Sensory Store Research Articles

A dynamic neural resource model bridges sensory and working memory

Probing memory of a complex visual image within a few hundred milliseconds after its disappearance reveals significantly greater fidelity of recall than if the probe is delayed by as little as a second. Classically interpreted, the former taps into a detailed but rapidly decaying visual sensory or ‘iconic’ memory (IM), while the latter relies on capacity-limited but comparatively stable visual working memory (VWM). While iconic decay and VWM capacity have been extensively studied independently, currently no single framework quantitatively accounts for the dynamics of memory fidelity over these time scales. Here, we extend a stationary neural population model of VWM with a temporal dimension, incorporating rapid sensory-driven accumulation of activity encoding each visual feature in memory, and a slower accumulation of internal error that causes memorized features to randomly drift over time. Instead of facilitating read-out from an independent sensory store, an early cue benefits recall by lifting the effective limit on VWM signal strength imposed when multiple items compete for representation, allowing memory for the cued item to be supplemented with information from the decaying sensory trace. Empirical measurements of human recall dynamics validate these predictions while excluding alternative model architectures. A key conclusion is that differences in capacity classically thought to distinguish IM and VWM are in fact contingent upon a single resource-limited WM store.

A dynamic neural resource model bridges sensory and working memory.

Probing memory of a complex visual image within a few hundred milliseconds after its disappearance reveals significantly greater fidelity of recall than if the probe is delayed by as little as a second. Classically interpreted, the former taps into a detailed but rapidly decaying visual sensory or 'iconic' memory (IM), while the latter relies on capacity-limited but comparatively stable visual working memory (VWM). While iconic decay and VWM capacity have been extensively studied independently, currently no single framework quantitatively accounts for the dynamics of memory fidelity over these time scales. Here, we extend a stationary neural population model of VWM with a temporal dimension, incorporating rapid sensory-driven accumulation of activity encoding each visual feature in memory, and a slower accumulation of internal error that causes memorized features to randomly drift over time. Instead of facilitating read-out from an independent sensory store, an early cue benefits recall by lifting the effective limit on VWM signal strength imposed when multiple items compete for representation, allowing memory for the cued item to be supplemented with information from the decaying sensory trace. Empirical measurements of human recall dynamics validate these predictions while excluding alternative model architectures. A key conclusion is that differences in capacity classically thought to distinguish IM and VWM are in fact contingent upon a single resource-limited WM store.

Attractive and facilitating store atmospheric stimuli

PurposeThe majority of past studies on the physical store environment have focused on the impacts of distinct store environmental cues like music, crowding and décor on consumers' responses. However, recent research posits that consumer is more likely to experience several cues in a combination, rather than in isolation, i.e. different categories of store environmental cues are likely to impact consumer psychology holistically. Hence, our study aims to identify the relevant factors of store atmospheric cues impacting consumer's attitude in physical retail store context and validate scales to measure such factors.Design/methodology/approachThis research develops and validates psychometrically reliable scales to measure two broad store stimuli factors namely: attractive and facilitating store stimuli, following the scale development method suggested by Churchill (1979).FindingsThe study shows that attractive store stimuli predict affective and sensory store brand experiences. The facilitating store stimuli moderate the effects of attractive store stimuli on affective and sensory store brand experiences. Affective and sensory store brand experiences predict store satisfaction.Originality/valueThis research contributes to the existing body of store ambience research by empirically understanding the psychological mechanism through which customers perceive different store cues holistically leading to the elicitation of store satisfaction.

A colorful advantage in iconic memory

Synesthesia is a benign neurodevelopmental condition in which stimulation of one sensory modality evokes experiences in a second, unstimulated modality (Simner and Hubbard, 2013). In grapheme-color synesthesia (GCS), which is experienced by 1–2% of adults, synesthetes reliably and involuntarily experience specific colors when viewing blackand-white graphemes. Previous case-studies have identified synesthetes with spectacular memory (Luria, 1968; Smilek, Dixon, Cudahy, & Merikle, 2001) and group studies have found advantages for synesthetes compared to nonsynesthetes in long-term memory (Rothen, Meier, & Ward, 2012). Here, we tested whether similar advantages are also present in earlier stages of memory. We tested visual iconic memory—the sensory store for vision—which has a very large capacity, but decays approximately 1000 ms after stimulus offset (Chow, 1985; Sergent et al., 2013; Sperling, 1960). We tested 20 synesthetes and 20 nonsynesthetes in a direct replication of the Sperling (1960) Partial Report Paradigm using letters (Experiment 1) and non-alphanumeric symbols (Experiment 2) as stimuli. Overall, synesthetes had a greater iconic memory capacity than nonsynesthetes when presented with synesthesia-inducing letter stimuli. This advantage was reduced when they were presented with non-synesthesia inducing symbol stimuli. Critically this advantage was most prominent when memory was stressed by asking participants to remember large arrays. Our results demonstrate that synesthetic memory advantages extend to the earliest stages of memory, and suggest that advantages in later stages of memory may arise from these earlier advantages.

