1. the assumption that successful discrimination learning or problem solving results from a progressive, incremental, continuous process of trial and error. Responses that prove unproductive are extinguished, whereas every reinforced response results in an increase in associative strength, thus producing the gradual rise of the learning curve. Problem solving is conceived as a step-by-step learning process in which the correct response is discovered, practiced, and reinforced. Compare discontinuity hypothesis.

2. the contention that psychological processes of various kinds (e.g., learning, childhood development) take place either in small steps or continuously, rather than in jumps or discontinuously from one identifiable stage to another. Also called continuity theory.