On the behavioral level, we found several interesting patterns. Results demonstrated that both groups effectively modified their strategy based on outcomes in the first block of trials. However, while the placebo group started off cautiously during the first block and then increased the number of risky choices to an optimal level during the remaining blocks, the alcohol group exhibited the opposite strategy. Initially, this group made more risky choices than the placebo group but adopted a safer strategy during the remaining two blocks, arguably after realizing that the initial strategy was not optimal. However, in contrast to the placebo group, the alcohol group did not approach the optimal balance of 64 pumps, but kept on using a less effective strategy. This finding might explain the heterogeneity of results from previous studies, some of whom failed to observe increases in risk-taking after alcohol consumption or even reported decreases (Breslin et al. 1999; Ortner et al. 2003). Analyses based on choices across the entire task may have obscured group differences in strategy changes during the tasks in those studies.
