The role of conflict processing in multisensory perception: behavioural and electroencephalography evidence

Perceptual oddities: assessing the relationship between film editing and prediction processes

During film viewing, humans parse sequences of individual shots into larger narrative structures, often weaving transitions at edit points into an apparently seamless and continuous flow. Editing helps filmmakers manipulate visual transitions to induce feelings of fluency/disfluency, tension/relief, curiosity, expectation and several emotional responses. We propose that the perceptual dynamics induced by film editing can be captured by a predictive processing (PP) framework. We hypothesise that visual discontinuities at edit points produce discrepancies between anticipated and actual sensory input, leading to prediction error. Further, we propose that the magnitude of prediction error depends on the predictability of each shot within the narrative flow, and lay out an account based on conflict monitoring. We test this hypothesis in two empirical studies measuring electroencephalography (EEG) during passive viewing of film excerpts, as well as behavioural responses during an active edit detection task. We report the neural and behavioural modulations at editing boundaries across three levels of narrative depth, showing greater modulations for edits spanning less predictable, deeper narrative transitions. Overall, our contribution lays the groundwork for understanding film editing from a PP perspective. This article is part of the theme issue 'Art, aesthetics and predictive processing: theoretical and empirical perspectivess'.

How the brain controls decision making in a multisensory world

Sensory systems evolved to provide the organism with information about the environment to guide adaptive behaviour. Neuroscientists and psychologists have traditionally considered each sense independently, a legacy of Aristotle and a natural consequence of their distinct physical and anatomical bases. However, from the point of view of the organism, perception and sensorimotor behaviour are fundamentally multi-modal; after all, each modality provides complementary information about the same world. Classic studies revealed much about where and how sensory signals are combined to improve performance, but these tended to treat multisensory integration as a static, passive, bottom-up process. It has become increasingly clear how this approach falls short, ignoring the interplay between perception and action, the temporal dynamics of the decision process and the many ways by which the brain can exert top-down control of integration. The goal of this issue is to highlight recent advances on these higher order aspects of multisensory processing, which together constitute a mainstay of our understanding of complex, natural behaviour and its neural basis. This article is part of the theme issue 'Decision and control processes in multisensory perception'.

The role of conflict processing in multisensory perception: behavioural and electroencephalography evidence

To form coherent multisensory perceptual representations, the brain must solve a causal inference problem: to decide if two sensory cues originated from the same event and should be combined, or if they came from different events and should be processed independently. According to current models of multisensory integration, during this process, the integrated (common cause) and segregated (different causes) internal perceptual models are entertained. In the present study, we propose that the causal inference process involves competition between these alternative perceptual models that engages the brain mechanisms of conflict processing. To test this hypothesis, we conducted two experiments, measuring reaction times (RTs) and electroencephalography, using an audiovisual ventriloquist illusion paradigm with varying degrees of intersensory disparities. Consistent with our hypotheses, incongruent trials led to slower RTs and higher fronto-medial theta power, both indicative of conflict. We also predicted that intermediate disparities would yield slower RTs and higher theta power when compared to congruent stimuli and to large disparities, owing to the steeper competition between causal models. Although this prediction was only validated in the RT study, both experiments displayed the anticipated trend. In conclusion, our findings suggest a potential involvement of the conflict mechanisms in multisensory integration of spatial information. This article is part of the theme issue 'Decision and control processes in multisensory perception'.