Gene-Culture Coevolution Favours the Emergence of Traditions in Mate Choice through Conformist Social Learning

Imagine a world where how we choose our partners isn't just about who we think is attractive, but also about who everyone else is choosing. For a long time, scientists thought that for a "tradition" to form in mate choice (like a specific style of dress or a certain type of partner becoming popular), people needed a very sophisticated brain trick: conformity. This means you would have to actively ignore the minority and disproportionately copy the majority, like a crowd of people all suddenly deciding to wear red hats just because 51% of the crowd is wearing them.

This paper suggests that's not the whole story. The authors argue that when you mix culture (what we learn from others) with genes (what we are born with), the rules change completely. They used computer simulations to test this, treating female preferences as something learned from friends (culture) and male traits as something passed down from parents (genes).

Here is how they broke it down:

1. The Old Way (The Cultural Model)
In their first simulation, they acted like traditional cultural evolution experts. They found that for a tradition to stick, the "copying" had to be heavy-handed. You had to have that strong bias where if 60% of the group liked a trait, you had to like it way more than 60% to make it a lasting trend. It was like a snowball that only started rolling if you gave it a massive shove.

2. The New Way (The Gene-Culture Model)
In their second simulation, they added a twist: they separated what you learn from what you actually do.

• Learning: You might hear from your friends that "Type A" partners are great.
• Realizing: But when you go to find a partner, you can only choose from the people who are actually there.

In this scenario, they found that traditions could form even with simple copying. You didn't need that heavy-handed "disproportionate bias." Why? Because of a feedback loop between the genes and the culture.

The Analogy: The Dance Floor and the DJ
Think of it like a dance floor.

• The Genes are the dancers (the men).
• The Culture is the playlist (the women's preferences).
• The DJ is the social learning (telling people what song is popular).

In the old view, for a song to become a "tradition," the DJ had to scream, "Everyone dance to this song!" even if only a few people were dancing to it.

In the new view, the DJ just says, "Hey, this song is popular." The women (learners) hear this and want to dance to it. But here's the kicker: because the men (genes) are also evolving to be better dancers for that specific song, more men show up ready to dance to it. The song becomes popular not just because the DJ shouted, but because the dancers and the music reinforced each other. The popularity of the song made more dancers appear, and the presence of those dancers made the song even more popular.

The Bottom Line
The paper concludes that we don't need complex, super-conformist brains to create traditions in mate choice. If our learned preferences interact with the actual availability of partners (who are shaped by their genes), simple copying is enough to create strong, lasting trends.

This changes how we understand cultural evolution. It suggests that many behaviors that rely on resources (like finding a mate) can become traditions much more easily than we thought, as long as the "learning" and the "reality" of the situation work together. It's a call to stop looking at culture and genes as separate things and start seeing them as a team that builds traditions together.