Figure 1.

Experimental Design

Following a familiarization phase, participants were shown four pictures on each trial and asked to choose one. Both familiarized and novel pictures were presented at randomized locations that changed on each trial. Each picture was repeated for an average of 20 trials and then replaced. Participants were informed that each picture had been assigned a unique probability of winning £1 that would not change as long as that picture was repeated. They were given feedback at the end of each trial indicating whether they had won or received nothing.