ABSTRACT
The age of a case (in the CBR sense) is the amount of time that has elapsed between the time that the case originally occurred and the time of the current reasoning activity. People engaged in plausible reasoning tasks will, under appropriate circumstances, use the age of retrieved prior cases to filter and discard them, or to select among alternatives by their recency. This paper examines how the age of a case (and its spatial analog) are used by people in plausible and case-based reasoning tasks. I will argue that (1) The age of a retrieved case is an important factor in case relevance judgments for certain kinds of inferences. (2) When case age is relevant, more recent cases are usually, but not always, preferred to older ones (the “all other things being equal” caveat). Finally, I will argue that, somewhat surprisingly, (3) case age cannot be used as an index into memory given some commonly held assumptions about the nature of the retrieval process because it varies with the time of retrieval. This limits its use to post-retrieval processes, such as the filtering of already retrieved cases.
