THE CONTEXTUAL INTERFERENCE EFFECT IN PARAMETER MODIFICATIONS OF THE SAME GENERALIZED MOTOR PROGRAM

This study extended previous work (Sekiya, Magill, Sidaway, & Anderson , 1994) by examining whether the contextual interference (CI) effect c ould be found when task variations were controlled by the same general ized motor program (GMP) but differentiated on the basis of overall fo rce parameter modifications. A subsidiary aim of this study was to det ermine how the amount of practice influenced the CI effect. During 2 a cquisition sessions and 2 retention sessions, participants (N=24) perf ormed 3 task variations in either a blocked (low CI) or serial (high C I) condition. The task variations shared the same relative force struc tures but differed in the amount of overall force that had to be produ ced. Analysis of a general error measure revealed a strong CI effect, indicating that overall force parameter modifications of the same GMP created the CI effect. Analyses of various dependent measures, which d issociated GMP from parameter components with regard to force characte ristics, revealed that parameter learning but not GMP learning, was en hanced by high CI practice. No CI effect occurred in any aspect of tim ing characteristics. The amount of practice used in the present study did not influence the efficacy of the CI effect.