Differential Eyelid Conditioning as a Function of CS-UCS Interval and Distance Separating the CSS

Human Ss were given differential eyelid conditioning at CS-UCS intervals of 400, 600, and 800 msec. to visual CSs separated by 1.25 and 2.50 in. The CS outlines were not visible to S during the intertrial interval as they customarily are in spatial discrimination tasks. CS+ response levels increased with interval throughout the range employed with CS− levels increasing only through 600 msec. No differentiation was observed at 400 and 600 msec. intervals at either level of separation. These results indicate that CS-UCS interval functions in differential conditioning cannot be generally defined and must be related to the conditions employed in a given experiment.