To give your child an incentive to take out the garbage, you might offer to buy her a treat, or you might threaten to withhold her regular allowance. Does the child respond the same way to reward as it does to avoiding punishment? Psychologists have evidence from certain kinds of behavioral experiments to believe that avoiding punishment is itself a reward. In a new study published online in the open-access journal PLoS Biology , Hackjin Kim, Shinsuke Shimojo, and John
Sixteen people participated in the study, during which they could either lose or win one dollar in an instrumental choice task. During the experimental trials, participants selected one of two fractal images presented on a screen. After a fractal was chosen, it became brighter, and four seconds later the participant got one of four types of feedback: reward (a picture of a dollar bill and the message, You win!), negative outcome (same image, with the text, You lost!), neutral (a scrambled bill with the text, No change), or nothing (a blank screen). During reward trials, the choice led to a high or low probability of reward (earning a dollar); during avoidance trials, the choice led to a high or low probability of avoiding a negative outcome (losing a dollar).
Over time, participants learned to choose fractals associated with a greater probability of reward and a lower probability of a negative outcome. And, as predicted, the medial OFC showed a higher response when participants chose an option that resulted in not losing the dollar or in winning it. Conversely, when participants
Avoiding negative outcomes and receiving rewards amount to the same thing for the brain: achieving a goal. Reward serves as an external signal that reinforces behavior associated with a positive outcome, Kim et al. explain, and punishment amounts to an intrinsic reward signal that reinforces actions linked to avoiding bad outcomes. With fMRI evidence connecting avoidance and reward circuits, researchers can now determine which neuron populations within the OFC contribute to the avoidance "reward response"and perhaps shed light on the neurobiological roots of pathological risk-seeking behavior.
Citation: Kim H, Shimojo S,
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