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.