Visual processing involves spatial and temporal components, yet the investigation of visual processing has primarily focused on the spatial domain. The goal of this research is to contribute to our understanding of the temporal domain by studying its possible relationship to spatial attention. We have previously shown that spatial attention can sharpen spatial resolution (e.g., Yeshurun & Carrasco, 1998). Here we investigated whether this attentional mechanism can also affect temporal processes. Specifically, we explored the effects of spatial attention on: a) temporal resolution -the ability to resolve rapid intensity changes over time; b) estimation of temporal length -the ability to correctly estimate the length of a stimulus duration; and c) temporal integration -the ability to integrate information through time. In all three, classic paradigms for studying these temporal processes- such as measurements of two flash fusion threshold or visible persistence- were combined with the classic paradigm to manipulate transient spatial attention: A peripheral cue indicated the location of the target prior to its appearance, allowing observers to direct their attention in advance to the target location. The central questions raised were whether spatial attention can alter temporal processing as it alters spatial processing, and whether its effects on temporal processes depend on its effects on spatial processes. Results indicate that attending the target location lowered observers' temporal resolution, lengthened their estimation of stimulus duration and prolonged the time period over which information was integrated. An attentional mechanism that can account for both the attentional effects on spatial resolution as well as its effects on temporal processes will be suggested, and the relationships between these findings and other recent studies of attentional effects on temporal processes (e.g., visual masking, visible persistence) will be discussed.
ASJC Scopus subject areas
- Sensory Systems