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Vivid episodic memories in humans have been described as the replay of the flow of past events in sequential order. Recently, Panoz-Brown et al. (2018) developed an olfactory memory task in which rats were presented with a list of trial-unique odors in an encoding context; next, in a distinctive memory assessment context, the rats were rewarded for choosing the second to last item from the list while avoiding other items from the list. In a different memory assessment context, the fourth to last item was rewarded. According to the episodic memory replay hypothesis, the rat remembers the list items and searches these items to find the item at the targeted locations in the list. However, events presented sequentially differ in memory trace strength, allowing a rat to use the relative familiarity of the memory traces, instead of episodic memory replay, to solve the task. Here, we directly manipulated memory trace strength by manipulating the odor intensity of target odors in both the list presentation and memory assessment. The rats relied on episodic memory replay to solve the memory assessment in conditions in which reliance on memory trace strength is ruled out. We conclude that rats are able to replay episodic memories. 

Goal reasoning agents can solve novel problems by detecting an anomaly between expectations and observations; generating explanations about plausible causes for the anomaly; and formulating goals to remove the cause. Yet not all anomalies represent problems. We claim that the task of discerning the difference between benign anomalies and those that represent an actual problem by an agent will increase its performance. Furthermore, we present a new definition of the term “problem” in a goal reasoning context. This paper discusses the role of explanations and goal formulation in response to developing problems and implements the response. The paper illustrates goal formulation in a mine clearance domain and a labor relations domain. We also show the empirical difference between a standard planning agent, an agent that detects anomalies and an agent that recognizes problems.