UVM Theses and Dissertations
Format:
Print
Author:
Woods, Amanda M.
Dept./Program:
Psychology
Year:
2010
Degree:
PhD
Abstract:
Seven experiments compared the effects of immediate and delayed extinction on the durability of extinction learning in rats. Experiments 1-4 involved the conditioned emotional response (CER) method, and Experiments 5-7 involved the food-cup entry appetitive conditioning method. In all experiments, conditioning and extinction involved single sessions, and retention testing occurred either 24 or 48 hr after extinction. In both the fear and appetitive methods, immediate extinction (which began 10 min after conditioning) caused a faster loss of conditioned responding than delayed extinction (which began 24 hr after conditioning).
However, immediate extinction resulted in stronger spontaneous recovery during the retention test (Experiments 1 and 5), suggesting that it is less durable than delayed extinction. There was also significant renewal when the physical context was changed after immediate extinction. The pattern of results was the same when additional extinction trials were given (Experiment 2) and when the time between conditioning and testing was controlled (Experiments 3 and 6). Experiments 4 and 7 revealed that the poor durability of immediate extinction is not due to due to either a mismatch in the "context" provided by the presence or absence of a recent conditioning experience (Bouton, 1993) or a high level of fear during extinction (Maren & Chang, 2006).
Overall, the results suggest that, in these two widely-used conditioning preparations, immediate extinction does not erase or depotentiate original learning . (Myers, Ressler, & Davis, 2006), but instead creates a less permanent reduction in conditioned responding. Several theoretical accounts ofthe results are considered. At present the most comprehensive explanation ofthe data is provided by a contextual model that extends the ideas of Bouton (1993) and states that recovery is more likely after immediate than delayed extinction because of a greater degree of change in the temporal context as time passes after immediate extinction.
However, immediate extinction resulted in stronger spontaneous recovery during the retention test (Experiments 1 and 5), suggesting that it is less durable than delayed extinction. There was also significant renewal when the physical context was changed after immediate extinction. The pattern of results was the same when additional extinction trials were given (Experiment 2) and when the time between conditioning and testing was controlled (Experiments 3 and 6). Experiments 4 and 7 revealed that the poor durability of immediate extinction is not due to due to either a mismatch in the "context" provided by the presence or absence of a recent conditioning experience (Bouton, 1993) or a high level of fear during extinction (Maren & Chang, 2006).
Overall, the results suggest that, in these two widely-used conditioning preparations, immediate extinction does not erase or depotentiate original learning . (Myers, Ressler, & Davis, 2006), but instead creates a less permanent reduction in conditioned responding. Several theoretical accounts ofthe results are considered. At present the most comprehensive explanation ofthe data is provided by a contextual model that extends the ideas of Bouton (1993) and states that recovery is more likely after immediate than delayed extinction because of a greater degree of change in the temporal context as time passes after immediate extinction.