A two level mutation-selection model of cultural evolution and diversity.

Area of Science:

• Evolutionary biology
• Social sciences
• Mathematical modeling

Background:

• Cultural evolution involves trait transmission between individuals (vertical/horizontal) and can be influenced by individual success or idea transmissibility.
• Understanding the interplay between individual and idea-level selection is crucial for explaining cultural change.

Purpose of the Study:

• To develop a mathematical model exploring the dynamics of cultural evolution at individual and idea levels.
• To investigate factors influencing whether cultural evolution enhances individual adaptation or leads to maladaptive trait spread.
• To examine the impact of these dynamics on cultural diversity.

Main Methods:

• Mathematical modeling of cultural trait transmission and frequency dynamics.
• Analysis of factors including trait interchange, selective pressures, new trait production, memory capacity, and population size.
• Distinguishing between fitness-enhancing and 'selfish' cultural traits.

Main Results:

• Identified conditions under which cultural evolution is primarily driven by individual-level success versus idea-level transmissibility.
• Demonstrated that increased cultural interchange can decouple evolution from adaptation and reduce diversity.
• Highlighted the potential for 'selfish' ideas to spread irrespective of their adaptive value.

Conclusions:

• Cultural evolution's trajectory depends on the balance between individual and idea-level selection pressures.
• Inter-population cultural exchange may hinder adaptive evolution and decrease cultural diversity.
• The study provides insights into the conditions favoring adaptive versus maladaptive cultural change.