Elliot Ludvig, University of Warwick
When it comes to gambling, people really are bird brains - a recent study has shown that people and pigeons assess risk in exactly the same way. Elliot Ludvig from the University of Warwick spoke to Ginny Smith about the findings...
Elliot - So, we were particularly interested in the ways that both people and pigeons learn about rewards and risks from their own experiences. So, when we were looking at when they’re learning from experience, we thought that we would take away the verbal component and the calculating ability of humans, and look at whether when we have them learn from a series of experiences. We might actually see similarities that you don't tend to see when you ask people much more explicitly about what they're actually going to do.
Ginny - So, how did you do that?
Elliot - So, what we did is we try to design an experiment that had the same sorts of structure for both the people and the birds. So for the people, we had them play a little computer game where they sat down at a screen and they clicked at various different coloured doors which hidden behind the doors were different rewards. And it would be revealed when they opened it. So, the only experience they had was when they clicked on the door, what was behind it. We didn’t tell them anything about what to expect, what the odds were, what they could possibly get. We did something structurally similar for the pigeons. So we had the pigeons play, what was more similar to them or more like a forging game for them. So, what they did is they went into a room and we had various objects and hidden behind the different coloured objects were different amounts of food, different little bowls containing food. The pigeons similarly had to go into this environment and from their own experience, find out what was hidden behind the different objects and then choose between them. To assess their gambling tendencies and their risk seeking, what we did is we had both the people and the pigeons pick between a safe option, which always gave them the same amount of points in the case of humans or food in the case of the birds, against the risky option, which gave them a 50/50 chance of either getting more, a bigger reward or a smaller reward. And so, that's how we tried to design the experiment so that both the birds and the people only had the same same types of experiences. So, we can actually make them a little bit more equivalent and look at whether both the people and the birds learned in similar ways and then assess the risk in similar ways and then gambled in similar ways.
Ginny - And what did you find? Did you find that people were better at learning than pigeons? That's kind of what I would imagine.
Elliot - We thought so too, but we didn’t find that. We found that both of them, in these situations, when you take away the verbal instructions and you take away the descriptions that people tend to rely on and all you give them is the raw experience from them to draw on, both species learned fairly similarly in terms of speed and their choices were actually remarkably similar in that, we had them play various variations of the game, some were higher stakes, some were lower stakes. And the main thing we found was that in the higher stakes games when they learn from experience, both the people and the pigeons gambled about 35% more often than they did in the lower stakes games when they were learning from their experience this way.
Ginny - So, you're more likely to take a risk on getting a worse chance if the reward is bigger whereas, if it’s only a little bit of a reward, you're not going to take much risk. That kind of makes sense.
Elliot - That's right. So, that's what they did. When they had the potential, of getting a higher reward they gambled. The way it was set up was that the safe option was always about equal to the average of the outcomes on the – so the safe option was better for the higher rewards than for the lower rewards. So, they were also foregoing something better to get at the high rewards and yet nonetheless, they were still willing to gamble in those situations.
Ginny - So rationally, you should’ve gone for the safe option and yet, we take a risk when there might be a higher reward. What can that tell us about the evolution of our brains that both we and pigeons who we haven't shared a common ancestor with for a really long time, make the same decision?
Elliot - So, there's a couple of things it might suggest. One, is the possibility is that this is really primitive in a sense that this is something that we share with many other animals that existed 300 million years ago, precursor ancestor to both the pigeons and us. And that our behaviour reflects that. So, that's one possibility. The other possibility is that maybe we share common evolutionary pressures and that the acts that we have to undergo and the things we need to do in order to avoid predators or gather food are sufficiently similar, that these sorts of basic biases are really, really effective. Learning in this way and behaving in this way is something that's a very useful thing and therefore, many, many species have evolved it multiple times. We can't really distinguish those based on what we have found, but there's two different ways that you might want to think about the similarities.
This interview was very interesting and got me thinking... In normal pigeon experience the food supply probably isn't unpredictable in the same way as a deliberately randomized experiment. So any experience that has had a large payoff in the past might well be worth repeating so that the bird can learn how to predict or even influence the (chances of) payoff in the future. It reminds me of some roulette players I once saw who were acting out various superstitions during the game, presumably hoping to increase their chances of success. RMG, Sun, 14th Sep 2014