The role of source memory in gambling task decision making

Abstract

The role of memory in the Iowa Gambling Task (IGT) was tested in two experiments that dissociated item memory (memory for losses obtained) from source memory (the deck that produced a given loss). In Experiment 1, participants observed 75 choices that had been made by controls or patients in previous research, followed by memory tests, and then 25 active choices from the participant. In Experiment 2, participants made choices for 75 trials, performed the memory tests, and then made 25 final choices. The data show that item and source memory can diverge within the IGT, and that source memory makes a significant contribution to IGT performance.

Keywords:

• Iowa Gambling Task
• Source memory
• Item memory
• Decision making
• Executive function

Notes

¹Even though our subject population consisted of young, healthy adults, the number of good choices was relatively low for a sizable number of our participants. This could be due in part to the fact that they were learning passively from the first 75 trials rather than actively making choices. However, it is not unusual to find, even with active decision making throughout the task, that a sizable number of neurologically intact participants continue to make disadvantageous choices throughout the IGT. See Dunn et al. (2006) for a review.

²The data reported are from the binormal model using maximum likelihood estimation. We also conducted the analyses using a nonparametric model and obtained parallel results, so our findings do not appear to be contingent on the specific signal detection model employed.

³We also repeated the regression analysis using performance on the earlier trial blocks as the dependent variable. Memory was predictive of performance only in trial block 4. However, the present data cannot address whether earlier assessment of memory would predict earlier choice behavior.