The Theory of Evolution by Natural Selection

We think that we have a decent understanding of how biology evolves over time. A certain group, a certain population, has a set of traits. With each successive generation, new traits will appear due to random genetic mutations. If these gene mutations result in traits that make the individuals more successful at surviving and producing children, then over time those genes and traits become more prominent in that population.

The surrounding environment influences the traits of the group. This is the theory of evolution by natural selection proposed by Charles Darwin. For example, a population of brown desert beetles that attempt to live in a nearby forest will easily be picked off by predators because their brown color stands out among the green shrubbery. If by chance, a few beetle offspring are born with a green pigmentation they will be able to blend in with the foliage of the forest and be less visible to predators. Therefore, they can survive in that environment and reproduce. Over time, there will be a population of brown desert beetles and a population of green forest beetles.

How does cultural evolution affect biological evolution?

Culture, the collective beliefs, behaviors and practices that a group shares among its individuals also changes over time. It evolves. How does culture evolve though? Biological evolution is a byproduct of environmental pressure and random chance. Can cultural evolution be viewed the same way? How much does conscious effort or “manufactured cultural traits” affect cultural evolution? Can culture only evolve “naturally” or can an individual or small subgroup force their desired cultural traits onto the population? If so, how long do these “manufactured” cultural traits normally last?

Also, certain cultures can influence biology. Biology can influence culture. What should we make of these facts? Cultural evolution can create evolutionary pressure just like sexual selection. What are some examples of cultural evolution? Is this good or bad?

One example of culture influencing biology exists in a tribe in Panama. The Kuna tribe of Panama has one of the highest occurrences of albinism in the world. In this tribe, people with albinism are seen as highly intelligent and believed to have magical powers.  Therefore, people with this trait are highly revered in their culture. Thus, they have a higher likelihood of producing children. Albinism, as far as we know, does not provide biological advantages in most environments or at least very few. In fact, people with albinism are more sensitive to sunlight, become sunburned easily, and even may have vision problems. In most cases, these traits are disadvantageous, but because of cultural pressure albinism is more prevalent among the Kuna.

Biological evolution occurs unilaterally, only from parent to child. Cultural evolution has the capability to move unilaterally and horizontally from parent to child, child to parent, parent to parent, child to child, neighbor to neighbor, stranger to stranger. Keeping in line with the mechanism of biological evolution, theoretically, ideas and practices that confer some advantage would win out against competing ones.

What circumstances aid or hinder the survival of new cultural trends?

Every so often, by random chance or due to external forces, a new idea or practice emerges. One, in order for this new idea to be able to compete it must emerge in a society that allows the observation of new things. Conclusively, those societies heavily steeped in traditions and those that suppress the voices of certain groups may suffer from cultural stagnation. Two, for this new entity to become prevalent it must provide some advantage to the group which may first be demonstrated at an individual level. For example, instead of risking life or injury climbing a tree to obtain a piece of fruit, one may build a ladder. Others will see the benefit of using a ladder, its use will spread, and now this group will have a culture of ladder use. If though, climbing trees was a part of a belief that climbing trees makes one strong or proves one’s strength, then the easier use of a ladder may not proliferate.

Social Norms and Social Change: Dr. Cristina Bicchieri

I’ve actually been sitting on this idea and post for over a year and a half. I came back to it maybe once or twice. Recently, I attended a talk by Dr. Cristina Bicchieri, a philosophy professor, at the University of Pennsylvania who focuses on social norms and how they change. In a nutshell, she believes that people who change practices known as social norms tend to be either on the periphery of their social groups/networks or in the center. Without going into too much detail, different conditions such as 1) how a potential influencer views the risk of not following a social norm or doing something different from the group and 2) how much individuals within a group pay attention to what others do, affect when and how people may be able to change social norms.

Coincidentally, I decided to revisit this post a few days after the talk and realized that Dr. Bicchieri’s ideas and the idea of cultural evolution were related. I figured I would mention it here. Also, for many social norms to change, there must be an underlying shared feeling among the group that the social norm should change. It is when someone else is viewed acting on said belief that everyone else soon follows. I checked out Dr. Bicchieri’s book Norms in the Wild: How to Diagnose, Measure, and Change Social Norms and will hopefully write more about her work soon.

Photo Credit: Artastic at the St. Patrick’s Day Parade by William Murphy via Flickr (CC BY-SA 2.0)