Laurie Santos has been experimenting with “monkeynomics”. She has taught a group of monkeys to use money – metal discs – to pay for treats then after straightforward “purchases” of treats, one grape for one disc, become routine she offers two scenarios in each of which the monkeys can decide between two options. These are scenarios in which human decision making has been analysed and found to follow a set pattern.

In the first scenario, the monkeys have a choice between two people, A and B, each of whom offers one grape. A always adds one grape when a money offers a coin, making two. B gives just the one grape 50% of the time, and 50% of the time adds two more, making three. This is a situation of possible gain. But rationally, especially with the opportunity to make multiple purchases, both average out at 2 grapes so it makes little difference which you choose. However, humans are biased towards one of these options; for our purposes it doesn’t matter which.

The second scenario is one in which both A and B each offers three grapes. A always takes one away before handing over two, B gives all three half the time, and 50% of the time takes two away, leaving one. This is functionally identical to the first scenario but feels different. A always gives 2 grapes, B might give 1 or 3, but in the first scenario it feels like possible gain and in the second it feels like possible loss. This time humans display the opposite bias.

This shows that human decision making is at least partly irrational. If we were rational, even if we displayed a bias toward one or other of A and B, we would display the same bias in both scenarios.

Monkeys behave in exactly the same way. The biases are the same in each scenario and, just as with humans, the bias changes between the two. The irrationality is the same, something that is more revealing than a similarity in rational decision making – which could be attributed to the underlying rationality of the decision.

More work needs to be done, but this at least raises the possibility that even decision making of this sort, that affects our deepest economic behaviour, could be hard-wired in us. Our common ancestor with the monkeys in the experiments lived something like 35 million years ago.

I recently argued with Chris Dillow about whether status is inherent (following an initial post by Tim Worstall); the evidence seems to show it is. Taking an evolutionary perspective, concern for status can be seen in most, perhaps all, of our part of the tree. These experiments in economic behaviour show how subtle and far-reaching inherited behaviour might be. That’s inconvenient for utopian political beliefs, because these generally rely on the possibility that human behaviour could be changed.

An evolutionary perspective can cast light on other political debates, especially when the fallacies of creationism are unpicked. That’s the subject for a later post.

UPDATE: An afterthought. It’s occurred to me that rather than being the only species on his planet to develop an advanced intelligence, we are merely the first to do so. These might seem equivalent but the former is generally taken to mean we’re the only species capable of developing like this, that there’s a category difference between us and other species (often this is a religious view but it’s not exclusively so), and that’s what I’m contradicting.

There’s a measure of a developed species, perhaps, that concerns not its own ascent to intelligence, but whether or not it permits any other species to develop to an advanced stage. I wouldn’t bet that we’ll pass that particular test.