Hitchhiking actions: Erroneous saccade co-execution is independent of stimulus-response translation ease

Abstract

Abstract Recent multiple action control studies have demonstrated difficulties with single-action (vs. dual-action) execution when accompanied by the requirement to inhibit a prepotent additional response. Such a dual-action performance benefit is typically characterized by frequent erroneous co-executions of the currently unwarranted response. Here, we investigated whether the frequency of inhibitory failures is affected by the ease of stimulus-response (S-R) translation. Participants switched between executing a single saccade, a single manual button press, and a saccadic-manual dual action on a trial-by-trial basis. We measured inhibitory failures in single action trials (e.g., saccades executed in single manual trials). Importantly, we employed three different stimulus modes that varied in S-R translation ease (peripheral square > central arrow > central shape). This hierarchy was reflected by increasing RT levels. Critically, however, the frequency of saccadic inhibitory failures was not affected by S-R translation ease. Our results rule out explanations related to capacity conflicts (between inhibitory control and S-R translation demands) as well as accounts related to the time available for the completion of inhibitory processes. Instead, the findings suggest an “action hitchhiker effect” based on enhanced activation of the oculomotor system, eventually yielding the execution of unwarranted, holistic dual-action compounds.