PhD thesis passed


Jason Collins


November 16, 2015

A couple of months ago I was notified that my PhD thesis had been passed (full pdf here). I have posted about each chapter before:

  1. The Evolutionary Foundations of Economics

  2. Economic Growth and Evolution: Parental Preference for Quality and Quantity of Offspring

  3. Population, Technological Progress and the Evolution of Innovative Potential

  4. Sexual selection, conspicuous consumption and economic growth

  5. Evolution, Fertility and the Ageing Population.

Here are links to the three (anonymised) examiner reports - one from an economist at an Australian university, another from a US based economist, and a third from a biologist. A few excerpts follow. First, from the Australian-based economist on the overarching thesis:

While there is certainly some truth in the evolutionary hypothesis it is in my view far from the complete story. Culture and institutions certainly also play their part. The industrial revolution in Britain was very much a cultural phenomenon (Morkyr, Jacob) – you do mention that culture get encoded in DNA, but you do not pursue it in depth. As you mention Clark and Galor are into high fertility in the upper class; however, I am not at all compelled by their hypothesis. The landed class was not innovative, it was lazy and land was mostly inherited. Institutions may also have played a role — according to Acemoglu and Robinson this is the only thing that matters.

While I believe that natural selection forces may have been important in the past they are effectively put out of force in welfare states. It is not exactly the rocket scientists that get numerous kids in today’s advanced countries but often those we don’t want too many of, and that may well lower the innovative activity substantially and lead to an inverse relationship between population growth and productivity growth. The increasingly obese society also appears to go against the fitness hypothesis.

And from the biologist:

[P]apers are cited if they have been inspirational for constructing his argument, but in places the message is extrapolated far beyond what the original paper intended to show, while contrary evidence or work emphasizing other aspects (e.g. phenotypic plasticity as opposed to genetic change) is not paid much attention to.

Given that we in reality know very little about whether, say, it was genes causally linked to thrift and hard work that caused economies to shift in recent times (a definitely interesting idea [attributed to another scholar cited in the thesis] — but one could also quote more objectionable traits that can documentably lead to getting ahead at the expense of others), or the extent to which demographic transition involves genetic change or, instead, simple behavioural plasticity responding to quality-quantity tradeoffs using old rules but with new outcomes when the environment changes, it would have been refreshing to see what each model produces “as a whole”, together with a discussion of the likelihood of each particular outcome (including but not limited to the best-fitting case). A thorough examination of how robustly the outcomes follow from the assumptions is part of the current standard of eco-evolutionary modelling.

Now that the thesis is complete, I have mixed feelings about the process. I sense I would have learnt more if the process was to produce a book with less focus on formal modelling and more on piecing together the evidence on the overall argument. As an example, I am not sure the model in the conspicuous consumption chapter adds much to an intuitive argument that draws on other theoretical work - although the process of putting the model together did help me come to grips with what was going on.

I’m not planning to do much more work in the style of academic papers. Partly that reflects my existence outside of the world of academia - I’m not facing any publication incentives. I’ll try to get the as-yet unpublished chapters published, and I have two other papers in progress, but that will likely be it.

Otherwise, I’m hoping to climb back on to the blogging bandwagon, which has been on and off over the last year for a range of personal reasons. Blogging is a much more satisfying way of communicating than producing academic articles. As a start, my first published paper receives around 400 abstract views and 30 downloads per year (I expect largely due to click-throughs from the blog), compared to an average of several hundred blog visitors each day. And as a medium for collecting and distilling my thoughts, blogging is more effective. So hopefully there will be more posts in the near future.