Effects of stimulus familiarity upon judged visual duration

Expectation, information processing, and subjective duration

In research on psychological time, it is important to examine the subjective duration of entire stimulus sequences, such as those produced by music (Teki, Frontiers in Neuroscience, 10, 2016). Yet research on the temporal oddball illusion (according to which oddball stimuli seem longer than standard stimuli of the same duration) has examined only the subjective duration of single events contained within sequences, not the subjective duration of sequences themselves. Does the finding that oddballs seem longer than standards translate to entire sequences, such that entire sequences that contain oddballs seem longer than those that do not? Is this potential translation influenced by the mode of information processing-whether people are engaged in direct or indirect temporal processing? Two experiments aimed to answer both questions using different manipulations of information processing. In both experiments, musical sequences either did or did not contain oddballs (auditory sliding tones). To manipulate information processing, we varied the task (Experiment 1), the sequence event structure (Experiments 1 and 2), and the sequence familiarity (Experiment 2) independently within subjects. Overall, in both experiments, the sequences that contained oddballs seemed shorter than those that did not when people were engaged in direct temporal processing, but longer when people were engaged in indirect temporal processing. These findings support the dual-process contingency model of time estimation (Zakay, Attention, Perception & Psychophysics, 54, 656-664, 1993). Theoretical implications for attention-based and memory-based models of time estimation, the pacemaker accumulator and coding efficiency hypotheses of time perception, and dynamic attending theory are discussed.

Sub-Second Temporal Integration of Vibro-Tactile Stimuli: Intervals between Adjacent, Weak, and Within-Channel Stimuli Are Underestimated

Tactile estimation of sub-second time is essential for correct recognition of sensory inputs and dexterous manipulation of objects. Despite our intuitive understanding that time is robustly estimated in any situation, tactile sub-second time is altered by, for example, body movement, similar to how visual time is modulated by eye movement. The effects of simpler factors, such as stimulus location, intensity, and frequency, have also been reported in temporal tasks in other modalities, but their effects on tactile sub-second interval estimation remain obscure. Here, we were interested in whether a perceived short interval presented by tactile stimuli is altered only by changing stimulus features. The perceived interval between a pair of stimuli presented on the same finger apparently became short relative to that on different fingers; that of a weak-intensity pair relative to that of a pair with stronger intensity was decreased; and that of a pair with the same frequency relative to one with different frequencies was underestimated. These findings can be ascribed to errors in encoding temporal relationships: nearby-space/weak-intensity/similar-frequency stimuli presented within a short time difference are likely to be integrated into a single event and lead to relative time compression.

Feature-based attention influences later temporal perception

We investigated the influence of feature-based visual attention on later temporal perception. Although there is ample evidence that space-based attention modulates temporal perception, it is not known whether feature-based attention also serves this function. The present study combined a visual selection task with a temporal interval production task to determine whether feature-based attention interacted with temporal perception. The results indicated that temporal perception of visual stimuli depended on whether the same stimulus had been attended to or ignored in a previous visual selection task. The temporal production of previously ignored stimuli was longer than the temporal production of either previously attended to or novel stimuli. This is the first demonstration of the effect of feature-based attention on later temporal perception. We concluded that temporal perception is affected by previously ignored stimuli.

Attention and the subjective expansion of time

During brief, dangerous events, such as car accidents and robberies, many people report that events seem to pass in slow motion, as if time had slowed down. We have measured a similar, although less dramatic, effect in response to unexpected, nonthreatening events. We attribute the subjective expansion of time to the engagement of attention and its influence on the amount of perceptual information processed. We term the effect time's subjective expansion (TSE) and examine here the objective temporal dynamics of these distortions. When a series of stimuli are shown in succession, the low-probability oddball stimulus in the series tends to last subjectively longer than the high-probability stimulus even when they last the same objective duration. In particular, (1) there is a latency of at least 120 msec between stimulus onset and the onset of TSE, which may be preceded by subjective temporal contraction; (2) there is a peak in TSE at which subjective time is particularly distorted at a latency of 225 msec after stimulus onset; and (3) the temporal dynamics of TSE are approximately the same in the visual and the auditory domains. Two control experiments (in which the methods of magnitude estimation and stimulus reproduction were used) replicated the temporal dynamics of TSE revealed by the method of constant stimuli, although the initial peak was not apparent with these methods. In addition, a third, control experiment (in which the method of single stimuli was used) showed that TSE in the visual domain can occur because of semantic novelty, rather than image novelty per se. Overall, the results support the view that attentional orienting underlies distortions in perceived duration.