Effects of priming visual relatedness and expectancy on visual search performance

Identifying and locating a target can be difficult when uncertainty exists about what to look for or even where to look. Cognitive research in matching and classification tasks (Neely, 1977; Posner & Snyder, 1975) have shown that uncertainty is reduced both by semantic priming, which is fast-acting but decays rapidly, and by expectancy, which has a slower onset but persists much longer. The current study extended their cognitive approach to a visual search paradigm in the perceptual-cognitive domain. We manipulated visual-relatedness between prime and target so that they were either identical (same) or different. We manipulated expectancy by varying the proportion of validly primed trials. The inter-stimulus interval (ISI) between offset of prime and onset of search display also was varied. Our goals were two-fold: (a) Does visual priming affect a brief sensory store that decays rapidly (e.g., Sperling, 1960) or a longer-lasting store, such as a visuo-sketchpad (Baddeley, 1993) or visual-implicit memory (Schacter & Cooper, 1993)? (b) Do the onsets of expectancy and priming occur simultaneously or does one precede the other? Twelve college-age subjects were tested and, at the beginning of the session, were informed of the prime's validity (20%, 50%, or 80%). They had to identify and locate the target within a brief visual search display of four objects. Response accuracy data indicated that the effects of visual priming decayed very rapidly, implying a sensory store mechanism rather than a visuo-spatial sketchpad or visual implicit memory. Moreover, visual priming effects occurred before the onset of expectancy.

Iconic Decay in Schizophrenia

Working memory impairment is considered a core deficit in schizophrenia, but the precise nature of this deficit has not been determined. Multiple lines of evidence implicate deficits at the encoding stage. During encoding, information is held in a precategorical sensory store termed iconic memory, a literal image of the stimulus with high capacity but rapid decay. Pathologically increased iconic decay could reduce the number of items that can be transferred into working memory before the information is lost and could thus contribute to the working memory deficit seen in the illness. The current study used a partial report procedure to test the hypothesis that patients with schizophrenia (n = 37) display faster iconic memory decay than matched healthy control participants (n = 28). Six letters, arranged in a circle, were presented for 50 ms. Following a variable delay of 0-1000 ms, a central arrow cue indicated the item to be reported. In both patients and control subjects, recall accuracy decreased with increasing cue delay, reflecting decay of the iconic representation of the stimulus array. Patients displayed impaired memory performance across all cue delays, consistent with an impairment in working memory, but the rate of iconic memory decay did not differ between patients and controls. This provides clear evidence against faster loss of iconic memory representations in schizophrenia, ruling out iconic decay as an underlying source of the working memory impairment in this population. Thus, iconic decay rate can be added to a growing list of unimpaired cognitive building blocks in schizophrenia.

The panmodal sensory imprecision hypothesis of schizophrenia: reduced auditory precision in schizotypy

Research on tasks such as pitch discrimination suggests the presence of a panmodal sensory imprecision in schizophrenia: a global deficit in the fidelity of representations. In order to better understand the basis of this deficit, auditory precision was examined in a normal sample varying in schizotypal personality disorder (SPD) symptoms. Experiment 1 reports a significant linear relationship between auditory imprecision and SPD scores. A second experiment on the effects of delay revealed that, as in schizophrenia, this deficit did not reflect an increased rate of decay of the representation. A third experiment used an auditory inspection time task to examine speed of processing using a backward mask to limit exposure duration. No differences in processing speed were found. These results mirror findings in schizophrenia and suggest that the rate of information accumulation into the sensory store is normal, as is the rate of decay of this representation, but that the ultimate fidelity of primary sensory representations is reduced. It is suggested that deficits in the fine structure of representations may be a basic element of vulnerability for schizophrenia.

The internal auditory clock: what can evoked potentials reveal about the analysis of temporal sound patterns, and abnormal states of consciousness?

