Testing the validity of a non-associative theory of Pavlovian learning, Rate Estimation Theory (RET)
Abstract: The current dissertation tested the validity of a non-associative account of Pavlovian conditioning. Pavlovian conditioning involves the presentation of an arbitrary stimulus (the CS) followed by a stimulus that elicits an innate response (the US), such as food. After at least one presentation of the CS-US pairing, responding begins to develop to the presentation of the CS alone (the CR). Associative theories claim that the CR develops as a result of the association between the CS and the US strengthening. An alternative, non-associative account of Pavlovian conditioning, Rate Estimation Theory (RET), has been proposed. In this theory, the CR develops when the ratio of the rate of US occurrences during the CS presentation (T) exceeds the rate of US occurrences when the subject is in the experimental environment (I) and the CS is absent vi by a specific amount, or a large I/T ratio. The present dissertation tested the validity of RET. In Experiments 1 and 2, RET’s claim that the order of occurrence of the context exposure and the CS presentation do not affect the CR was tested. The results of these tests indicated that, contrary to RET, the order of presentation of these components of the conditioning trial did affect the CR. In Experiment 3, it was tested whether an alternative type of CR, goal tracking, was elicited in a similar pattern as the CR described by RET. RET only allows for one type of CR, sign tracking. The results indicated that the pattern of goal tracking was not the same as the pattern of sign tracking. Experiments 4, 5, and 6 tested the effect of the CS type on the development of the CR. Contrary to RET’s prediction that the CS type has no effect on the CR, CSs of higher visual salience elicited more approach responding to the CS than did less visually salient CSs. Contrary to RET’s claim that the I/T ratio is the sole determiner of the CR, the results of the present experiments indicated that the order of presentation of the I and the T, and the type of CS used affect the CR.