Temporal and spatial characteristics of attention to facilitate manual andeye-movement responses

Previous investigation found that the speed of saccadic eye movements is en hanced when a temporal interval (gap) is introduced between the disappearan ce of a foveal fixation mark and the appearance of a peripheral target (the gap paradigm). Attention was shown to he involved in the gap paradigm. Her e, we investigated relevant temporal and spatial characteristics of attenti on, manipulating central fixation marks and peripheral targets. Results fro m three experiments indicate that (i) the speed of manual and eye-movement detection is accelerated when a fixation mark changes abruptly (in less tha n 100 ms) before its termination in the gap paradigm; (ii) the speed is fur ther accelerated when a peripheral target location is pre-cued; (iii) suffi cient time for fixation (1000 ms) is necessary for the facilitation. These results suggest that fast and transient attention at the fixation spot faci litates attentional disengagement process that urges a spatial-orienting me chanism. Sustained attention is required in the engagement process during t he fixation.