Massed practice improves learning of serial motor skills

Memory encompasses the ability to encode, store, and consolidate information. Temporal spacing between events can influence information processing in working memory and impact memory consolidation. The effects of inter-trial spacing on working memory can be investigated by manipulating practice distribution. However, the effects of the spacing of practice on serial motor skill learning remain unknown. This study manipulated two different inter-trial intervals during the learning of a serial motor skill. We recruited 30 children, mean age of 9.4 ± 0.8 years, with no prior experience in the task of sequentially pressing four keys on a computer numeric keypad. Participants were randomly assigned into either a massed practice condition with a 2-s inter-trial interval or a distributed practice condition with a 30-s inter-trial interval. After 24 hr, testing phase was conducted in both massed and distributed conditions. We found that a short inter-trial interval promoted better memory consolidation and learning in both retention conditions, with massed practice demonstrating greater consistency than distributed practice in the distributed retention test. These findings suggest that shorter inter-trial intervals enhance memory consolidation and improve serial motor skill learning. We propose a different theoretical framework based on decay theory to explain the role of practice distribution in memory consolidation and learning.