Two experiments examined the role of compatibility of input and output (I-O) modality mappings in task switching. We define I-O modality compatibility in terms of similarity of stimulus modality and modality of response-related sensory consequences. Experiment 1 included switching between 2 compatible tasks (auditory-vocal vs. visual-manual) and between 2 incompatible tasks (auditory-manual vs. visual-vocal). The resulting switch costs were smaller in compatible tasks compared to incompatible tasks. Experiment 2 manipulated the response-stimulus interval (RSI) to examine the time course of the compatibility effect. The effect on switch costs was confirmed with short RSI, but the effect was diminished with long RSI. Together, the data suggest that task sets are modality specific. Reduced switch costs in compatible tasks may be due to special linkages between input and output modalities, whereas incompatible tasks increase cross-talk, presumably due to dissipating interference of correct and incorrect response modalities.

Input-output (I-O) modality compatibility refers to the similarity of stimulus modality and modality of response-related sensory consequences. A previous study found higher switch costs in task switching in I-O modality incompatible tasks (auditory-manual and visual-vocal) than in I-O modality compatible tasks (auditory-vocal and visual-manual). However, these tasks had spatially compatible S-R mappings, which implied dimensional overlap (DO). DO may have led to automatic activation of the corresponding compatible responses in the incorrect response modality, thus increasing interference effects. The present study was aimed to examine the influence of DO on I-O modality compatibility effects. In two experiments, we found that I-O modality compatibility affects task switching even in tasks without DO, which even tended to result in further increased modality influences. This finding suggests that I-O modality mappings affect response selection by affecting between-task cross-talk not on the level of specific response codes but on the level of modality-specific processing pathways.

In the current study, we set out to investigate language control, which is the process that minimizes cross-language interference, during bilingual language comprehension. According to current theories of bilingual language comprehension, language-switch costs, which are a marker for reactive language control, should be observed. However, a closer look at the literature shows that this is not always the case. Furthermore, little to no evidence for language-mixing costs, which are a marker for proactive language control, has been observed in the bilingual language comprehension literature. This is in line with current theories of bilingual language comprehension, as they do not explicitly account for proactive language control. In the current study, we further investigated these two markers of language control and found no evidence for comprehension-based language-switch costs in six experiments, even though other types of switch costs were observed with the exact same setup (i.e., task-switch costs, stimulus modality-switch costs, and production-based language-switch costs). Furthermore, only one out of three experiments showed comprehension-based language-mixing costs, providing the first tentative evidence for proactive language control during bilingual language comprehension. The implications of the absence and occurrence of these costs are discussed in terms of processing speed and parallel language activation.

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The present study was aimed at examining modality-specific influences in task switching. To this end, participants switched either between modality compatible tasks (auditory-vocal and visual-manual) or incompatible spatial discrimination tasks (auditory-manual and visual-vocal). In addition, auditory and visual stimuli were presented simultaneously (i.e., bimodally) in each trial, so that selective attention was required to process the task-relevant stimulus. The inclusion of bimodal stimuli enabled us to assess congruence effects as a converging measure of increased between-task interference. The tasks followed a pre-instructed sequence of double alternations (AABB), so that no explicit task cues were required. The results show that switching between two modality incompatible tasks increases both switch costs and congruence effects compared to switching between two modality compatible tasks. The finding of increased congruence effects in modality incompatible tasks supports our explanation in terms of ideomotor "backward" linkages between anticipated response effects and the stimuli that called for this response in the first place. According to this generalized ideomotor idea, the modality match between response effects and stimuli would prime selection of a response in the compatible modality. This priming would cause increased difficulties to ignore the competing stimulus and hence increases the congruence effect. Moreover, performance would be hindered when switching between modality incompatible tasks and facilitated when switching between modality compatible tasks.

Reduced congruency effects after a preceding incongruent trial suggest a conflict-monitoring process, which reactively triggers the recruitment of attentional control in subsequent trials. In the present study, we assessed this sequential modulation of crossmodal congruency effects separately in two different tasks. Participants performed a location judgment task and a numerical judgment task in a block-wise fashion in a modality-switching paradigm. Stimuli were presented simultaneously in two modalities and were either congruent or incongruent (e.g., left visual object, right sound) with each other. The target modality was indicated by a cue, so that the target modalities either repeated or switched in successive trials. For both tasks, the results indicated reduced congruency effects after an incongruent trial only for modality repetitions, but not for switches. This finding suggests that modality switches induce a shift in episodic context, which in turn leads to an attentional reset. This reset eliminates the sequential modulation of congruency effects.Keywords Conflict adaptation . Attentional state . Attentional reset . Modality switching Conflicts arise at many processing levels throughout perception and action, influencing the efficiency of our actions. A predominant idea of how our cognitive system deals with such conflicts refers to the existence of a conflict-monitoring system (Botvinick, Braver, Barch, Carter, & Cohen, 2001). Whenever conflict is detected and evaluated by this system, reactively adapted mechanisms of cognitive control increase processing selectivity (i.e., selective attention) so that conflict is reduced in subsequent processing episodes. For example, attentional biasing of task-relevant aspects is strengthened and task-irrelevant aspects have less influence, resulting in improved performance (Egner, 2007).Conflicts can be induced experimentally by providing incongruent stimulus information. For example, in the Stroop task (Stroop, 1935), participants are supposed to indicate the font color of written color words. In congruent trials, the word Bred^is also displayed in red, and Bred^is the correct answer, whereas in incongruent trials, the word Bred^might be displayed in blue (with Bblue^as the correct answer). Here, conflict arises between the automatically read color word and the to-be-named font color. Performance is usually better in congruent (no-conflict) than in incongruent (conflict) trials, termed the congruency effect.

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 switch either between two modality compatible tasks (auditory-vocal and visual-manual) or between two modality incompatible tasks (auditory-manual and visual-vocal). However, it remained unclear whether there is also a modality compatibility benefit when participants switch between a modality compatible and an incompatible task. To this end, in Experiment 1, we kept the same design as in earlier studies, so participants had to switch either between modality compatible or modality incompatible spatial discrimination tasks, but in Experiment 2A, participants switched at the response level (manual/vocal) while we kept the stimulus modality constant across tasks, and in Experiment 2B, they switched at the stimulus level (visual/auditory) while we kept the response modality constant across tasks. We found increased switch costs in modality incompatible tasks in Experiment 1, but no such a difference between modality compatible and incompatible tasks in Experiment 2A and 2B, supporting the idea that modality incompatible tasks increase crosstalk, due to the response-based priming of the competing task, but this crosstalk is reduced if the competing task involves either the same stimulus modality or the same response modality. We conclude that a significant impact of modality compatibility in task switching requires variability at the level of both stimulus and response modality.

Previous research suggested that specific pairings of stimulus and response modalities (visual-manual and auditory-vocal tasks) lead to better dual-task performance than other pairings (visual-vocal and auditory-manual tasks). In the present task-switching study, we further examined this modality compatibility effect and investigated the role of response modality by additionally studying oculomotor responses as an alternative to manual responses. Interestingly, the switch cost pattern revealed a much stronger modality compatibility effect for groups in which vocal and manual responses were combined as compared to a group involving vocal and oculomotor responses, where the modality compatibility effect was largely abolished. We suggest that in the vocal-manual response groups the modality compatibility effect is based on cross-talk of central processing codes due to preferred stimulus-response modality processing pathways, whereas the oculomotor response modality may be shielded against cross-talk due to the supra-modal functional importance of visual orientation.