Development of a mechanism for detection of error and retention of a graded motor response

Several methods for developing an internal mechanism for error detection were compared to determine the extent to which a self-paced response could be acquired and retained without knowledge of results. During training, blindfolded subjects attempted to learn a positioning response under one of three conditions. One group was presented with the criterion end location by means of a stop and then required to recall the location with the stop removed. A second group moved the total distance of the track and then was instructed to replace the slide in a location representing a specific fraction of the total. A final group of subjects learned the criterion location by using post-response knowledge of results administered on each trial. Following acquisition subjects were give retention trials involving only repetition of the acquired response. The development of a strong mechanism for error detection was indicated only for those groups presented with the standard or with post-response knowledge of results. During retention trials (without knowledge of results), performance of the group required to learn the criterion by estimating a fraction of the total range was characterized by significanlty greater response biasing and less consistency than the other conditions. The findings were discussed in terms of several predictions from Adams' (1971) closed-loop theory of motor learning.