We describe a theory of memory for visual material in which the visual system acts as a linear filter operating on a stimulus to produce a function, a(t), relating some sensory response to t (the time since stimulus onset). Stimulus information is acquired at a rate proportional to the product of the magnitude by which a(t) exceeds some threshold, and the amount of as-yet-unacquired information. Recall performance is assumed to equal the proportion of acquired information. The theory accounts for data from 2 digit-recall experiments in which stimulus temporal waveform was manipulated. We comment on the theory's account of the relation between 2 perceptual events: the phenomenological experience of the stimulus, and the memory representation that accrues from stimulus presentation. We assert that these 2 events, although influenced by different variables, can be viewed as resulting from 2 characteristics of the same sensory-response function.