Researchers can examine activity in the brain by using electroencephalography (EEG). The authors of this study used EEG to assess responses to rewards. They asked participants to play a slot machine for 228 trials. The outcome of each trial could be a loss, a near miss, or a win. Participants had their EEG readings taken throughout their slot machine play. The researchers found that there were differences in brain activity in response to the three types of outcomes. Stimulus-preceding negativity (SPN) was larger when participants were anticipating a potential win. During the early stage of processing an outcome, the reward positivity (RewP) was larger for wins than near misses. RewP responses were larger in younger participants. Late Outcome Evaluation (LPP) was larger for wins and near misses than losses. Participants were quicker to initiate the next trial after near misses in comparison to wins and losses.