Whereas in vision a large amount of information may in theory be extracted from instantaneous images, sound exists only in its temporal extent, and most of its information is contained in the pattern of changes over time. The “echoic memory” is a pre-attentive auditory sensory store in which sounds are apparently retained in full temporal detail for a period of a few seconds. From the long-latency auditory evoked potentials to spectro-temporal modulation of complex harmonic tones, at least two automatic sound analysis processes can be identified whose time constants suggest participation of the echoic memory. When a steady tone changes its pitch or timbre, “change-type” CP1, CN1 and CP2 potentials are maximally recorded near the vertex. These potentials appear to reflect a process concerned with the distribution of sound energy across the frequency spectrum. When, on the other hand, changes occur in the temporal pattern of tones (in which individual pitch changes are occurring at a rate sufficiently rapid for the C-potentials to be refractory), a large mismatch negativity (or MN1) and following positivity (MP2) are generated. The amplitude of these potentials is influenced by the degree of regularity of the pattern, larger responses being generated to a “deviant” tone when the pitch and time of occurrence of the “standards” are fully specified by the preceding pattern. At the sudden cessation of changes, on resumption of a steady pitch, a mismatch response is generated whose latency is determined with high precision (in the order of a few milliseconds) by the anticipated time of the next change, which did not in fact occur. The mismatch process, therefore, functions as a spectro-temporal auditory pattern analyser, whose consequences are manifested each time the pattern changes. Since calibration of the passage of time is essential for all conscious and subconscious behaviour, is it possible that some states of unconsciousness may be directly due to disruption of internal “clocks”? Abnormal mismatch potentials may provide a manifestation of a disordered auditory time-sense, sometimes being abolished in comatose patients while the C-potentials and similar responses to the onset of tones are preserved. Both C- and M-potentials were usually found to be preserved, however, in patients who had emerged from coma and were capable of discriminating sounds. Substantially intact responses were also recorded from three patients who were functionally in a “vegetative” state. The C- and M-potentials were once again dissociated in a group of patients with multiple sclerosis, only the mismatch potentials being found to be significantly delayed. This subclinical impairment of a memory-based process responsible for the detection of change in temporal sound patterns may be related to defects in other memory domains such as working memory.

Perceptual organization in schizophrenia: the processing of symmetrical configurations.

The hypothesis that the perceptual organization dysfunction of patients with poor premorbid schizophrenia is due to a deficit in global visual sensory store processing was tested by assessing their ability to process symmetrical configurations that develop early and have strong prepotent structures. Two same-different judgment tasks in which performance varies as a function of the symmetrical organization and task demands were administered to participants with good and poor premorbid schizophrenia, those with mood disorders, and normal controls. Like the other groups, poor premorbid schizophrenics' latency and error response patterns closely paralled the a priori model of adequate processing. The results support their competence in perceptually processing symmetrical configurations and disconfirm the hypothesis that their input deficiencies represent a general deficiency in all forms of perceptual organization. The implications for specifying their early input dysfunction are discussed.

Dot Enumeration Perceptual Organization Task (DEPOT): evidence for a short-term visual memory deficit in schizophrenia.

The Dot Enumeration Perceptual Organization Task (DEPOT) evaluates the validity of 2 specific competing cognitive models of early input dysfunction in schizophrenic individuals: a primary Stage 1, sensory store, perceptual organization deficit vs. a Stage 2, short-term visual memory (STVM) deficit. DEPOT was also designed to assess the hypothesis that schizophrenic individuals tend to perform poorly on all cognitive tasks. In DEPOT both number and form judgments are made about the same dot patterns. A response delay manipulation assesses the persistence and operation of STVM. The study included 41 psychotic inpatients (8 with acute and 16 with chronic schizophrenia and 7 with bipolar and 10 with nonbipolar affective disorder) and 38 controls (22 college students and 16 hospital personnel). Although the pattern of results was consistent with neither the Stage 1 deficit nor the general deficit hypotheses, a Stage 2, STVM deficit hypothesis could account parsimoniously for the data.

