Attention modulates incidental memory encoding of human movements

Incidental temporal binding in rats: A novel behavioral task

We designed a behavioral task called One-Trial Trace Escape Reaction (OTTER), in which rats incidentally associate two temporally discontinuous stimuli: a neutral acoustic cue (CS) with an aversive stimulus (US) which occurs two seconds later (CS-2s-US sequence). Rats are first habituated to two similar environmental contexts (A and B), each consisting of an interconnected dark and light chamber. Next, rats experience the CS-2s-US sequence in the dark chamber of one of the contexts (either A or B); the US is terminated immediately after a rat escapes into the light chamber. The CS-2s-US sequence is presented only once to ensure the incidental acquisition of the association. The recall is tested 24 h later when rats are presented with only the CS in the alternate context (B or A), and their behavioral response is observed. Our results show that 59% of the rats responded to the CS by escaping to the light chamber, although they experienced only one CS-2s-US pairing. The OTTER task offers a flexible high throughput tool to study memory acquired incidentally after a single experience. Incidental one-trial acquisition of association between temporally discontinuous events may be one of the essential components of episodic memory formation.

Integration or separation? Spatial and temporal representations of whole-body movements in visual working memory

Spatial and temporal information are two major feature dimensions of human movements. How these two types of information are represented in working memory-whether as integrated units or as individual features-influences how much information might be retained and how the retained information might be manipulated. In this study, we investigated how spatial (path/trajectory) and temporal (speed/rhythm) information of complex whole-body movements are represented in working memory under a more ecologically valid condition wherein the spatiotemporal continuity of movement sequences was considered. We found that the spatial and temporal information are not automatically integrated but share the storage capacity and compete for a common pool of cognitive resources. The finding rejects the strong form of object-based representation and supports the partial independence of spatial and temporal processing. Nevertheless, we also found that contextual factors, such as the way movements are organized and displayed, can further modulate the level of object-based representation and spatiotemporal integration.

Effects of spatiotemporal (dis)continuity on working memory for human movements

Human movements are dynamic and continuous in nature. However, how the spatiotemporal continuity influences working memory for movements is still unclear. Specifically, spatiotemporal continuity of movements may facilitate integrative processing ("integration") and enhance memory performance by optimizing the encoding process, but it may also diminish memory benefits from distinctive processing ("separation"). In this study, we manipulated the continuity state (continuous/discontinuous) (Experiment 1) and its predictability (Experiment 2) of whole-body movement sequences and tested participants' working memory for observed movements with a single-probe recognition task. We formulated potential influence from spatiotemporal (dis)continuity by two opposite forces - integration vs. separation, and demonstrated a conflict between these two processes across space and time. Moreover, we found that the seemingly stimulus-driven perceptual effects from spatiotemporal (dis)continuity might be supported by a prediction-based mechanism, which guided the selection of an optimal processing strategy. Overall, our finding illustrates an interweaving relationship between spatial and temporal processing during action observation and highlights the importance of considering the dynamic and continuous nature of human movements in visual perception and working memory research.