Stimulus material for the manuscript "How global and local task context influence task-set inertia in dual tasking"

Cognitive control must be flexibly adjusted when task demands change, yet task-set inertia can impair performance by keeping previously relevant task sets active. This study investigated task-set inertia using a hybrid psychological refractory period (PRP) paradigm, combining a visual-vocal short-term memory task with an auditory-manual reaction time (RT) task. We manipulated the stimulus-onset asynchrony (SOA: 100 vs. 1,000 ms) and the relevance of the visual-vocal short-term memory task (task load: report the stimulus vs. ignore the stimulus). In Experiment 1, task load varied unpredictably (trial-by-trial) or predictably (in blocks). In Experiment 2, we implemented blocks with majority report or majority ignore trials (75% respectively) to examine how global task context influences task-set inertia. Results showed the expected SOA effect in report conditions, with worse performance in the auditory-manual RT task at short compared to long SOA. This SOA effect suggests a processing bottleneck between short-term memory consolidation of the visual target and response selection for the auditory target. The SOA effect persisted (but was smaller) in ignore trials, indicating task-set inertia. This residual SOA effect was modulated by the previous trials’ task load, with a larger SOA effect when the previous trial was a report compared to an ignore trial. Additionally, the residual SOA effect almost disappeared in predictable ignore blocks and was modulated by the proportion manipulation, showing a larger SOA effect in majority report blocks. These findings show that both global and local task context influence task-set inertia, demonstrating that task sets are context-sensitive and show involuntary persistence