Attention Increases the Temporal Precision of Conscious Perception: Verifying the Neural-ST2 Model

What role does attention play in ensuring the temporal precision of visual perception? Behavioural studies have investigated feature selection and binding in time using fleeting sequences of stimuli in the Rapid Serial Visual Presentation (RSVP) paradigm, and found that temporal accuracy is reduced when attentional control is diminished. To reduce the efficacy of attentional deployment, these studies have employed the Attentional Blink (AB) phenomenon. In this article, we use electroencephalography (EEG) to directly investigate the temporal dynamics of conscious perception. Specifically, employing a combination of experimental analysis and neural network modelling, we test the hypothesis that the availability of attention reduces temporal jitter in the latency between a target's visual onset and its consolidation into working memory. We perform time-frequency analysis on data from an AB study to compare the EEG trials underlying the P3 ERPs (Event-related Potential) evoked by targets seen outside vs. inside the AB time window. We find visual differences in phase-sorted ERPimages and statistical differences in the variance of the P3 phase distributions. These results argue for increased variation in the latency of conscious perception during the AB. This experimental analysis is complemented by a theoretical exploration of temporal attention and target processing. Using activation traces from the Neural-ST2 model, we generate virtual ERPs and virtual ERPimages. These are compared to their human counterparts to propose an explanation of how target consolidation in the context of the AB influences the temporal variability of selective attention. The AB provides us with a suitable phenomenon with which to investigate the interplay between attention and perception. The combination of experimental and theoretical elucidation in this article contributes to converging evidence for the notion that the AB reflects a reduction in the temporal acuity of selective attention and the timeliness of perception.Author Summary: Our visual system keeps pace with a rapidly changing stream of information as we view the natural world. To do so, it uses a strongly regulated system of attentional filters to constrain which visual stimuli are permitted to be fully processed to the level of conscious awareness. This article explores what happens when these filters are opened and closed in response to important visual stimuli. To understand these dynamics, our neural network model provides simulations of the role played by attention. These simulations can be tested by recording neural data in the form of ‘brain waves’ (EEG) and comparing the resultant signals to the output of the model. The data discussed here confirm a prediction of the model, which suggests that after the attentional filter has opened to allow one visual stimulus in, there is increased temporal variability or ‘jitter’ in the subsequent opening of the filter within an interval of about one-half of a second. These results have implications for the way our brains process multiple important stimuli perceived in rapid succession, such as the sequence of events that might occur at a critical moment in an airline cockpit or during an automobile accident.