The
ultimatum game is an experimental economics game in which two parties
interact anonymously and only once, so reciprocation is not an issue.
The first player proposes how to divide a sum of money with the second
party. If the second player rejects this division, neither gets
anything. If the second accepts, the first gets his demand and the
second gets the rest.
In theory a "rational" player should accept whatever is offered when there isn’t a repeated iteration. Reality is different. From The Economist:
…Those
results recorded, Dr Burnham took saliva samples from all the students
and compared the testosterone levels assessed from those samples with
decisions made in the one-round game.As he describes in the Proceedings of the Royal Society, the
responders who rejected a low final offer had an average testosterone
level more than 50% higher than the average of those who accepted.
Five of the seven men with the highest testosterone levels in the study
rejected a $5 ultimate offer but only one of the 19 others made the
same decision.
What does this tell us? That physiological variables which are under biological (and ultimately genetic) control can affect the typical behavior a given individual exhibits, and, that that behavior can vary despite the same inputs across the population. There isn’t any one H. economicus, there are many different ways humans interact and their propensity for a particular strategy might be conditional upon biological parameters.
But
of course this doesn’t mean that a given individual practices a fixed
strategy even for the same inputs over time, just as strategies are
mixed throughout the population so they are often mixed over time for
any given individual. There is both population level and temporal
variation which must be taken into account here; the flat uniform world
of older economic imaginations were painted in shades of gray despite
the multi-colored nature of reality.
Additionally, as I have noted before,
even genetically close groups which are culturally distinct can exhibit
wildly different modal responses to these various experimental economic
games. This suggests that variation is not just extant on the
biological level (e.g., tracking testosterone variation within the
population), but also on the cultural level as the social parameters
shift and reshape the landscape of gene-environment interaction. In
other words, the behavioral economic biases can be likened to norms of
response of particular genotypes in various cultural environments.
Though the median value may shift, the distribution remains the same
(e.g., if a particular individual is high testosterone it is likely
that their response to the ultimatum game in one iteration will always
lay at one end of the distribution across cultures though the range and
shape of the distributions may vary quite a bit).
Reality is
complex. I’m alluding here to the interaction of genetic parameters
with various cultural norms. Additionally, the current work in relation
to various small scale societies where the "nominal" sums offered by
economists is non-trivial implies that analogical reasoning plays a
strong role in determining how the typical individual will respond. It
seems that most peoples don’t conceive of utility maximization, they
simply resort to analogies with transactions in their conventional life
which can be mapped onto the games they are being forced to play. So
there are innate parameters that result in a central tendency as well
as variation, but there are also cultural parameters which modulate the
range and constrain the scale, and, these often express themselves
general intelligence operating through analogical (as opposed to
deductive) reasoning. This turns rationality into a whole new beast altogether, not only is it bounded, it is nearly eviscerated as we understand it.
But why this variation in the first place?
First, I am implying that the conditional responses that an individual
gives has an expectation which is determined in large part by their
genetic inheritance. Imagine for example that the ratio of "aggressive"
to "passive" responses in a given game that an individual gives over
time as a ratio, and that this ratio is placed upon a graph. I suspect
that in many cases you would generate some sort of normal distribution
(you might have to transform it though). There would be a median modal
ratio; there would be those rare players who engage in "fixed"
strategies where they were invariant. In this way you can
re-conceptualize the behaviors documented in experimental economics as
continuous quantitative traits. We know from population genetic theory
that such traits have not been subject to powerful directional selection for long periods of time.
Otherwise, the underlying genetic variation would have been exhausted
as one behavioral morph comes to dominate the population of strategies
(the range of basal testosterone should be very
small and predominantly environmental/non-heritable). The reality of
polymorphism might imply that the "rationality landscape" (to borrow a
term) is characterized by multiple optima. Balancing selective forces
such as frequency dependence and environmental variation might also
result perpetuation of the mix. Layered on top of this evolutionary
biological level is the flux of cultural inputs which serves as the
background environment in which the predispositions develop into
lifelong typical strategies. We’ve come a long way from reciprocal altruism.
