Saccadic latency during perceptual processing and sequence learning.

The difference between simple and choice manual reaction time (RT) has been taken to be a measure of the time necessary for various cognitive operations. In contrast, simple and choice saccadic latencies (SL - time elapsing from stimulus onset to saccade initiation) are quite similar, suggesting that such responses may be more automated. In the present investigation, SL and saccadic reaction times (SR - time elapsing from stimulus onset to saccade completion) were measured for targets appearing in the same and different locations, and to different ends of compound stimuli (big arrows) composed of small elements (little arrows) using either the global figure or the local elements as indicators of required saccade direction. In addition, measures of sequence learning were obtained behaviorally over iterative trials (decreases in response time) and with post-test interrogation. The results indicated that local response times were significantly slower than choice or global response times. Both global precedence and consistency effects were observed. Robust sequence learning was observed under the local condition, but only in the choice condition were all subjects able to recall the sequence correctly. These results are discussed in terms of proposed models of visual perception and saccade generation based on parallel processing.