At any moment in time, streams of information reach the brain through the different senses. Given this wealth of noisy information, it is essential that we select information of relevance - a function fulfilled by attention - and infer its causal structure to eventually take advantage of redundancies across the senses. Yet, the role of selective attention during causal inference in cross-modal perception is unknown. We tested experimentally whether the distribution of attention across vision and touch enhances cross-modal spatial integration (visual-tactile ventriloquism effect, Expt. 1) and recalibration (visual-tactile ventriloquism aftereffect, Expt. 2) compared to modality-specific attention, and then used causal-inference modeling to isolate the mechanisms behind the attentional modulation. In both experiments, we found stronger effects of vision on touch under distributed than under modality-specific attention. Model comparison confirmed that participants used Bayes-optimal causal inference to localize visual and tactile stimuli presented as part of a visual-tactile stimulus pair, whereas simultaneously collected unity judgments - indicating whether the visual-tactile pair was perceived as spatially-aligned - relied on a sub-optimal heuristic. The best-fitting model revealed that attention modulated sensory and cognitive components of causal inference. First, distributed attention led to an increase of sensory noise compared to selective attention toward one modality. Second, attending to both modalities strengthened the stimulus-independent expectation that the two signals belong together, the prior probability of a common source for vision and touch. Yet, only the increase in the expectation of vision and touch sharing a common source was able to explain the observed enhancement of visual-tactile integration and recalibration effects with distributed attention. In contrast, the change in sensory noise explained only a fraction of the observed enhancements, as its consequences vary with the overall level of noise and stimulus congruency. Increased sensory noise leads to enhanced integration effects for visual-tactile pairs with a large spatial discrepancy, but reduced integration effects for stimuli with a small or no cross-modal discrepancy. In sum, our study indicates a weak a priori association between visual and tactile spatial signals that can be strengthened by distributing attention across both modalities.

中文翻译：

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模态特定的注意力通过减少对视觉和触觉共同来源的先前期望来减弱视觉触觉整合和重新校准效果。

在任何时候，信息流都会通过不同的感官到达大脑。鉴于大量嘈杂的信息，我们必须选择相关信息（一种由注意力实现的功能）并推断其因果结构以最终利用感官上的冗余。然而，选择性注意在跨模态感知中的因果推断过程中的作用尚不清楚。我们通过实验测试了注意力在视觉和触觉上的分布是否增强了跨模式空间整合（视觉-触觉腹语效应，实验 1）和重新校准（视觉-触觉腹语后效，实验 2）与模式特定的注意力相比，以及然后使用因果推理模型来隔离注意力调制背后的机制。在这两个实验中，我们发现在分布式注意力下视觉对触觉的影响比在特定模式注意下更强。模型比较证实，参与者使用贝叶斯最优因果推理来定位作为视觉-触觉刺激对的一部分呈现的视觉和触觉刺激，同时收集统一判断——表明视觉-触觉对是否被认为是空间对齐的——依赖于次优启发式。最佳拟合模型显示，注意力调节了因果推理的感官和认知成分。首先，与对一种模态的选择性注意相比，分布式注意导致感觉噪音的增加。其次，关注这两种模式增强了两种信号属于一起的独立于刺激的期望，视觉和触觉共同来源的先验概率。然而，只有对视觉和触觉共享一个共同来源的期望的增加才能解释观察到的视觉触觉整合和分布式注意力重新校准效果的增强。相比之下，感官噪声的变化仅解释了观察到的增强的一小部分，因为其后果随噪声和刺激一致性的整体水平而变化。增加的感觉噪声会导致具有较大空间差异的视觉-触觉对的整合效应增强，但会降低具有较小或没有跨模态差异的刺激的整合效应。总之，我们的研究表明视觉和触觉空间信号之间的先验关联很弱，可以通过在两种方式上分配注意力来加强这种关联。只有对视觉和触觉共享一个共同来源的期望的增加能够解释观察到的视觉触觉整合和分布式注意力重新校准效果的增强。相比之下，感官噪声的变化仅解释了观察到的增强的一小部分，因为其后果随噪声和刺激一致性的整体水平而变化。增加的感觉噪声会导致具有较大空间差异的视觉-触觉对的整合效应增强，但会降低具有较小或没有跨模态差异的刺激的整合效应。总之，我们的研究表明视觉和触觉空间信号之间的先验关联很弱，可以通过在两种方式上分配注意力来加强这种关联。只有对视觉和触觉共享一个共同来源的期望的增加能够解释观察到的视觉触觉整合和分布式注意力重新校准效果的增强。相比之下，感官噪声的变化仅解释了观察到的增强的一小部分，因为其后果随噪声和刺激一致性的整体水平而变化。增加的感觉噪声会导致具有较大空间差异的视觉-触觉对的整合效应增强，但会降低具有较小或没有跨模态差异的刺激的整合效应。总之，我们的研究表明视觉和触觉空间信号之间的先验关联很弱，可以通过在两种方式上分配注意力来加强这种关联。