Evolved Preferences

Robin Hanson (hanson@hss.caltech.edu)
Tue, 15 Apr 1997 12:33:23 -0700 (PDT)

If people like us dominated a rich and powerful future civilization,
what a glorious place it might be. They would value the things we
value, and so we stand a good chance of approving of their choices
regarding space exploration, scientific advance, body modifications,
individual freedoms, ecological preservation, spiritual insight, and
industrial advance.

But will our future descendants want what we want? Or will
evolutionary pressures change the distribution of values in our

The following two papers offer useful insights into the evolution of

Ingemar Hansson, Charles Stuart, "Malthusian Selection of Preferences",
American Economic Review, June 1990, V.80 No. 3. pp.529-544.

Lawrence Blume, David Easley, "Evolution and Market Behavior",
Journal of Economic Theory, 1992, V.58, pp.9-40.

The Blume & Easley paper analyzes the investment values selected for
by asexual reproduction. It finds that such evolution selects for
investors with logarithmic (and hence risk-averse) utility of wealth,
minimal time-discount (i.e. maximal patience), and Bayesian beliefs
with the smallest relative entropy to the truth.

The Hansson & Stuart paper tries to infer the gender and age specific
time discount values that were an equilibrium in our tribal past.
They note that on average sexual reproduction in a stable population
should prefer a discount rate of a factor of 2 per generation (which
fits with historic interest rates), but find that for tribal humans it
varies with age and gender. Young males, for example, discount the
future heavily, in contrast to children and men over 35.

I don't have a cite, but I think there are also good reasons to think
that young males should be risk-takers rather than risk-averse. On
average though one would expect only slight risk-aversion from sexual
reproduction, except for small genetic populations.

I also have a theory that young males should be more optimistic than
Bayesians; the better they think of their prospects the more likely
they are to fool young women into thinking highly of their prospects.

As we become better at exchanging information in ways other than via
sexual reproduction, it seems the longer time-horizon of asexual
reproduction should win out. This suggests a future of very patient
risk-averse asexual Bayesians, in contrast to the impatient optimistic
risk-taking young males who dominate science fiction.

Robin D. Hanson hanson@hss.caltech.edu http://hss.caltech.edu/~hanson/