Application of signal detection methodology to a critical stimulus duration procedure: Evidence of a visual sensory store deficit among hypothetical schizotypals

The present study was an investigation of the ability of a traditional critical stimulus duration (CSD) procedure to equate schizophrenia spectrum and control subjects on visual initial input capacities. The original MMPI was administered to college students from a nonclinical setting. The 2-7-8 profile type was used in identifying the hypothetically schizotypal population ( n = 12). Subjects producing an inflation free ( n = 12) or a 4-9 ( n = 12) MMPI code constituted the control groups. Analyses of CSD values using the commonly employed yes-no forced choice procedure revealed no significant differences among groups. A yes-no signal detection procedure was employed in constructing receiver operating characteristic curves for each individual's CSD. Transformed sensitivity and response bias analyses revealed that the 2-7-8 group demonstrated significantly lower visual sensitivity in comparison to the control groups. A less clear pattern of response bias differences was also obtained. These results are discussed in terms of the validity of commonly employed CSD procedures and the need for applied signal detection analyses in at-risk research.

AEPs at the onset and offset of repetitive sound modulation, due to mismatch with the contents of an auditory sensory store

Long latency auditory evoked potentials (AEPs), chiefly consisting of a negative peak at about 150 msec and a positivity at 250 msec, were recorded at the beginning and end of periods during which the interaural time difference of binaural noise was switched between 0.0 and 0.8 msec at a fast rate (ISI = 50 or 25 msec) or the frequency of continuous binaural clicks was switched between 167 and 200 Hz every 80, 50 or 25 msec. In the latter case the offset responses occurred later than onset by a mean of 89, 47 and 27 msec respectively, suggesting they were probably generated at the moment the next switch was expected but failed to occur. The offset responses must be non-specific with respect to the interaural delay or the frequency of clicks, since neurones which respond to particular delays or frequencies and are made refractory by a rapid rate of stimulation should not suddenly become less so at the last in a series of identical stimuli, or be activated by the absence of a further event. It is proposed that the potentials are due to a higher order of neurone which automatically responds to the occurrence of a “mismatch” between the immediate sound and an image of that which was previously present, encoded in a short-term sensory store. In addition to frequency content and interaural delay, the image must contain information about the temporal modulation pattern of the sound over the previous few seconds.

The sensory basis of mind: Feasibility and functionality of a phonetic sensory store

The sensory basis of mind: Feasibility and functionality of a phonetic sensory store

Forward recognition masking: Another look at the “Echo”

Auditory backward recognition masking effects have been interpreted as reflecting the existence of an echoic memory: an unencoded sensory store whose contents decay rapidly and are easily overwritten by succeeding auditory stimulation. However, it is equally likely that masking effects reflect the time course of an early stage of auditory processing. To distinguish these alternative conceptualizations, vowel stimuli were used in a forward recognition masking procedure. The interstimulus interval (ISI) remained constant, while the mask duration (and hence the stimulus-onset asynchrony, SOA) was varied. The simple storage model predicts that the efficacy of a mask is a function of the time between mask offset and target onset (ISI). Since this interval was constant, equal masking effects would be expected at all SOA intervals. The perceptual processing view predicts that target recognition performance would improve with increasing mask duration (increasing SOA). As mask duration/SOA increases, it is likely that processing of the mask would be completed before target onset. The results, and the implications of these findings, will be discussed. [Work supported by NINCDS.]

Auditory sensory storage in relation to the growth of sensation and acoustic information extraction.

A brief, vivid phase of auditory sensory storage that outlasts the stimulus could be used in perception in two ways: First, all of the neural activity resulting from the stimulus, including that of the sensory store, could contribute to a sensation of growing loudness; second, the sensory store could permit the continued extraction of information about the sound's acoustic properties. This study includes a task for which these two processes lead to different predictions; a third prediction is based on the two processes combined. The task required loudness judgments for two brief tones presented with a variable intertone interval. The results of Experiments 1-3 were as one would expect if both the growth of sensation and information extraction contributed to the pattern of loudness judgments. Experiment 4 strengthened the two-process account by demonstrating the separability of the two processes. Approaches to mathematical modeling of these results are discussed.

Amodal completion: Simplicity is not the explanation

Six experiments were performed to investigate factors that might influence the use of symmetry versus good continuation in the completion of a partially occluded shape. With 1-sec presentations, subjects used good continuation on 74.6% of the trials and were not influenced by manipulations designed to draw their attention to different aspects of the shapes. With a 9-sec presentation, good continuation completions dropped to 37% and symmetric completions rose to 53.2%. The results suggest a precedence effect with naive subjects. Features favoring completion through good continuation (e.g., lines at points of intersection) are read out of a sensory store more quickly than are features favoring completion through symmetry (e.g., symmetrically opposite comers). Showing only selected parts of the stimulus through holes in a mask influenced subjects’ responses. The results suggest that completion is not based on the simplicity of the completed shape, but rather is determined by the parts of the stimulus that are processed.