Judgments of duration, figure-ground contrast, and size for words and nonwords

Does the word-superiority effect on letter discrimination result in a word-superiority effect on duration judgments? We examined this question in five experiments. In the first four experiments, we have demonstrated that (1) words shown for 32-80 msec were judged as presented longer than non-words shown for the same duration; (2) this word-superiority effect persists if the stimuli are shown for an objective duration of up to 250 msec; and (3) these effects can be extended to judgments of figure-ground contrast and letter size. These findings extend existing data on effects of processing fluency on perceptual judgments. In Experiment 5, we found that duration judgments were higher for words than for pronounceable nonwords, and duration judgments were higher for pronounceable non-words than for nonpronounceable nonwords. We discuss the implications of this finding for the discrepancy-attribution hypothesis.

Effects of interval duration on temporal processing in schizophrenia

INTRODUCTION

Temporal processing has received scant attention in the literature pertaining to cognitive deficits in patients with schizophrenia. Previous research suggests that patients with schizophrenia exhibit temporal perception deficits on both auditory and visual stimuli. The current study investigated the effects of interval manipulation to (1) replicate the original findings with a larger sample and an increased number of trials (2) assess the degree to which both patients and controls can differentiate temporal changes in a range of experimental interstimulus intervals, and (3) explore whether different interstimulus interval durations pose different levels of difficulty for the patients with schizophrenia.

METHODS

Participants were asked to decide whether temporal intervals were shorter or longer than standard intervals on a computer-based auditory temporal perception task. The standard interval remained the same duration throughout the various tasks. The interstimulus interval separating the standard and experimental intervals varied in the range of 500, 1000, or 3000 ms. Data are presented for a sample of 16 patients with schizophrenia and 15 controls.

RESULTS

Data suggest that patients with schizophrenia exhibit deficits in differentiating interval durations across all paradigms compared to their control-group peers on a range of auditory tasks (p<.001).

CONCLUSIONS

These results are consistent with a general temporal deficit in schizophrenia. However, the roles of medication and localization are also addressed.

Functional localization of a "Time Keeper" function separate from attentional resources and task strategy

The functional neuroanatomy of time estimation has not been well-documented. This research investigated the fMRI measured brain response to an explicit, prospective time interval production (TIP) task. The study tested for the presence of brain activity reflecting a primary time keeper function, distinct from the brain systems involved either in conscious strategies to monitor time or attentional resource and other cognitive processes to accomplish the task. In the TIP task participants were given a time interval and asked to indicate when it elapsed. Two control tasks (counting forwards, backwards) were administered, in addition to a dual task format of the TIP task. Whole brain images were collected at 1.5 Tesla. Analyses (n = 6) yielded a statistical parametric map (SPM ¿z¿) reflecting time keeping and not strategy (counting, number manipulation) or attention resource utilization. Additional SPM ¿z¿s involving activation associated with the accuracy and magnitude the of time estimation response are presented. Results revealed lateral cerebellar and inferior temporal lobe activation were associated with primary time keeping. Behavioral data provided evidence that the procedures for the explicit time judgements did not occur automatically and utilized controlled processes. Activation sites associated with accuracy, magnitude, and the dual task provided indications of the other structures involved in time estimation that implemented task components related to controlled processing. The data are consistent with prior proposals that the cerebellum is a repository of codes for time processing, but also implicate temporal lobe structures for this type of time estimation task.

