Modality compatibility in task switching depends on processing codes and task demands

Modality compatibility denotes the match between sensory stimulus modality and the sensory modality of the anticipated response effect (for example, vocal responses usually lead to auditory effects, so that auditory–vocal stimulus–response mappings are modality-compatible, whereas visual–vocal mappings are modality incompatible). In task switching studies, it has been found that switching between two modality-incompatible mappings (auditory-manual and visual–vocal) resulted in higher switch costs than switching between two modality-compatible mappings (auditory–vocal and visual-manual). This finding suggests that with modality-incompatible mappings, the anticipation of the effect of each response primes the stimulus modality linked to the competing task, creating task confusion. In Experiment 1, we examined whether modality-compatibility effects in task switching are increased by strengthening the auditory–vocal coupling using spatial-verbal stimuli relative to spatial-location stimuli. In Experiment 2, we aimed at achieving the same goal by requiring temporal stimulus discrimination relative to spatial stimulus localisation. Results suggest that both spatial-verbal stimuli and temporal discrimination can increase modality-specific task interference through a variation of the strength of anticipation in the response-effect coupling. This provides further support for modality specificity of cognitive control processes in task switching.

The interplay of crossmodal attentional preparation and modality compatibility in cued task switching

Two experiments examined the influence of preparation on modality compatibility effects in task switching. The term modality compatibility refers to the similarity between the stimulus modality and the modality of response-related sensory consequences. Previous research showed evidence for modality compatibility benefits in task switching when participants switched either between two modality compatible tasks (auditory-vocal and visual-manual) or between two modality incompatible tasks (auditory-manual and visual-vocal). In this study, we investigated the influence of active preparation on modality compatibility effects in task switching. To this end, in Experiment 1, we introduced unimodal modality cues, whereas in Experiment 2, bimodal abstract cues were used. In both experiments, the cue-stimulus interval (CSI) was manipulated while holding the response-stimulus interval (RSI) constant. In both experiments, we found not only decreased switch costs with long CSI but also the elimination of the residual switch costs. More importantly, this preparation effect did not modulate the modality compatibility effect in task switching. To account for this data pattern, we assume that cue-based preparation of switches by modality mappings was highly effective and produced no residual reaction time (RT) costs with long CSI.