The effects of target distinctiveness, target placeholders, and target spatial separation on the relation between exogenous attention and temporal resolution were examined in a visual temporal order judgement (TOJ) task. When identical targets were presented at different locations within a cued or uncued placeholder, attention degraded temporal resolution (Experiment 1), but when distinct targets were presented at different locations that cueing effect disappeared (Experiment 2), and when the target placeholders were not used, attention enhanced temporal resolution for distinct targets presented at different locations (Experiment 3). Attention also degraded temporal resolution when distinct targets were presented at the same location (Experiment 4). The latter two results were then replicated in a task in which distinct targets appeared randomly at the same or different locations (Experiment 5). Clearly, the nature of the relation between exogenous attention and temporal resolution is not a straightforwar...

Object-based perception mediates the effect of exogenous attention on temporal resolution

Attentional blink (AB) speaks to a phenomenon that, when reporting two targets in a rapid serial visual presentation, the second target (T2) is often missed if it followed the first target (T1) within an interval of less than 500 ms. An interesting exception is the preserved performance of T2 at Lag 1 position (Lag-1 sparing), or even in an extended period, which recently has been termed temporal integration. Both T1 and T2 can be successfully reported but with a loss of their temporal order. The integration has been attributed to the temporal distance between the two targets. However, previous studies on temporal perception have revealed that similarity between two stimuli modulated their temporal order judgment, suggesting that temporal integration is affected by stimulus characteristics. In the present study, we investigated whether stimulus characteristics modulated temporal integration in the AB. We manipulated the categorical similarity between T1 and T2 targets and found that the order reversals were significantly higher in the same-category condition than that in the different-category condition. Our results thus provided clear evidence for the contribution of categorical similarity to the temporal integration in the AB.

Categorical similarity modulates temporal integration in the attentional blink

Transient attention impairs observers’temporal resolution in a cued location. This detrimental effect of attention was ascribed to inhibitory connections from parvocellular to magnocellular neurons (1). Alternatively, the difficulty might arise because attention facilitates the temporal summation of two successive stimuli. The current study examined this hypothesis by manipulating the luminance polarity of the stimuli against a background. Attention should not modulate temporal summation of two anti-polar stimuli because these are processed in separate channels. Indeed, observers judged the temporal order of two successive stimuli better in the cued location than in the uncued location when the stimuli were opposite in polarity, but temporal resolution was worse in the cued location when the stimuli had the same polarity. Thus, attentional effects on temporal resolution may be attributed to temporal summation rather than parvocellular inhibition of magnocellular activity.

Keetaek Kham

Papers

Spatial Attention Can Enhance or Impair Visual Temporal Resolution