To test the discrimination hypothesis of the partial reinforcement effect in extinction, partial or continuous reinforcement trials were interpolated between the initial training trials of partial or continuous reinforcement and the extinction period. 112 children from Grades 2 and 3 participated in one of four conditions. Children receiving two consecutive blocks of partial reinforcement showed the greatest resistance to extinction, children receiving two consecutive blocks of continuous reinforcement showed the weakest resistance, and those receiving partial reinforcement followed by continuous reinforcement or vice versa showed intermediate levels of resistance. Discrimination between training and extinction does not seem to be the critical factor involved in the partial reinforcement effect. The results were discussed in terms of a stimulus analyzer or a sequential analysis model.