The Sensory Components of High-Capacity Iconic Memory and Visual Working Memory

Abstract

Early visual memory can be split into two primary components: a high-capacity, short-lived iconic memory followed by a limited-capacity visual working memory that can last many seconds. Whereas a large number of studies have investigated visual working memory for low-level sensory features, much research on iconic memory has used more “high-level” alphanumeric stimuli such as letters or numbers. These two forms of memory are typically examined separately, despite an intrinsic overlap in their characteristics. Here, we used a purely sensory paradigm to examine visual short-term memory for 10 homogeneous items of three different visual features (color, orientation and motion) across a range of durations from 0 to 6 s. We found that the amount of information stored in iconic memory is smaller for motion than for color or orientation. Performance declined exponentially with longer storage durations and reached chance levels after ∼2 s. Further experiments showed that performance for the 10 items at 1 s was contingent on unperturbed attentional resources. In addition, for orientation stimuli, performance was contingent on the location of stimuli in the visual field, especially for short cue delays. Overall, our results suggest a smooth transition between an automatic, high-capacity, feature-specific sensory-iconic memory, and an effortful “lower-capacity” visual working memory.

Action video game playing is associated with improved visual sensitivity, but not alterations in visual sensory memory

“…Percent correct were converted from four-alternative forced identification to d′ (a measure of sensitivity; Wickens, 2001). Next, to characterize the temporal properties of iconic memory, a one-phase exponential-decay function was fit to the d′ data using bestfit least squares method (Bradley & Pearson, 2012;Lu et al, 2005). This yielded three parameters; a 1 , the fast-decaying sensitivity that reflects the initial visual availability of stimulus information; τ, the time constant of the fast-decay sensitivity that represents the duration of iconic memory; and a 0 , the sensitivity at long delays that reflects the amount of information transferred into short-term memory without the benefit of cuing (see Lu et al, 2005).…”

“…As such, this task provides a continuous measure of memory retention at delays spanning from sensory (Coltheart, 1980) through short-term (Long, 1980) memory durations. Importantly, the time course and capacity of memory captured in the partial report task can be quantified through the psychometric modeling of three parameters that map onto the three possible mechanisms under consideration here: a 1 reflects the initial visual availability of stimulus information; τ indicates the decay rate and duration of sensory memory, thereby determining how much information is available for transfer into shortterm memory; and a 0 captures the amount of information that is retained in short-term memory (Bradley & Pearson, 2012;Graziano & Sigman, 2008;Kuhbandner, Spitzer, & Pekrun, 2011;Lu, Neuse, Madigan, & Dosher, 2005). By contrasting the persistence of visual information across these varying spans of memory retention, we are able to infer which mechanism(s) may underlie the broad differences observed between AVGPs and NVGPs.…”

Recognition of letters displayed as briefly flashed dot patterns

“…This provides compelling evidence that the persistence was being generated at the cortex rather than by retinal mechanisms. One might add that persistence of orientation information has been tested using cued discrimination (Bradley & Pearson, 2012), change detection (Sligte et al 2008), and flicker search (Rensink, 2014). Neuronal responses to orientation are first manifested in primary visual cortex and are most precise and vigorous at that site (Bair, 2005;Hubel & Wiesel, 1959;Snodderly & Gur, 1995).…”

The effect of black tea on human cognitive performance in a cognitive test battery

“…Visual search task is an established neuropsychological tool for testing the iconic memory [47,48]. It measures two parameters: the reaction time (RT) necessary to either detect or determine spatial location of the target.…”