traits – Success Across Cultures

Biologists say that behavior is ultimately determined by natural selection.

This is because genetic structures are constructed according to the mental processes and learned patterns and responses to different environments.

As Richerson and Boyd, authors of Not By Genes Alone: How Culture Transformed Human Evolution, note: physiological changes that shape behavior are evolutionary.

Take bird migration, for instance.

Instead of passing winter in harsh environments, birds have acquired their migratory behavior according to evolutionary physiological reactions.

The brain has formed evolutionary strategies across time to send hormonal signals that trigger annual migration to warmer climates.

So, while genes may determine the traits and behaviors best suited to the environment, the environment has helped shape these genes.

Where does culture come into play?

Culture is part of the environment, especially where humans are concerned.

Culture Drives Human Evolution

Taking the environment’s impact on evolution a step further, in a study by the University of Maine, culture was found to drive human evolution even more so than genetics.

According to the 2021 study by researchers, Tim Waring and Zach Wood, humans adapt to their environment and challenges in their environment via culture – in the form of learned knowledge, skills, and practices –more effectively and at a faster pace than through genetics.

One reason for this “special evolutionary transition” is that the cultural transfer of knowledge is flexible and fast when compared to genetic transfer.

Waring notes that:

“Gene transfer is rigid and limited to the genetic information of two parents, while cultural transmission is based on flexible human learning and effectively unlimited with the ability to make use of information from peers and experts far beyond parents.”

This results in a stronger adaptation via cultural evolution than genetic evolution allows.

The researchers also argue that culture’s group-oriented nature produces more group-oriented evolution as well.

Ways in Which Humans Have Evolved

How have humans evolved via culture?

Humans have adapted in several key ways over the millennia.

These include:

Capacity for social learning
Predisposition to be cooperative
Capacity to collaborate
Diminishing aggression

Genetics and culture work together to adapt behaviors, but as Waring and Wood’s research suggests, culture is becoming even more influential on the evolution of human behavior.

As Waring concludes:

“This research explains why humans are such a unique species…We are slowly becoming ever more cultural and ever less genetic.”

Language is culture. Food is culture. Customs are culture.

They are all taught. They are all shaped and communicated across generations through group orientation and primary socialization.

In the book, Not By Genes Alone: How Culture Transformed Human Evolution, authors Peter J. Richerson and Robert Boyd explain that some scientists argue that culture and human behavior cannot be tied to evolutionary theory and biology, quoting the concept of nature versus nurture.

Culture is something created via nurture, while biology is formed by nature.

An individual’s concept of time, her values and customs, her language – all of this is formed by the environment in which she grows up.

It is nurtured.

An individual’s eye color, his height, any genetic disease he may have – all of this is formed by genes.

It is the result of nature.

Considering this, many argue that evolutionary theory does not come into play in regards to learned behaviors that are shaped by the environment.

As we’ve discussed in many blog posts, cultural behaviors – and most other human behavior – is learned; therefore, the argument is that biology has little to do with creating it.

But Richerson and Boyd suggest that this is not the case, due to the symbiotic nature of genes and their environment.

Genes & the Environment Interact

Genes are not blueprints specifying an organism’s final draft.

Instead, the genetic information stored in an organism interacts with the environment around it while the organism is developing.

As Richerson and Boyd describe it:

“Genes are like a recipe, but one in which the ingredients, cooking temperature, and so on are set by the environment.”

And like any recipe, the traits of the organism will vary based on the differences in the environment.

Some traits are more affected by environment than others.

For instance, most humans develop two ears, despite the environment they’ve grown in, but depending on their nutritional environment during youth, they can develop different growth and health outcomes into adulthood.

Environmental differences can also cause differing behaviors in organisms that are genetically the same.

In such circumstances, the environment is the direct cause of different traits and behaviors.

And because culture is both a part of the environment and a reaction to it, while genes are the evolutionary response to past environments, neither can be removed from the equation.

They are symbiotic.

We’ll take a closer look at the degree to which genes and culture influence human behavior next week.