Reward and Punishment
Next, we delve deeper into the brain to uncover punishment, reward, and motivation with Dr. Hanneke den Ouden at Radboud University, the Netherlands.
Hanneke - So, I was watching the football match last night on Dutch and so, the Dutch were playing Costa Rica and when the Dutch finally won the penalty series, you could see them all kind of jumping around and then when you looked at the Costa Ricans, they were just like rooted to the spot. They were just not moving at all. That really nicely reflects that link between kind of good stuff and kind of being really active, and punishments, and being really inhibited, like being really like stopping your behaviour. And so, we actually study this process. We study how rewards on one and punishments on the other hand really can influence your behaviour in a way that you might not be aware of, unlike probably in the football match where they probably are quite aware of what is happening. So, I'll give you an analogy of the experimental design that we actually do in the lab. So, suppose that you're thinking about buying a house and you're going for a viewing. On the wall in the house, there's a picture and this picture happens to be the same picture as the one that was hung up in the ice cream shop in the neighbourhood where you grew up. So, you probably have a very, very strong positive feeling when you see this picture. You might not actually be aware of this. And so, you might actually end up being more likely to buy this house because this picture is hanging there. Even if you know that the owner is going to take the picture with him when they're leaving, the opposite actually might happen. Maybe there's a picture hanging on the wall that used to hang in the headmaster's office where you had to write your lines when you've been naughty in class. And so, you have a very kind of negative association with this picture. And so, you might actually not buy the house. You might really not be aware of this influence, that picture has on you. Again, the picture is going to go away with the owner, so it doesn't affect the value or shouldn't affect the value of the house to you. But instead, it does actually influence you. And so, what we do is we kind of create a very similar situation in the lab where we actually show people pictures and in some cases, have them follow by a very nice sip of juice that we've given thirsty people and we show them other pictures and then we give them a sip of really nasty magnesium sulphate solution. And so, what we then do is we see how, when we show these pictures in the background of another game that people are playing when really, the picture shouldn't be affecting their behaviour, whether it actually affects their behaviour. And so, what we see is that when you show people the kind of nasty picture in the background, people are really inhibited in their responding whereas if you show people the nice picture, the one that's associated with the nice fruit juice, people actually activate their responding, so they get really active.
Hannah - Are there different types genes or chemicals in the brain that somehow regulates how we can respond to these positive or negative kind of pictures or associations?
Hanneke - Yes, so that's exactly what we're interested in studying. What we've actually seen is that there is this one neurochemical called serotonin which seems to be particularly associated with how people respond to negative events, to punishments. And so, when you actually lower people's levels of serotonin, they actually become - in this case - more likely to buy the house. So, they're sort of disinhibited in their responding to an aversive stimulus.
Hannah - And serotonin is usually associated with - so people for example who may have clinical depression would be given serotonin selective reuptake inhibitors which would increase their amount of serotonin to try and make them happier. But your results are also showing that serotonin has this other flip side.
Hanneke - This is exactly kind of the confusion that drove our research because on the one hand, people who are depressed and who seem to be more sensitive to punishments have lower levels of serotonin or we think that they might do. On the other hand, people who have impulse control disorders, people who basically seem to not take into account that their behaviour is going to be bad consequences. So, they seem to be less sensitive to aversive outcomes. That was really confusing. How can two disorders that are both associated with low levels of serotonin on the one hand seem to be more sensitive to punishments and on the other hand less sensitive to punishment. And so, in another study, we looked at genetic differences in people's serotonin system and one of the serotonin genes. And actually, sure that people respond differently to punishment, depending on which version of this gene. Some people became really very much more sensitive to punishment whereas other people, when they just received a punishment, they just don't seem to mind quite as much and they just kind of carry on what they were doing for regardless.
Hannah - Do you think we'll ever get to the stage where we could maybe take some of Hitler's DNA for example and have a look at his serotonin genes and then find out whether he might be affected by this kind of punishment paradox?
Hanneke - So, that's an interesting question. There are definitely some kind of predispositions that we have and we have particular versions of the gene. But actually, for this specific gene, it's already known that the effects of the gene also very much depend on what's happened to you in your life. Life events, something really bad happening to you might for example cause your serotonin levels perhaps to drop. This is again quite speculative and that might actually interact with the genes that you have. And so, it will be very difficult to say and I don't think we'll ever get to a point where you can say, "Well, this is what somebody's genes are and therefore, they are this kind of person" but it really depends on the kind of environment that you're in which interacts and all kind of come together in your brain to make you act the way you do.
Hannah - Thanks to Hanneke de Ouden who researches reward and punishment at Radboud University, Netherlands.