Post by Stephanie Williams

What's the science?

We know from animal studies that reward-related cues like noises (chimes) or visual signals (flashing lights) can influence animals to make risky decisions. It is still unknown if reward-related cues can influence humans in a similar way. It is also unclear how the cues would exert their effects on decision making. This week in the Journal of Neuroscience, Cherkasova and colleagues assessed the effects of reward-associated sensory cues on the promotion of risky decisions in humans.

How did they do it?

The authors randomized 131 human subjects to play two computerized games, either with or without visual (i.e. stacks of bills or coins) and auditory (casino chiming noises) cues, to test whether these cues affected decision making. The first game, the Iowa Gambling Task (IGT), consisted of four decks of cards, and the participant’s goal was to win as much money as possible by selecting cards from the decks. Some decks were more advantageous than others, and each time the participant selected a card, they either won or lost money. To win the maximum amount of money, participants should have chosen cards from the two of the four decks that had low risk/low reward cards (no big wins, but no big losses either). In the second game, the Vancouver Gambling Task (VGT), participants had to choose between a low chance of winning a larger amount of money, and a higher chance of winning a smaller amount of money. Participants were repeatedly presented with various pairs of potential winnings. The researchers used the participant’s choices in this task to create a model of a participants' willingness to take risks.

The authors tracked several physiological measurements including eye movements and pupil dilation, which is related to arousal. Eye tracking data was analyzed to measure time spent looking at probability information (participants were shown pie charts representing probabilities of winning during the VGT task). Pupil size was analyzed from the VGT to see whether the auditory and visual effects were related to pupil dilation, and whether dilation was related with riskier choices.