Spaced practice as a test of Snoddy's two processes in mental growth.

Abstract

The learning task consisted of the visual-manual coordination of the Koerth pursuit rotor. 2 groups of 25 subjects (university students) scored alike on initial trials under comparable conditions. In order to test a theorem based on Snoddy''s characterizations of primary and secondary growth, one group practiced with decreasing intervals betwen 1-min. practice trials, the other with increasing intervals. Both groups practiced the same no. of trials, covering the same total period of 43 mins. Contrary to the theorem based on Snoddy, massing of trials was found to be more disadvantageous late than early in practice. An alternative analysis was suggested by Snoddy''s analysis into primary and secondary growth.