Dads vs Cads — an origin story

We are not a classic pair-bonded species. We are not a polygamous, tournament species either…. What we are, officially, … is a tragically confused species. (Robert Sapolsky)

Robert Sapolsky is spot on with his observations. Studies show that the proportion of mostly monogamous vs promiscuous people is roughly 50:50, with men only having a slightly higher disposition towards promiscuity. Some researchers have interpreted this as two relatively stable evolutionarily stable strategies or bifurcating equilibria. However, there is more to this story. Different equilibria may well be caused by different evolutionary environments. The connection between promiscuity and caddishness may be obvious for us, but it is well-grounded in life-history strategy (formerly known as r/K-selection). Species with shorter life histories invest more in mating effort than in parenting effort (e.g. rats), whereas it is the other way round with species with longer life histories (e.g. elephants). As far as homo sapiens is concerned, we couldn’t be much more K-selected. Most of us take care of our offspring for 20+ years.

However, when it comes to paternal investment human cultures differ widely. Any way you look at it, life-history strategy predicts a correlation between sociosexuality and low paternal investment:

r/K theory and life history studies would predict the following traits:

This pattern is very consistent and we can observe it in the Hadza (foragers) and their neighboring Datoga (pastoralists). In the Hadza (monogamous, reproductive rate 4–5 years) fathers take an active role in child-rearing (alloparenting) and also see women as egalitarian partners. The Datoga (polygamous, reproductive rate every two years) hardly take part in child-rearing activities which they consider women’s work. The differences between the two tribes fit the pattern of r/K selection quite well.

What we can see here is an unpredicted correlation between caddism and dominance hierarchy. Whereas foragers like the Hadza are egalitarian (also towards women and children), pastoralist societies are hierarchically structured.

Occasionally Hadza women get married to Datoga men. However, unsurprisingly, these marriages usually don’t last long and the Hadza women return to their tribe after a short period. I have argued that our temperaments were shaped by our ancestral modes of substances and that these temperaments have been mostly kept apart by the kind of assortative mating seen above. The majority of people living nowadays would be farmer types. Early farmers had lower lifespans than foragers, but higher lifespans than pastoralists:

Farmer types tend to be much more monogamous than pastoralist types, however (unless high up in the hierarchy). Farming requires higher levels of intra-group cooperation and as a consequence, there is less direct competition over females. Farmer types (often conservatives) tend to be very family-oriented and they are the ones who the modern nuclear family model suits best, with traditional roles for men (provider) and women (caregiver). They are also the ones who have most likely the most stable marriages.

Of course, this doesn’t mean that all forager types (think Mark Zuckerberg) are faithful dads and all pastoralist types (think Hugh Heffner or Rod Stewart) are philandering cads. People generally adapt to the norms of their culture. However, if you see a guy in a Ferrari, you know that guy has a tendency to invest more in mating effort than in parenting effort. He is likely a pastoralist type. If you see a guy spending a lot of time on the playground with his children he invests a lot in parenting effort. He is also more likely a farmer or forager type.

For more, check out my book Dating and mating for the confused and completely clueless

Originally published at on July 5, 2021.