Visual processing of verbal and nonverbal stimuli in adolescents with reading disabilities

This study investigated whether a group of children with reading disabilities (RD) were slower at processing visual information in general (compared to a group of children of comparable age and a group of children of comparable reading level), or whether their deficit was specific to the written word. Computerized backward masking and temporal integration tasks were used to assess the speed of visual information processing. Stimulus complexity (simple, complex) and type (verbal, nonverbal) were varied, creating a 2 x 2 matrix of stimulus conditions: simple nonverbal, complex nonverbal, simple verbal, and complex verbal. Adolescents with RD demonstrated difficulties in processing rapidly presented verbal and nonverbal visual stimuli, although the effect was magnified when they were processing verbal stimuli. Thus, the results of this study suggest that some youth with reading disabilities have visual temporal processing deficits that compound difficulties in processing verbal information during reading.

On the left and right hemisphere visual processing that precedes recognition

Three experiments, and a replication of each, investigated the nonconscious prerecognition visual processing given left visual field (LVF) and right visual field (RVF) letter inputs. Each input was a vertically arrayed pair of letters in which three variables were manipulated: (1) the same letter twice vs one each of two letters, (2) same vs 180 degree difference in orientations within each letter pair, and (3) normal vs mirror-image letter form. The procedure presented all pairs of letter combinations in pairs of pre- and postmasked 10-msec flashes; the subject's task was to report which flash of each pair appeared to last longer. When letter pairs differed on all three variables, RVF presentations of mirror-image letters were judged to be longer than equal presentations of normal letters; the reverse occurred for LVF presentations. When one normal and mirror-image letter were presented, RVF presentations of mismatched orientations were judged to be longer than matched orientations, and the reverse was true for LVF presentations. When pairs of two normal letters were presented, no processing difference between LVF and RVF presentations was observed. A fourth experiment tested presence/absence detection of the letter pairs under the input conditions of the main experiments and showed those conditions to produce chance-level presence/absence detection. These results suggest that each hemisphere can perform its own prerecognition operations and that neither hemisphere is necessarily specialized for any particular prerecognition visual operation.

Apparent duration and spatial structure

In three experiments, we investigated the relative perceived duration of a full bandwidth image and a set of high- and lowpass filtered images of a scene, briefly presented on a visual display unit. In Experiment 1, the various images were compared with each other, using a paired comparison method. All images were presented for 40 msec, and observers were asked to judge which of each pair of images had the longest duration. The results showed that images containing a wide spatial frequency bandwidth were judged to be of longer duration than were images of a narrower bandwidth, regardless of whether the latter were high- or lowpass filtered. In Experiment 2, a 40-msec presentation of each of the images was compared with a presentation of a probe that was 20, 40, 60, or 80 msec in duration. Observers again judged which of each pair of images had the longest duration. The results were very similar to those of Experiment 1, with wide bandwidth images being judged to be of longer duration than were narrow bandwidth images. In Experiment 3, instead of comparing the various filtered versions of the image with each other, we attempted to obtain a direct measure of perceived duration by comparing a flashing LED to a 40-msec flash of a subset of the images used in the previous experiments. The observers' task was to adjust the duration of the LED flash to match the perceived duration of each image.(ABSTRACT TRUNCATED AT 250 WORDS)

Duration discrimination of filled and empty auditory intervals: cognitive and perceptual factors

Adult subjects were presented with two auditory stimuli per trial, and their task was to decide which of the two was longer in duration. An adaptive psychophysical procedure was used. In Experiments 1, 2, and 4, the base duration was 50 msec, whereas in Experiment 3, the base duration was 1 sec. In Experiments 1, 2, and 4, it was found that filled intervals (continuous tones) were discriminated more accurately than empty intervals (with onset and offset marked by clicks). It was concluded that this difference was perceptual rather than cognitive in nature, since performance on filled and empty intervals was not affected by increasing cognitive load in a dual-task procedure (Experiment 2) but was affected by backward masking (Experiment 4). In contrast, the results of Experiment 3 showed that duration discrimination of filled auditory intervals of longer duration was cognitively influenced, since performance was impaired by increasing cognitive load. Implications for notions of perceptual processing and timing mechanism underlying differences in duration discrimination with filled and empty intervals are discussed.

