When Response Selection Becomes Gambling: Post-error Slowing and Speeding in Self-paced Colour Discrimination Tasks

People tend to slow down after committing an error in many tasks. However, some studies failed to observe such post-error slowing. Furthermore, recent work found speeding after another type of sub-optimal outcomes: people often speed up after losses in gambling situations. What features determine whether people slow down or speed up after sub-optimal outcomes (error vs. loss)? To answer this question, we focused on the role of task characteristics and control over the outcome, by making a task where we previously observed post-error slowing more like tasks where we previously observed post-loss speeding. First, we made a color-discrimination task completely self-paced (Experiment 1A) and added reward/punishment (Experiment 1B). In both experiments, post-error slowing was observed, without modulation by reward/punishment. We then manipulated task difficulty to investigate the influence of control over the outcome. Consistent with our predictions, control over the outcome modulated post-error adjustments, as participants slowed down after controllable errors, but sped up after uncontrollable errors (Experiment 3). Importantly, this effect was global as post-error speeding was observed when controllable and ’uncontrollable’ errors were intermixed (Experiment 2), suggesting an influence of overall task context. Thus, responses to sub-optimal outcomes might depend on the control over the outcome.