A theory of visual information acquisition and visual memory with special application to intensity-duration trade-offs.

Abstract

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.In this article, we discuss the perception of and memory for complex visual stimuli. By complex we mean stimuli (such as alphanumeric characters, words, or naturalistic scenes) that must be pattern-recognized, interpreted, and processed by the cognitive system rather than simple, to-bedetected light patches or sine-wave gratings. Our major goal is to incorporate a model that has been successfully used to account for a variety of low-level visual phenomena (e.g., time-intensity trade-offs and flicker perception) into a broader theory designed to account for higher level cognitive tasks such as recall and picture recognition.Our theory development is motivated in part by the substantial body of research implying intimate perceptual connections between stimulus duration on the one hand and stimulus intensity on the other. Before describing the theory we provide a brief sketch of this research and describe an experiment designed to relate it to memory for visual material.

How Different Spatial-Frequency Components Contribute to Visual Information Acquisition.

“…To do so, they fit to their data a theory called the sensory response-information acquisition (SRIA) theory, which is an instance of what we have defined to be an independence theory: The order of spatial-frequency components does not matter, and the spatial-frequency components combine additively. The SRIA theory has been described in detail elsewhere as it applies to perception and memory of digit strings (Busey & Loftus, 1994Loftus, Busey, & Senders, 1993;Loftus & Ruthruff, 1994); line drawings (Loftus & McLean, 1999); and random forms (Harley, Dillon, & Loftus, 2003). To understand the meaning of Olds and Engel's results, it is necessary to understand this theory, so we describe it here briefly.…”

Metamers in the haptic perception of heaviness and moveableness

“…In an inquiry into Bloch's law (tradeoff in vision between intensity and duration with respect to threshold-detection performance), Loftus and Ruthruff (1994) highlighted the idea that metamerism can be of more than one form and of more than one origin. As Backus (2002) has suggested, Loftus and Ruthruff hinted at the possibility of a hierarchy of metamers with levels defined by the descriptions under which two physically different stimuli were indistinguishable.…”

“…Two or more stimuli with the same value of duration ϫ intensity are only perceptual metamers (manifest at the time of viewing) up to a limiting duration, but they can be memory metamers (equivalent to recall performance subsequent to viewing) at any duration. For the sensoryresponse functions of equal-product stimuli, sameness in shape yields perceptual metamers, and sameness in area yields memory metamers (Loftus & Ruthruff, 1994). …”

Temporal inhibition in character identification

“…The nature of this sensory response function has previously been shown to be important for models of detection (Sperling & Sondhi, 1968;Watson, 1986), intensityduration tradeoffs in information processing tasks (Loftus & Ruthruff, 1994), metacontrast masking (Breitmeyer, This research was funded in part by an NIMH predoctoral grant to T.A.B. and NINH Grant MH4l637 to Geoffrey R. Loftus.…”

“…It has long been known that the response to a stimulus outlasts its offset (see Coltheart, 1980, for an excellent review), and the characteristics of this initial sensory response reflect this fact. All subsequent visual processing is based on this initial representation, and thus the first step in characterizing the mechanisms that underlie object or character identification must address the nature of this initial sensory representation.The nature of this sensory response function has previously been shown to be important for models of detection (Sperling & Sondhi, 1968;Watson, 1986), intensityduration tradeoffs in information processing tasks (Loftus & Ruthruff, 1994), metacontrast masking (Breitmeyer, This research was funded in part by an NIMH predoctoral grant to T.A.B. and NINH Grant MH4l637 to Geoffrey R. Loftus.…”