Sequential dependencies and children’s stimulus alternation

Stimulus and response alternation in young children.

“…On the other hand, Glanzer's deduction that subjects should alternate stimuli if the positions of the stimulus objects were changed from trial to trial was supported, and Harris' finding that children alternate stimuli was replicated. The failure to find a significant effect of stimulus duration replicated similar failures in two-choice situations in which stimulus alternation and response alternation were completely confounded (Croll, 1966;Rabinowitz, 1969). The children's comments as well as the experimenter's observation revealed a possible cause of the unexpected finding that the subjects alternated the low-meaningful stimuli (blocks) more than the high-meaningful stimuli (cars).…”

“…The response was usually a button press which resulted in the activation of a stimulus light. In these studies, both stimulus duration and stimulus discriminability have generally failed to affect stimulus alternation, contrary to Glanzer's predictions (e.g., Croll, 1966;Rabinowitz, 1969). Furthermore, it is reasonable to conclude from Rabinowitz' results that children alternate responses, not stimuli, since there was no significant difference in alternation between groups that could activate one stimulus (only response alternation possible) and groups that could activate two stimuli (both stimulus alternation and response alternation possible).…”

“…Two individual difference factors, age and sex, were also of interest in Experiment II. Using preschool children as subjects, Croll (1966) found a large decrement in stimulus alternation (stimulus alternation and response alternation completely confounded) across trial blocks, while Rabinowitz (1969) did not obtain this effect with third graders. There were also differences in the sequential dependencies exhibited by the subjects in the two studies.…”

“…Although the two factors described thus far are not related to Glanzer's theory, a third factor, stimulus discriminability, which plays a prominent role in the theory was also investigated. The failure of increasing stimulus discriminability to correlate with increasing stimulus alternation in prior studies (e.g., Iwahara, 1959;Rabinowitz, 1969) might have resulted from the complete confounding of stimulus alternation and response alternation. If response-alternation tendencies could appear in place of stimulusalternation tendencies as the stimuli became less discriminable, then significant effects would not be expected.…”

“…The independent assessment of stimulus alternation and response alternation in twochoice situations could provide the key to an apparent inconsistency. For example, Rabinowitz (1969) might not have obtained differences in alternation between groups that could activate one stimulus (only response alternation possible) and groups that could activate two stimuli (both response alternation and stimulus alternation possible) for two reasons. The subjects' stimulus-alternation tendencies might dominate their response-alternation tendencies; that is, if stimulus alternation was possible, then response alternation would not occur.…”