, with the signals transmitted between two parties who confront prisoner’s dilemmas or other commitment problems. If the parties are self-interested, statements like “I will not defect” are problematic in the sense that both people’s best interests are to say co-operative statements. Thus this conveys no information. 


The Derivation Principle:

A second important general signal principle  is that the trait that serves as a signal does not usually originate primarily for that purpose. This so-called “derivation principle,” first described by the Nobel laureate ethologist Niko Tinbergen. 

The derivation principle does not apply to signals that result from the conscious actions of persons. These can be both purposeful and forward-looking. 

The derivation principle applies only to passive signals, especially ones that arise from natural selection. It does not apply to active, or purposeful, signals. 

Note that Tinbergen’s derivation principle does not apply in the case of product guarantees. Unlike the toad’s croak or the dung beetle’s basic appearance, product guarantees didn’t originate for some purpose unrelated to the signaling of product quality. They are an active signal, not a passive one. This distinction is important, again, because some of the signals emerged through natural selection, others through purposeful action. 


The Full Disclosure Principle of Signalling:

A third important principle illustrated by the toad example I will call the “full-disclosure” principle. It says that if some individuals stand to benefit by revealing a favourable value of some trait, others will be forced to disclose their less favourable values. 

The general message of the full-disclosure principle is that lack of evidence that something resides in a favoured category will often suggest that it belongs to a less favoured one. Stated in this form, the principle seems transparently simple. And yet its implications are sometimes far from obvious. 


Small toads with smaller croaks will respond even when they show that they are smaller. This happens not because the small toads want to call attention to their smallness by croaking. Rather, they are forced to do so in order to keep from appearing smaller than they really are. 

The full-disclosure principle derives from the fact that potential adversaries do not all have access to the same information. In the toad case, the asymmetry is that the silent toad knew exactly how big he was, while his rival could only make an informed guess. Similar asymmetries give rise to a host of important signals between people. 

The full-disclosure principle will also influence our understanding of how moral sentiments are communicated to potential adversaries. It suggests, for example, that it will generally be difficult to exempt oneself from the signalling process entirely. 

For if, say, the expression of emotion is a reliable clue to the presence of these sentiments, its lack of expression will then be an indication of their absence. Where size mattered, even the smallest toads were forced to participate in the croaking contest. Likewise, where moral sentiments are important, failure to convey them will summon an uncharitable interpretation of one’s position. 


We use peoples behaviour as signals of their intrinsic motives:

Do you know someone you believe would be unlikely to cheat you even if he could do so with no possibility of being detected?  

Assuming you do, note again how difficult it is to offer factual evidence in support of your belief. You cannot rationally have made this inference from experience, because if this person had previously cheated you in a similar situation, you could not have known about it. Once again, a “yes” answer in this thought experiment means you believe you can fathom the inner motives of at least some other people. 

The prisoner’s dilemma experiment lends support to our intuition that we can identify unopportunistic persons. That we can, in fact, do this is the central premise upon which the commitment model is based. 


Kagan’s Motivating Emotions:

His principal claim is that, while specific moral norms are enormously varied and complex, they are supported by a limited number of simple, highly uniform emotional capacities. 

Stressing that his labels are less important than the underlying concepts, he lists the following five basic categories of unpleasant emotion: 

  • Anxiety (as, for example, over physical harm, social disapproval, or task failure);
  • Empathy (especially with those in need or those at risk);
  • Responsibility (especially for causing harm to others);
  • Fatigue/ennui (following repeated gratification of a desire);
  • Uncertainty (especially from poorly understood discrepant events and inconsistency of beliefs).

The desire to avoid the various unpleasant affective states, in Kagan’s scheme, is the principal motivating force behind moral behaviour. People will try to avoid actions, motives, and qualities that make them feel afraid, sorry for those less privileged, anxious, bored, fatigued, or confused. The specific actions or circumstances that trigger these emotions will depend heavily on cultural context. But the motivating emotions are always and everywhere the same. 


Why Children develop the behaviour of crying when their parents leave:

Without the capacity to retrieve stored mental images and compare them with the present, the child is unable to perceive the discrepancy between the caregiver’s presence and absence, and thus has no basis for becoming distressed when the caregiver leaves the room.  

Once he/she develops that capacity, however, she becomes aware that there has been a change. Because of her existing attachment to the caregiver, it is a change that matters. Being able to do nothing about the discrepancy results in her distress. 


Standards and Emotion:

The most important feature of Kagan’s argument, in terms of its relevance to the validity of the commitment model, is that standards evoke an emotional response. A standard, he emphasizes, is thus different from a convention, such as “Always drive on the left side of the road in England.” Both standards and conventions are norms, but conventions lack emotional coloration. With standards, however, there is an emotional conviction that the choice really matters. 

The fact that standards evoke an emotional response is of course what accounts for their motivational significance. People will risk life and property in defense of a standard, but will do little on behalf of a convention. 


Feelings and Language:

Confronted with these feelings and behaviours, the language center seems to feel a compelling need to explain them. Gazzaniga views the language module as our centre of rational consciousness, obsessed with rationalising all that we feel and do. He stresses, however, that the explanations it invents are not always the right ones. 

McClelland suggests that if forces beyond awareness do in fact play a major role in binding partners together, we should not be surprised that the reasons people give for pairing bear little relation to their true motives. What we are getting, in effect, is the language module’s attempt to account for feelings and behaviours motivated by parts of the brain that cannot speak for themselves. In a culture that places a premium on rationality and the pursuit of self-interest, it seems hardly surprising that the explanations we hear are often of the rationalist mould.