The Three "Ws" of Episodic Memory: What, When, and Where

At its core, episodic memory requires the encoding and retention of occurrence information. One needs to remember that a particular item occurred (what) at a particular time (when) in a particular place (where). These task requirements are scale independent, meaning that they hold regardless of whether one is asked to remember over the short or the long-term. In the present article, written to honor the contributions of Alice Healy, I review evidence suggesting that the benchmark phenomena of short-term memory, including bow-shaped serial position curves, symmetric error gradients, and even our limited memory span, actually arise from processes associated with the recovery of occurrence information. Rather than reflecting the properties of a special short-term storage system, these signature empirical patterns are characteristic of remembering over almost any time scale. More generally, I argue that occurrence information can be conceptualized as stored values along largely independent temporal and spatial dimensions. Such a framework provides a useful way of distinguishing between item and order information, although I conclude by suggesting that item memory requires more than simply the recovery of occurrence. Mnemonic representations, once accessed, must be interpreted or "recovered" as well.