Christopher X J. Jensen
Associate Professor, Pratt Institute

Great conversation at my Columbia University Population Biology Seminar talk

Posted 14 Mar 2016 / 0

It was a great honor to speak on this past Monday, March 7th, 2016 as part of Columbia University’s Population Biology seminar series. I gave a talk entitled “Breeders, Propagators, & Creators: Culture, Biology, and the Future of Human Evolution” to a small group of biology faculty and students from a nice diversity of different local educational institutions. The talk was a partial synopsis of my work-in-progress book, Breeders, Propagators, & Creators. I gave an overview of my basic argument and then looked more closely at a particular question: To what degree do parents propagate their culture to the children they raise?

Giving a talk like this is an amazing opportunity. Whereas most talks — even when they are labeled as part of a seminar series — feel very unidirectional, speaking at this event felt much more like a dialogue. Most talks end with a couple of questions, and sometimes these questions lead to new insights on the topic, but generally when I speak I get little idea of how my ideas were received. But the tradition of this seminar series is apparently to emphasize engagement with the ideas presented, and there was a really valuable and far-ranging discussion that occurred after my talk. This is exactly what I need, as I am still figuring out which of my ideas for this book project seem reasonable and viable.

In the discussion that followed my talk, we explored a bunch of issues that I need to consider including in the book. One issue is why women tend to have fewer offspring when they are given access to education: is it that they are immediately “converted” into being more prolific propagators of cultural ideas, or is this simply a shift in their reproductive strategy associated with achieving a more stable economic livelihood? Another issue that I was able to discuss openly was the risk that my inquiry would be interpreted as an exercise in eugenics, as I express concern that the tension between cultural and biological evolution might be leading to our biological evolution. For the first time I floated my main concern — that what we might be losing is part of the human genetic diversity that makes our uniquely-specialized societies function — and this idea seem to be generally well-received. Of course at this point I have no idea if there’s any sort of biological selection that’s being caused by our demographic transitions to lowered fertility, but as I go looking the nature of my target is important.

Another interesting idea that was floated was that lowered fertility might be a form of altruism, perhaps kin-directed. It’s funny that this was suggested because I certainly spend a lot of time thinking about altruism but have not had the instinct to consider the lowered fertility of economically-developed countries to be “self-sacrifice for others”. That possibility seems pretty unlikely to me because the recipients of any such altruism seem to be very global: arguably, lowered fertility in places like North America, Europe, and parts of Asia benefit populations in higher-fertility areas like the Middle East or Africa by opening up economic opportunity for would-be migrants. But to consider this a form of altruism — especially if you label that altruism as adaptive — seems pretty far-fetched to me. My working hypothesis is that humans are trading off between two forms of fitness — cultural and biological — and that those “losing” the biological competition are “winning” the cultural competition, and vice versa.

The value of these seminars is magnified by the fact that they are followed up by a nice buffet dinner that encourages further interaction. As the only full-time biologist at Pratt, I am so starved for interaction with biology colleagues, so it was nice to be able to sit down with peers from several other area universities. We talked a lot about the challenges of teaching introductory biology courses, a challenge that I do not face but one that is pretty standard for most faculty at teaching-intensive institutions. I also was introduced to a really interesting explanation of why people might become celibate nuns or priests: doing so might maximize inclusive fitness by compelling non-celibate siblings to have more offspring (for example, by adhering to the Catholic prohibition against using birth control). If this theory is viable, it is a compelling case for gene-culture coevolution: by becoming an exclusive propagator of ideas, nuns and priests maximize the chance that they will effectively spread church doctrine to their siblings, who are then more likely to pass on shared genes. This was the first time I had heard of religious celibacy being explained from a kin-selective perspective.

Thanks so much to Kathleen Nolan and Alison Cucco for inviting me to give this talk and for organizing such a great evening!

A Major Post, Breeders, Propagators, & Creators, Cultural Evolution, Gene-Culture Coevolution, Human Uniqueness, Kin Selection, Parenting, Population Pressure, Public Outreach, Public Policy, Reproductive Fitness, Sex and Reproduction

Leave a Reply