Day 4: Guilt, cheating, and why monogamy won — Understanding Emotion

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Just like other emotions we can actually understand guilt, love, and revenge. I have so much to say about this as this is my topic of interest and I would like to go deeper into it. Guilt is two-fold: it prevents you from cheating, and it signals to others that you have a conscience so they can trust you. Robert Frank argues that people known to have conscience are more trusted. Then comes the harder question: why is guilt attached to romantic emotions? The answer involves helpless babies, paternity uncertainty, social reputation, and shared responsibilities. But if guilt keeps us loyal, why does cheating still happen? Because the mate-seeking drive never fully switched off. And if polygamy is the evolutionary default, why did monogamy win? Because polygamy destabilizes societies at scale. Finally, these emotions are double-edged swords. Unrequited love is one of nature's cruellest punishments. But if guilt were easy to fake, no one would trust it, and the whole system would collapse.

I have so much to say about guilt because this is my topic of interest. I would like to go deeper into it than the book does
There are at least two stories of guilt. First: it stops you from cheating. Second (Robert Frank): it makes others trust you. Both are evolutionary strategies
I can understand guilt in transactions. But the harder question is romantic relationships. What prevents someone from leaving their partner for a more attractive one?
Four evolutionary drivers keep romantic partners loyal: helpless babies, paternity uncertainty, social reputation, and reciprocal investment
People still cheat because the 'I can get better' mate-seeking drive never switched off. That drive itself is an evolutionary feature
Only 3-4% of mammals are monogamous. 83% of human cultures permit polygamy. But polygamy fails at scale because it destabilizes societies
These emotions are double-edged swords. Unrequited love is surely one of nature's cruellest punishments. We feel too much guilt and shame when things do not work out
If guilt were fakeable we would not trust guilt itself and the entire point of it would have been pointless. Guilt works because it is genuine and costly

Two Stories of Guilt

Guilt is at least two-fold. There are two separate evolutionary stories for why it exists, and both are convincing

Story 1: guilt as deterrent — this is the obvious one. If you have a conscience, the thought of the guilt you would feel afterwards is enough to prevent you from cheating in the first place. You do not need to actually experience the guilt. The anticipation alone stops you. This is guilt working inward, on yourself
Story 2: guilt as trust signal (Robert Frank) — Robert Frank has a different take. He argues that people who are known to have a conscience are more likely to be trusted by others. It is not just about stopping yourself from doing bad things. It is about other people seeing that you have the capacity for guilt, and therefore choosing to cooperate with you. That is wild
I agree with Frank's argument. Think about it concretely: if I do my job correctly, the people working under me will benefit. They will do their jobs better. Then those who use the products we have built will benefit as well. By the end, the entire society benefits. And hence I will benefit from it. The conscience is not just a brake. It is a signal that you are safe to cooperate with
The fact that the thought of cheating is accessible to me but I still do not act on it is itself an evolutionary process. Evolution did not remove the desire to cheat. It layered guilt on top of the desire. The temptation exists, but the restraint wins
It is also important to show the guilt. Not just feel it. It is important for other people to recognise that you have a conscience so that you can be 'trusted'. Guilt that nobody sees has limited social value. The display matters as much as the feeling

Guilt in Romantic Relationships

I can understand the nature of guilt in transactions. But I want to think about the things that romantic partners do. What prevents them from cheating on their current partner and going to a more attractive one? Why is guilt attached to romantic emotions?

The answer lies in four parts. Each one is a separate evolutionary pressure that keeps romantic partners loyal
Helpless babies — human babies are dumb. They require an enormous amount of care compared to other species. A human infant cannot walk, feed itself, or survive alone for years. If we had cheating partners who abandoned their families, the babies raised by single parents would have had a very low survival rate. Two committed parents meant the child was far more likely to reach adulthood. Guilt about abandoning your partner is evolution protecting the offspring
Paternity uncertainty — males can never be 100% certain of paternity. Unlike females who always know the child is theirs, a male has no biological guarantee. Pair-bonding with emotional locks (guilt, jealousy, love) gives males reasonable confidence that they were investing in their own genes. Without these emotional locks, males would have no incentive to stay and provide resources. The guilt of cheating is part of the glue that holds the pair bond together so that both parents invest in children they believe are their own
Social reputation — since you do not cheat, it gives you social validity. You become more socially connected. Other members of the group see you as reliable and trustworthy. In ancestral environments, being socially connected meant access to food, protection, and allies. Chances of survival are higher. Cheating risks destroying your reputation and being excluded from the group
Reciprocal investment — when you are paired, you give responsibility to others and this makes you more survivable. Shared responsibilities. One partner hunts while the other guards the children. One forages while the other builds shelter. This division of labour only works if both partners stay committed. Guilt enforces the deal. If you cheat, you break the reciprocal arrangement and both partners lose the survival advantage

The Mate-Seeking Drive

If guilt is such a powerful restraint, why do people still cheat? Because evolution kept another drive running in parallel

People still cheat because the mate-seeking drive never fully switched off. The fact that we still have an 'I can get better' instinct is not a bug. It is there for getting more evolutionary advantage. Evolution is not clean engineering. It layers conflicting drives on top of each other
The guilt system says: stay loyal, protect the bond, invest in your offspring. The mate-seeking system says: there might be a genetically superior partner out there. Both systems run at the same time. Cheating happens when the mate-seeking drive temporarily overpowers the guilt system
This raised a question for me about social reputation and reciprocal investment. If both are real benefits of staying paired, but the mate-seeking drive still exists, then would not polygamy be the natural state? Why is monogamy the default at all?

