PURPOSE: The spotlight of attention is full of discrete moments and operates periodically. Recently, several psychophysics studies investigate behavioral oscillation in visual attention, but they found different periodicities. Task difficulty might be one of important factors which caused disagreement in attentional periodic patterns. In the present study, behavioral oscillations in visual attention during difficult and easy tasks were examined.
METHODS: A modified high temporal resolution cue-target paradigm, the cue-target SOA varied from 0.1 s to 1.08 s in steps of 20 ms, was used. In difficult condition, target was detected successfully at 65%. While, 75% in easy condition.
RESULTS: We found a theta rhythm in difficulty version, consistent with previous studies. While, in the easy version, attention oscillation increased to a higher frequency. Additionally, task difficulty negatively related to power for all bands.
CONCLUSIONS: Our findings suggest that when task was easy, attention spotlight switched faster. If task was difficult, it switched much slower to get more information. A flexible mechanism for attention spotlight and this could be modulated by task demand.