THE EFFECTS OF THE AMOUNT AND VARIABILITY OF PRACTICE ON THE LEARNINGOF A MULTI-SEGMENTED MOTOR TASK

Since the Shea, J.B. and Morgan (1979) study, investigators have repea tedly shown that the learning of a set of movement patterns (as evalua ted in a retention test) is enhanced when acquisition occurred under a random rather than a blocked schedule of practice. Supposedly, this i s the case because a random schedule of practice necessitates more ela borate cognitive activities than a blocked schedule before each acquis ition trial can be initiated. Our main objective was to determine whet her the advantage for learning found for random practice increases as a function of the number of acquisition trials. During acquisition, th e results indicated a general tendency for smaller movement reproducti on errors under a blocked rather than a random schedule of practice. H owever, this effect disappeared with larger amount of acquisition tria ls. In retention, larger errors were observed when acquisition occurre d under a blocked rather than a random schedule of practice. Finally, the disadvantage for learning observed for the blocked schedule of pra ctice disappeared under a block-repeated condition in which each movem ent pattern was first practiced under a blocked schedule which was the n repeated a second time. The results are discussed in terms of the so -called contextual interference effect and indicates some of its limit ations.