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 operatio ns. In contrast, simple and choice saccadic latencies (SL - time elapsing f rom stimulus onset to saccade initiation) are quite similar, suggesting tha t such responses may be more automated. In the present investigation, SL an d saccadic reaction times (SR - time elapsing from stimulus onset to saccad e 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 lo cal elements as indicators of required saccade direction. In addition, meas ures 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 o r global response times. Both global precedence and consistency effects wer e observed. Robust sequence learning was observed under the local condition , but only in the choice condition were all subjects able to recall the seq uence correctly. These results are discussed in terms of proposed models of visual perception and saccade generation based on parallel processing.