Social Decision-making

Imagine walking down Broadway in New York City and seeing two enormous billboards, one showing an image of a table overflowing with chocolates and the other depicting a highly attractive member of the opposite sex. Where do you look? How does this depend on how hungry you are or whether you’ve been on a date recently? How do you weigh the costs and benefits of looking at either billboard? How does this depend on who’s walking down the street with you? These questions go straight to the heart of addressing the rather simple question of how your brain chooses where to look.

To begin to address these questions, we are probing the abstract representation of behavioral value for visual orienting. In this project, led by post-doctoral fellow Robert Deaner, we begin by measuring the value of social images for visual orienting. Monkeys are offered the choice looking at one of two targets. Looking at either target results in a squirt of fruit juice, but the amount of juice associated with each target varies throughout the day. Crucially, looking at one of the targets is also consistently followed by the brief appearance of a social image at that location, usually a familiar monkey’s face. By using psychophysical techniques, we are able to quantify, in terms of fruit juice, the motivational value of seeing particular types of images. In other words, the monkeys’ behavior allows us to assess precisely how much juice the monkey will give up to see particular individuals. In fact, data collected so far indicate that monkeys will consistently give up juice to look at some monkeys, but must be “overpaid” to look at others. To explore the mechanisms underlying this behavior, we have begun recording from neurons in parietal cortex while monkeys perform this social choice task. One of our primary questions is whether neurons show similar modulation when a monkey is anticipating viewing a preferred social image and when anticipating a large juice reward. If so, this would suggest that parietal cortex encodes an abstract representation of behavioral utility that is used to decide where to look.