Effects of Three Levels of Interpolated Activity on the Acquisition of a Simple Motor Skill

96 male students performed for 20 min. on a pursuit rotor with either the preferred hand ( P) or non-preferred ( Np) hand. Practice was either Massed ( M), Spaced ( Sp) or Switched ( Sw) which required S to switch hands during alternate 30-sec. practice periods. The results show an over-all difference between hands ( P > Np) and among practice conditions ( Sp > Sw > M) but the observed intermediate position of Sw was uninterpretable since either dissipation of inhibition or transfer of training could have produced this effect.