The role of implicit and explicit learning in the Iowa Gambling Task: An investigation into individual differences in the decision making process.

Abstract

We presented a sample (37) of Edinburgh University students with a computerised version of the Iowa Gambling Task (IGT), together with two tasks designed to assess implicit (Serial Reaction Time Task) and explicit (Rey Auditory Verbal Learning Test) learning, in order to assess the role of implicit and explicit learning in the decision making process. We predicted that participants who performed better at the SRTT (implicit learning test) would perform better on the first stage of the IGT when no explicit knowledge of reward/punishments was available to them and participants who performed better at the RAVLT (explicit learning test) would perform better in the second stage of the IGT when they had some explicit knowledge of reward/punishment outcomes. We found no correlations between SRTT and IGT performance and only mild correlations between certain RAVLT trials (post-interference and delay) and performance on block 4 of the IGT. Results indicated that IGT performance might not be predicted by individual ability to implicitly or explicitly learn but might instead rely on covert emotion based somatic markers to guide decision making (Bechara et al., 1994). However, there was some suggestion that interference susceptibility and long term memory ability might play a more important role in predicting latter IGT performance than previous research has suggested. Alternatively, based on previous findings, it is possible that limitations in the learning tests used and the way they were administered might have prevented results from reaching a significant effect. Furthermore, without detailed future investigation involving tasks that specifically tax learning mechanisms involved in the IGT, we remain a distance away from fully establishing the role of implicit and explicit functioning in the decision making process