Movement of visual attention

One of widespread metaphors for visual attention is that it acts as if shining a spotlight on the visual field. This spotlight metaphor indicates that attention selects a place at which to enhance the efficiency of information processing and this is supported by a number of experiments. The spotlight metaphor, furthermore, suggests that the attentional beam can move smoothly as would a spotlight. Contrary to spatial selection, this part of the metaphor is controversial. Although there are several reports in the literature that suggest the smooth motion of visual attention, several researchers have pointed out serious methodological problems of these reports. The results of these reports may be explained with shifts of attention that discretely jumps. Since saccadic eye movements (jumpy eye movements to shift the line of sight) are thought to follow the attentional spotlight, attention may be a mechanism to shift discretely. On the other hand, attention may shift smoothly when observers are tracking smoothly moving objects. Previous reports measured the effect of reaction time speeding by pre-cues, which is assumed to attract attention at a location. Shifting attention to the pre-cued location may not elicit smooth shifts in attention. In this report, we introduce a paradigm to measure the location of attention while tracking a moving object to examine whether attention moves smoothly in such cases, and show evidence that support the smooth motion of attention.