Has Human Evolution Been Culturally Driven?

The ever spectacular author Matt Ridley proposes a thesis where our genes evolved from cultural developments.

Mr. Ridley writes,

The human genome provides penetrating and unexpected insights into human individual and collective history. Among them is the counterintuitive idea that genes are at the mercy of experience – that what we do in our lives affects which genes are switched on and off.

A stressful experience, for example, can make you more vulnerable to infection, because stress hormones indirectly alter the switches that control the expression of genes.

So, far from genes being the cause of how we act, the new understanding sees them as just as much a consequence of how we act. This subtler view of genes has yet to colonise the popular imagination.

On a much longer, evolutionary timescale, the same reversal of causation is necessary.

We now know that many genetic changes in human beings are driven by cultural ones, at least as much as the other way round.

For example, the ability to digest lactose as adults spread among Africans and Europeans because of dairy farming, rather than vice versa.

Read the rest of the fascinating theory here