A noted on the relationship between task requirements and the contextual interference effect

Typically, tasks used in past contextual interference experiments had movement, spatial pattern, or timing requirements. The possibility exists that the blocked/random manipulation of only one of these task characteristics contributes to the contextual interference effect. The purpose of the experiment reported here was to test the impact of separate movement and timing tasks on the superior learning of random trained groups. The task for all subjects in the movement condition was to release a start button and knock over a wooden barrier. There were three movement goals to be learned. Half of the subjects in this condition practiced the three movements in a blocked schedule and half practiced them in a random schedule. The subjects in the no-movement condition estimated the same three times by holding down the start button for the appropriate duration. Similarly, these subjects were divided into random and blocked practice groups. All subjects then performed a retention test. Results showed that for the movement condition, the blocked group performed with less error than the random group during acquisition. In retention, however, the random group performed with less error than the blocked group. conversely, for the no-movement condition, there were no differences between the two practice schedule groups during acquisition or during retention for any of the dependent measures. These results indicated that experimental tasks must have some type of movement requirement in order to facilitate learning through the use of random practice schedules.