Is it random or impulsive responding? The effect of working memory load on decision-making

Research has suggested individuals with limited working memory (WM) capacity make more impulsive choices than individuals without such limited capacity; however, the specificity of increased impulsivity has been challenged on the grounds that limited WM may lead to an increase in random responding rather than a true increase in impulsivity. Furthermore, whereas some previous research have demonstrated sex differences in decision-making, with males tending to make a higher proportion of impulsive decisions than females, the overall results in this area have been mixed. Thus, the current study specifically controlled for the impact of sex, a potential key issue within this area. In this study, 120 subjects (60 males) were randomly assigned to a WM load or control group and completed a decision-making task requiring rapid decisions. The task utilised three probability of loss conditions. The main findings centred on an interaction between sex and WM load, with males showing increased impulsive decision-making in WM load conditions, whereas females did not show a change in decision-making patterns under WM load. Results of this study support the claim that decreased WM capacity increases impulsive decision-making rather than random responding in men, whereas WM load was unrelated to risk-taking in women.