Poverty, mental health and rhesus monkeys

Today I came across a very interesting paper titled “Values Encoded in orbitofrontal cortex are causally related to economic choices” by Ballesta, Shi, Conen and Padua-Schioppa. I haven’t read and analyzed the paper fully, partly because of the many statistical tools that I will have to learn to assess it carefully. However, I did manage to read some important bits, and it set me thinking about how it directly applies to so many of us in our daily lives.

In this paper, the researchers claim that our subjective values of things are hard-coded in our orbitofrontal cortices. That is just a fancy way of saying that if we like burgers more than fries, this information is stored in a part of the brain that lies directly above your eyes. Hence, every time you’re offered a choice between burgers and fries, that part of your brain implores you to choose burgers.


The following experiment was done on rhesus monkeys. They were given a choice between 2 drops of grape juice and 6 drops of peppermint tea. Depending upon their surjective preferences (as coded in their orbitofrontal cortices), they would prefer one or the other. For example, let us assume that a monkey named Tim would mostly choose the 2 drops of grape juice over peppermint tea. How exactly is Tim offered these choices?

Tim is first shown a picture of 2 drops of grape juice. Then after a 1 second delay, he is shown a picture of 6 drops of peppermint tea. He is then asked to choose amongst the two images. He consistently chooses the grape juice.

However, suppose a current of 100 \mu A is passed through his orbitofrontal cortex every time he is shown the grape juice image. The passage of this current causes Tim to start choosing peppermint tea slightly more often than before. Note that Tim does not have a clear preference for peppermint tea as such. It is just that his choices become more randomized. Why does this happen? The authors of the paper think that the current interferes with the working of the orbitofrontal cortex, which was initially asking it to consistently choose the grape juice.

AB means that A is being offered first, and B is being offered second. StimON means that current is passed during the first offer.

Depression and poverty

If you’ve been depressed before, you can surely empathize with this. Let us suppose that in a happy and stable state of mind, you’d always prefer the color red over blue. Given the choice between two t-shirts of those colors, you’d consistently choose the red one. However, once that depression hits, you don’t really care anymore. You’d start choosing the blue one more often than before because they’re all the same, and it doesn’t matter. Our brain just refuses to do the computation that leads us to conclude that we prefer red over blue (yes, even choices are a result of mental computation). And the absence of computation leads to random choice.

What about poverty? Imagine that poverty causes a small current to run though your orbitofrontal cortex. This causes your brain’s computational capacities to plummet, leading you to make arbitary choices, or perhaps choices that are dictated by short term thinking (obviously short term thinking requires less computation than long term thinking). Say at the end of a hard day’s labor, you have $100 in your pocket. If you save $50 every day for a year, you will have saved enough money to accumulate interest, perhaps help you tide over bad times. But c’mon. You’re incapable of that computation. Your orbitofrontal cortex is screaming at you to save some money at least. You’ve been through terrible times, and if you’d saved in the past, you’d have been so much better off. You know that you should save money. You’ve definitely been burned enough times to know that. But you cannot hear your brain screaming over the current. You’d rather go to the bar right now and drink it all up. Tomorrow is another day.

What about self-destructive behaviour? What if the lack of will power is basically the lack of computational capabilites? This is perhaps getting into speculative territory. But these are burning questions that can be answered using a similar experimental evidence as described above.

The analysis above is different from the paper in one significant aspect: in the case of depression and poverty, there’s a current that is always running through the orbitofrontal cortex. Hence, our brain, that is now incapable of computing and hence making a good choice, now makes a random choice. However, in the experiment, the current is running through Tim’s brain only when the first choice is being shown. In effect, the current interferes with Tim’s ability to register or analyze the first choice properly. Hence, he starts choosing the second choice, which he can at least perceive properly (even though he may not like the second choice per se). If current through the orbitofrontal cortex does indeed decrease computational capabilities, then this current is causing Tim to not be able to carry out the computation to register the first choice, hence leading it to go for the second choice that it has registered better.

It would be interesting to see an experiment in which Tim has a clear preference for choice A, and a current is running through his brain when both choices are presented. Will this randomize his choices between A and B? That would then provide supporting evidence for my brain current theory of depression and poverty.


  1. Values Encoded in orbitofrontal cortex are causally related to economic choices” by Ballesta, Shi, Conen and Padua-Schioppa

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Graduate student

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