Why Not Polygamy?

If the mate-seeking drive is real and monogamy is just one strategy, wouldn't polygamy be the norm? Turns out for most of the animal kingdom, it is

This was my own question after thinking about social reputation and reciprocal investment above. If loyalty gives you social validity and pair-bonding makes you more survivable, but the mate-seeking drive still exists, then would not polygamy be the natural default?
The numbers are surprising. Only 3-4% of mammals are actually monogamous. And 83% of human cultures studied historically permit polygamy. So monogamy is the exception, not the rule
But polygamy is not widespread in practice because it does not work on a larger scale. Three specific problems keep breaking it

Polygyny: One Male, Multiple Females

The most common form of polygamy. It works for high-status males but destabilizes the entire society

In polygyny, high-status males have lots of access to women, giving no chance to lower-status men for reproduction. These excluded men do not just quietly accept it
Having no prospect of a mate or family increases their chance of turning to crime and destabilizing the society. A large population of young men with no reproductive prospects is one of the most dangerous things a society can produce
'Societies that enforced monogamy were more internally stable and could find larger, more cooperative armies, outcompeting those with polygamous cultures'
Monogamy won not because it is morally superior. It won because monogamous societies were more stable and could coordinate at larger scales. This is group-level natural selection in action
Resource dilution — on top of the instability problem, one father for multiple children across multiple mothers means resources get spread too thin. Each child gets less attention, less food, less protection. In ancestral environments where survival was already difficult, diluting paternal investment across many offspring reduced the survival chances of each one

Polyandry: One Female, Multiple Males

Sounds good on paper. It is beneficial for offspring and for the female. But it completely fails for males, for three separate reasons

The idea: one female pairs with multiple males. Each child could have a dedicated father. And the female gets more partners to propagate her genes. On the surface this looks like it could work
Males do not care for others' children — males are not designed to care about children that are not their own. The paternity uncertainty problem from earlier gets even worse in polyandry. If a male does not know which child is his, his motivation to invest drops to near zero. Why spend years raising a child that might carry someone else's genes?
Statistically unproductive for males — a female can have only one offspring per year regardless of how many partners she has. But a male can have several offspring per year with different partners. So from the male's evolutionary perspective, polyandry is a terrible deal. He is investing maximum resources for minimal reproductive output. He would be better off leaving and finding another partner
Societal factors — cultural norms, inheritance systems, and power structures all reinforce patterns that do not favour polyandry. Property, lineage, and status have historically been tracked through the male line. Polyandry breaks all of those systems

The Final Answer on Polygamy

Every form of polygamy has a structural failure that prevents it from scaling

If we had poly relations, the trade-off is really high. Polygyny destabilizes society by creating excluded men. Resource dilution weakens offspring survival. Polyandry fails because males have no incentive to invest
Monogamy is not the most exciting strategy, but it is the most stable one. It gives each person a realistic shot at a partner, keeps paternal investment focused, and produces societies that can cooperate at scale

The Double-Edged Sword

These emotions are powerful precisely because they are hard to escape. That is both the feature and the cost

But these emotions are double-edged swords. As you can know, unrequited love is surely one of nature's cruellest punishments. You cannot choose to stop loving someone just because they do not love you back. The emotion does not have an off switch
We tend to feel too much guilty, too ashamed, and waste so much time when things do not work out. A breakup can destroy months or years of someone's life. Grief over a lost relationship can feel physically painful. These are not proportionate responses to the situation. They are disproportionately intense because evolution built them to be
But if the condition were opposite, where 'moving on' was easy, then the credibility of these emotions would have reduced dramatically. Think about it. If you could leave a partner and feel nothing, then your commitment means nothing. The fact that leaving hurts is what makes staying meaningful. The pain is the proof that the bond is real
The fact that we can 'show' guilt is the reason for someone to trust us. If moving on were easy, that trust signal would be worthless. Nobody would believe your loyalty if they knew you could walk away without feeling a thing
But what if we could just fake the guilt? If guilt was fakeable, we would not trust the guilt itself, and hence the entire point of guilt would have been pointless. The whole trust mechanism only works because guilt is genuine, involuntary, and costly. You cannot just decide to feel guilty. You either do or you do not. And that involuntary nature is exactly what makes it a reliable signal
This connects back to the tears discussion from Day 3. Tears are hard to fake. Guilt is hard to fake. Emotional pain is hard to fake. Evolution specifically selected for signals that are difficult to counterfeit because only unfakeable signals can be trusted