Abstract
Visual motion captures attention, but little is known about the automaticity of these effects and the time required for the integration of motion signals to capture attention. Here, we tested if deviant frequencies as one form of motion automatically capture attention and whether integration across time results in a longer period of effective cueing by flicker than by single-transient cues. Observers searched for a vertical target among tilted distractors. Prior to the target display, a cue array of sinusoidally modulating annuli, each surrounding one location of the subsequent target (-plus-distractors) display was presented for variable durations. Annuli either flickered all at 1 Hz (no-singleton cue), or a single annulus flickered at a unique frequency of 5 Hz, 10 Hz, or 15 Hz. The location of this singleton-flicker cue was uncorrelated with target location. Thus, we could measure benefits (target at cued location) and costs (target ≠ cued location) for cues of different frequencies and durations. The results showed that deviant flicker frequencies capture attention, as we observed benefits and costs, falsifying that nonspatial filtering accounted for the cueing effect. In line with automatic capture, cueing was effective in a singleton (Experiment 1) and a non-singleton search task (Experiment 2), and is thus not due to top-down singleton search. Moreover, results held in analyses ruled out trial-by-trial ‘swapping’ of flicker frequencies at target and distractor locations. Results also revealed significant capture for cues with frequency separations from non-singleton flicker as low as 4 Hz at short cue durations (180 ms) and increasing cueing effects with higher cue frequencies and longer durations. This indicates a significantly longer period of automatic capture by sinusoidal flicker (up to 360 ms) than the typical inhibition of return observed ~250 ms after the onset of uninformative static or single-transient cues.