Patterning,partial reinforcement,and N-length effects at spaced trials as a function of reinstatement of retrieval cues

Four experiments are reported which demonstrate the importance of the reinstatement of retrieval cues in partial-reinforcement experiments using spaced trials. Reinstatement occurs when the goalbox and startbox are of the same brightness (gray). Nonreinstatement occurs when the goalbox and startbox are of different brightnesses (black-and-white striped vs gray). Under reinstatement conditions, both a partial-reinforcement effect (PRE) and N-length effects were observed whether small reward or large reward was used. Under nonreinstatement conditions, a PRE was observed when large reward was used but not when small reward was used; N-length effects were not observed either with large or small reward. Finally, using a 24-hr intertrial interval, single alternation patterning was found only with a group receiving large reward, a long nonreward confinement duration, and reinstatement. These results are not consistent with the notion that massed and spaced trials are governed by separate mechanisms, and support an explanation of both massed and spaced trials based on E. J. Capaldi's sequential theory.