Neurobehavioural effects of occupational exposure to lead.

A set of neurobehavioural tests selected on the basis of information processing theory was used to study the effect of low level occupational lead exposure on 59 lead workers compared with a matched control group of the same number. Only one of the lead exposed group had a blood lead concentration above the current threshold limit value of 3.81 mumol/l at the time of testing (mean 2.36 mumol/l, range 1.19-3.92 mumol/l) and none had been detected above that level in the previous three years. Nevertheless, most neurobehavioural functions tested showed some impairment in the lead workers. Visual sensory function was affected and, perhaps as a consequence, sustained attention and psychomotor tasks were performed more slowly by the lead exposed group. Cognitive functions were also impaired, with sensory store memory, short term memory, and learning abilities all showing deficits in lead workers. Such cognitive deficits may also be partly due to initial degradation of the visual input. Long term memory performance compared equally with control levels possibly because of development of a compensatory strategy such as rehearsal by the lead exposed subjects. Multiple linear regression analysis relating to lead workers test performance and their lead exposure showed that performance on the sensory store memory test alone was significantly related to exposure. This was probably due to the homogeneity of the lead exposed group with regard to blood lead concentrations and the use of blood lead as a measure of chronic lead exposure.

Rapid, permanent, loss of memory for absolute intensity of taste and smell

Memory formation for the absolute intensity of taste and smell was investigated in a series of experiments. In Experiment 1, 336 subjects tasted 10 ml of 15% sucrose and were asked to remember the strength of the solution. They were retested with 5%, 10%, 15%, or 20% sucrose, at one of four delay intervals (1, 5, or 15 min, or 72 h). They compared the second stimulus with the first stimulus and reported whether the second was “less sweet, ” “the same, ” or “sweeter. ” Subjects reliably reported that 5% sucrose was less sweet and that 20% sucrose was sweeter. However, when the second stimulus was 15% sucrose (i.e., was equal to the standard), approximately 60% of the subjects reported that it was sweeter, regardless of the delay interval between the two stimuli. About 2/3 of those tasting 10% sucrose reported that it was as sweet as or sweeter than the 15% standard. A similar finding from a procedure using magnitude estimation was reported in Experiment 2. The same pattern of results was also found for an olfactory memory test (Experiment 3). When asked to match either a 1.33- or a 5.0-ppm pyridine olfactory stimulus, subjects consistently picked a concentration weaker than the standard. Apparently, olfactory and taste stimuli are remembered as being substantially weaker as soon as the memory for these stimuli can be tested. A memory model that posits a sensory store within which a taste or smell stimulus of a given intensity rapidly fades to a lower level of intensity is suggested. The new memory is then relatively unchanged for at least 3 days.

Perceived principal pitch of vibrato tones.

When we listen to vibrato tones, we perceive not only frequency fluctuation but also somewhat steady pitch. This pitch sensation of vibrato tones is defined as “principal pitch.” The principal pitch of vibrato tones is located around its carrier frequency, by a method of adjustment. As the location of principal pitch of vibrato tones has the width proportional to its extent of frequency changing, it is impossible to be located more precisely. The principal pitch of symmetrical trill tones is located around its carrier frequency, too. The location of principal pitch of asymmetrical trill tones is shifted in the direction of the longer one between high frequency interval and low frequency interval. This means that the location of principal pitch of frequency modulated tones is defined not only by higher and lower extremes of modulation extent but also by the whole process of frequency changing. It is more shifted than the simple time average of frequency changing. From these experimental results we suppose the pitch averaging mechanism in the auditory process to perceive principal pitch of frequency modulated tones. In this process, this mechanism samples pitch changing continuously, registers in sensory store, and averages every certain moment. When a pitch distribution of frequency modulated tones is asymmetrical, this mechanism accomplishes its function after emphasizing the large part of the distributio.

Developmental differences in cognitive scanning and encoding of visual information

Report accuracy of horizontally arranged letter sequences was measured for second-grade children and adults using a tachistoscopic single report procedure. Results indicated age differences in both the amount of information encoded out of visual sensory store and in the magnitude of left-right visual field differences. However, large age differences in amount of encoded information were also present under conditions which served to reduce left-right visual-field asymmetries in report accuracy. These findings are discussed in terms of their implications for using a left-to-right cognitive trace scanning explanation to account for age differences in encoding efficiency.