Response interference in touch, vision, and crossmodally: beyond the spatial dimension

Creating a network of importance: The particular effects of self-relevance on stimulus processing

Several factors guide our attention and the way we process our surroundings. In that regard, there is an ongoing debate about the way we are influenced by stimuli that have a particular self-relevance for us. Recent findings suggest that self-relevance does not always capture our attention automatically. Instead, an interpretation of the literature might be that self-relevance serves as an associative advantage facilitating the integration of relevant stimuli into the self-concept. We compared the effect of self-relevant stimuli with the effect of negative stimuli in three tasks measuring different aspects of cognitive processing. We found a first dissociation suggesting that negative valence attracts attention while self-relevance does not, a second dissociation suggesting that self-relevance influences stimulus processing beyond attention-grabbing mechanisms and in the form of an "associative glue," while negative valence does not, and, last but not least, a third dissociation suggesting that self-relevance influences stimulus processing at a later stage than negative valence does.

Identity-Based Crossmodal Negative Priming: Aftereffects of Ignoring in One Sensory Modality on Responding to Another Sensory Modality

Negative Priming (NP) refers to the phenomenon that responses towards previously ignored stimuli, as compared to new stimuli, are impaired. That is, NP is reflected in the performance on the probe display of a prime-probe sequence. NP is established in vision, audition and touch. In the current study, we presented participants with auditory, visual, and tactile manifestations of the same temporal patterns in order to measure NP across the senses. On each trial, the sensory modality shifted from the prime to the probe. Each prime and probe display consisted of a target and a distractor stimulus, presented to the same sensory modality. On some trials, the prime distractor repeated as probe target (ignored-repetition trials), on other trials the probe stimuli had not been involved in the prime display (control trials). We observed NP between audition and touch (Experiment 1) and between vision and audition (Experiment 2). These findings indicate that the processes underpinning NP can operate at an amodal, postperceptual level.

Interference of irrelevant information in multisensory selection depends on attentional set

In the multisensory world in which we live, certain objects and events are of more relevance than others. In the laboratory, this broadly equates to the distinction between targets and distractors. In selection situations like the flanker task, the evidence suggests that the processing of multisensory distractors is influenced by attention. Here, multisensory distractor processing was investigated by modulating attentional set in three experiments in a flanker interference task, in which the targets were unisensory while the distractors were multisensory. Attentional set was modulated by making the target modality either predictable or unpredictable (Experiments 1 vs. 2, respectively). In Experiment 3, this manipulation was implemented on a within-experiment basis. Furthermore, the third experiment compared audiovisual distractors (used in all experiments) with distractors with one feature in a neutral modality (i.e., touch), that never appeared as the target modality in the flanker task. The results demonstrate that there was no interference from the response-compatible crossmodal distractor feature when the target modality was predictable (i.e., blocked). However, when the modality was varied on a trial-by-trial basis, this crossmodal feature significantly influenced information processing. By contrast, a multisensory distractor with a neutral crossmodal feature never influenced behavior. This finding suggests that the processing of multisensory distractors depends on attentional set. When the target modality varies randomly, participants include features from both modalities in their attentional set and the irrelevant crossmodal feature, now part of the set, influences information processing. In contrast, interference from the crossmodal distractor feature does not occur when it is not part of the attentional set.

Crossmodal attentional control sets between vision and audition

The interplay between top-down and bottom-up factors in attentional selection has been a topic of extensive research and controversy amongst scientists over the past two decades. According to the influential contingent capture hypothesis, a visual stimulus needs to match the feature(s) implemented into the current attentional control sets in order to be automatically selected. Recently, however, evidence has been presented that attentional control sets affect not only visual but also crossmodal selection. The aim of the present study was therefore to establish contingent capture as a general principle of multisensory selection. A non-spatial interference task with bimodal (visual and auditory) distractors and bimodal targets was used. The target and the distractors were presented in close temporal succession. In order to perform the task correctly, the participants only had to process a predefined target feature in either of the two modalities (e.g., colour when vision was the primary modality). Note that the additional crossmodal stimulation (e.g., a specific sound when hearing was the secondary modality) was not relevant for the selection of the correct response. Nevertheless, larger interference effects were observed when the distractor matched both the stimulus of the primary as well as the secondary modality and this pattern was even stronger if vision was the primary modality than if audition was the primary modality. These results are therefore in line with the crossmodal contingent capture hypothesis. Both visual and auditory early processing seem to be affected by top-down control sets even beyond the spatial dimension.

Multisensory top-down sets: Evidence for contingent crossmodal capture

Numerous studies that have investigated visual selective attention have demonstrated that a salient but task-irrelevant stimulus can involuntarily capture a participant's attention. Over the years, a lively debate has erupted concerning the impact of contingent top-down control settings on such stimulus-driven attentional capture. In the research reported here, we investigated whether top-down sets would also affect participants' performance in a multisensory task setting. A nonspatial compatibility task was used, in which the target and the distractor were always presented sequentially from the same spatial location. We manipulated target-distractor similarity by varying the visual and tactile features of the stimuli. Participants always responded to the visual target features (color); the tactile features were incorporated into the participants' top-down set only when the experimental context allowed for the tactile feature to be used in order to discriminate the target from the distractor. Larger compatibility effects after bimodal distractors were observed only when the participants were searching for a bimodal target and when tactile information was useful. Taken together, these results provide the first demonstration of nonspatial contingent crossmodal capture.

Functional characteristics of control adaptation in intermodal sensory processing

The present work investigated functional characteristics of control adjustments in intermodal sensory processing. Subjects performed an interference task that involved simultaneously presented visual and auditory stimuli which were either congruent or incongruent with respect to their response mappings. In two experiments, trial-by-trial sequential congruency effects were analysed for specific conditions that allowed ruling out "non-executive" contributions of stimulus or response priming to the respective RT fluctuations. In Experiment 1, conflict adaptation was observed in an oddball condition in which interference emanates from a task-irrelevant and response-neutral low-frequency stimulus. This finding characterizes intermodal control adjustments to be based - at least partly - on increased sensory selectivity, which is able to improve performance in any kind of interference condition which shares the same or overlapping attentional requirements. In order to further specify this attentional mechanism, Experiment 2 defined analogous conflict adaptation effects in non-interference unimodal trials in which just one of the two stimulus modalities was presented. Conflict adaptation effects in unimodal trials exclusively occurred for unimodal task-switch trials but not for otherwise equivalent task repetition trials, which suggests that the observed conflict-triggered control adjustments mainly consist of increased distractor inhibition (i.e., down-regulation of task-irrelevant information), while attributing a negligible role to target amplification (i.e., enhancement of task-relevant information) in this setup. This behavioral study yields a promising operational basis for subsequent neuroimaging investigations to define brain activations and connectivities which underlie the adaptive control of attentional selection.