What is the main factor in Sequential Theory that affects an animal's memory during extinction?

In Sequential Theory, the primary factor affecting an animal's memory during extinction is the association with the nonreward experience. This theory posits that when an animal learns to associate a particular stimulus or action with a reward, the subsequent absence of that reward leads to a change in the behavior and memory of the animal.

During the extinction phase, the animal's previous experience of receiving rewards becomes contrasted with the new experience of not receiving any rewards despite the previously learned behavior. This lack of reward reinforces the association with nonreward experiences and may facilitate the extinction process, as the animal begins to modify its behavior based on the new information that no longer supports the previous rewarded association.

The other factors, while they might have some influence, do not play as significant a role in this specific context. For instance, the presence of reward (the first option) would typically prevent extinction from occurring rather than affect memory during extinction. The frequency of responses and the physical environment can influence learning and recall but are secondary to the critical association made between the learned behavior and the absence of reward in this theoretical framework.