Mouse cursor movements in cognitive bias tasks reveal underlying processing differences

Biases are prevalent in human Judgement and Decision Making (JDM). Previous research has suggested that some biases might share common underlying causes and can be accounted for under dual process theories in which fast and error-prone System 1 drives erroneous behaviour. Here, we use an online paradigm to investigate similarities and differences in behaviour across three commonly studied cognitive bias phenomena: Cognitive Reflection Test (CRT), Gambler’s Fallacy (GF) and Conjunction Fallacy (CF). These are all thought to be underpinned by the representativeness heuristic emerging during biased System 1 processing. Critically, we examine both summative performance metrics as well as process tracing measures derived from mouse cursor movements and growth curve analysis (GCA). Summative performance in these tasks was broadly in line with previous studies and we replicated correlations in accuracy between tasks (CRT vs. CF and CRT vs. GF). However, we found key differences in our GCA of mouse trajectories. Specifically, in the CRT and the CF tasks participants tended to choose the incorrect option more quickly relative to the correct option, as might be expected. However, the opposite tendency was observed for GF – people tended to take longer to choose the wrong answer. We also found evidence from the mouse movement analyses for between-task differences in the extent to which participants were tempted by the option they did not choose. These findings challenge prominent dual process accounts of JDM and highlight the potential of process tracing (and in particular mouse movement analyses) for revealing insights into cognitive processes.