Probability-driven and stimulus-driven orienting of attention to time and sensory modality

Abstract

The timing and the sensory modality of behaviorally relevant events often vary predictably, so that it is beneficial to adapt the sensory system to their statistical regularities. Indeed, statistical information about target timing and/or sensory modality modulates behavioral responses-called expectation effects. Responses are also facilitated by short-term repetitions of target timing and/or sensory modality-called priming effects. We examined how the expectation and priming effects on target timing (short vs. long cue-to-target interval) and target modality (auditory vs. visual) interacted. Temporal expectation was manipulated across blocks, while modality expectation was manipulated across participants. Responses were faster when targets were presented at the expected timing and/or in the expected modality in an additive manner, suggesting that temporal and modality expectation operate relatively independently. Similarly, responses were faster when the timing and/or modality of targets was repeated across trials in an additive manner, suggesting that temporal and modality priming operate relatively independently. Importantly, the interactions between expectation and priming were domain specific. In the temporal domain, temporal-expectation effects were observed only when temporal-priming effects were absent. In the modality domain, modality-priming effects predominated for auditory targets whereas modality-expectation effects predominated for visual targets. Thus, the interactions between probability-driven expectation and stimulus-driven priming processes appear to be controlled separately for the mechanisms that direct attention to specific temporal intervals and for the mechanisms that direct attention to specific sensory modalities. These results may suggest that the sensory system concurrently optimizes attentional priorities within temporal and sensory-modality domains.

Keywords: Attention: Selective; Temporal processing.

Figure 1.

Experimental design and sequences of trial events. To manipulate modality expectation, half of the participants were assigned to the auditory-expected group who frequently (80%) received auditory targets (left column) and infrequently (20%) received visual targets (right column), while the remaining participants were assigned to the visual-expected group who frequently (80%) received visual targets and infrequently (20%) received auditory targets. To orthogonally manipulate temporal expectation, for each group, the cue-to-target intervals were frequently (80%) short and infrequently (20%) long in the short-expected block and frequently (80%) long and infrequently (20%) short in the long-expected block. Participants were instructed to indicate whether the target letter was “B” or “D” regardless of the modality of presentation, spoken (left column) or displayed (right column).

Figure 2.

The effects of temporal expectation and modality expectation on RT. The error bars represent ±1 standard error of the mean, adjusted for within-participants comparisons (Morey, 2008).

Figure 3.

The effects of temporal priming and modality priming on RT. The error bars represent ±1 standard error of the mean, adjusted for within-participants comparisons (Morey, 2008).

Figure 4.

The effects of temporal expectation and temporal priming on RT. The error bars represent ±1 standard error of the mean, adjusted for within-participant comparisons (Morey, 2008).

Figure 5.

The effects of modality expectation and modality priming on RT shown separately for the auditory-expected (left panel) and visual-expected (right panel) groups. The error bars represent ±1 standard error of the mean, adjusted for within-participants comparisons (Morey, 2008).

Figure 6.

A replotting of Figure 5 where the effects of modality expectation and modality priming on RT are shown separately for the auditory-target (left panel) and visual-target (right panel) trials (rather than for the auditory-expected and visual-expected groups). The error bars represent ±1 standard error of the mean, adjusted for within-participants comparisons (Morey, 2008). Note that because we separated the auditory-target and visual-target trials, modality expectation within each panel is a between-participant factor (shapes connected with dashed lines). Thus, the error bars are appropriate for assessing the effect of modality priming and its interaction (or lack thereof) with modality expectation, but are inappropriate for assessing the effect of modality. expectation.