Duration of visible persistence in relation to stimulus complexity

Visible persistence refers to the phenomenal impression that a stimulus is still present after its offset. A dispute exists whether visible persistence is due to temporal sluggishness in the visual pathway (neural hypothesis) or whether it is a byproduct of information-extraction processes under cognitive control (process hypothesis). This was investigated by manipulating stimulus complexity in five temporal integration experiments and one recognition memory experiment. According to the process hypothesis, complex stimuli should persist longer than simple stimuli because they require more information extraction. This prediction was not confirmed; in all six experiments, complexity was found to have no reliable effect on the duration of visible persistence. By contrast, and in accordance with earlier findings, complexity was shown to have a significant effect on a short-lived, nonvisible form of memory known as schematic persistenc. This pattern of results supports two major conclusions: First, that the effects of complexity reported in earlier research were probably on schematic--rather than visible--persistence; and second, that visible persistence must be regarded as a residual neural trace of an extinguished stimulus, rather than as a byproduct of information-extraction processes.

A model of empty duration perception

An attempt to construct a general theory of duration perception is presented. First, four experiments are reported in which the supplement hypothesis, on the relation between two or three empty durations, was examined: the subjective duration of a subjectively empty time interval is directly proportional to its physical duration plus a constant of approximately 80 ms. This hypothesis could be applied to the ratio judgments of auditorily marked empty durations between 40 and 600 ms given serially. It could also explain the discrepancies between musically notated rhythms and the corresponding physical performed rhythms in very simple rhythm patterns consisting of three tones. Next, three earlier experiments on discriminations of empty durations marked by sound bursts were also reanalyzed. Within the range 40-600 ms, the absolute just noticeable difference of an empty duration was almost directly proportional to the standard duration plus a constant of about 80 ms. If the supplement hypothesis is accepted, this means that the relative just noticeable difference of the subjective duration was constant. Finally, the processing time hypothesis is presented: subjective duration is directly proportional to the physical time required to process the given empty duration. This processing is considered to begin with the detection of the first marker, and to end approximately 80 ms after the detection of the second marker.

Growth of apparent duration: effect of melodic and non-melodic tonal variation

Time estimates of 12 intervals of 15 to 65 sec. duration were obtained from 30 subjects by one of two methods, magnitude estimation and cross-modal matching. Three kinds of sequences of musical notes were presented during stimulus intervals; repetitive, melodic, and random. Within all sequences, notes were of equal duration and with equal pauses between them. In all cases, the relationship between perceived and physical time is consistent with Stevens' power law. Exponents derived from both kinds of estimates were significantly affected by the content of the interval. Exponents derived for repetitive sequences were not different from 1 and were significantly larger than exponents derived from random or melodic sequences. These results are inconsistent with the view that the predictability, familiarity, or codability of event occurring in the stimulus interval is inversely related to the perceived duration of that interval. There is some indication that the effect of the content of the interval on judgments of duration varies with the magnitude of the duration being judged. Perhaps the relationship holds only within certain parameters and, when these are exceeded, other factors mask the effect. A two-process theory of time perception, one which considers these other factors and explains the present results, is proposed.

Development of information processing in normal and disabled readers

8- and 11-yr-old reading-disabled children were compared in two experiments with controls matched on intelligence and age. Exp. 1 measured duration of visual information store by means of a separation threshold technique. Exp. II determined the rate of transfer from visual information store to short-term memory using a backward masking technique. Results from Exp. I showed that at each age specific reading-disabled children had significantly longer durations of visual information store than controls. The difference between the reading ability groups decreased with increasing age. Exp. II demonstrated that rate of transfer of information was significantly slower for specific reading-disabled children than for controls at both age levels. In contrast to Exp. I, this difference increased with increasing age. The results are considered in terms of their possible relevance to developmental lag theories. The evidence indicates that the development of visual information processing in reading-disabled children is similar to that in controls but occurs at a slower rate.

Time Estimation and Reproduction under Conditions of Differential Perceptual Oscillation

Experienced duration was measured by the methods of reproduction and estimation under two conditions of perceptual oscillation, binocular rivalry and figure-ground reversal. While the number of rivalries was significantly negatively correlated with both reproduced and estimated time, the number of figure reversals was not correlated with judgments of duration. For both conditions of perceptual oscillation, reproduced and estimated durations were significantly positively correlated.