Ordinal properties of perceived average duration: simultaneous and sequential presentations

When a subject evaluates the duration of two simultaneous events, the perceived durations are combined in a nonlinear manner, whereas comparable evaluations of successive events yield linear combinations. Fifty-four subjects rated average durations of pairs of time intervals ranging from 0.5 s to 10.0 s. The intervals making up a pair were presented successively and simultaneously on separate occasions within the same presentation sequence. The order of data was consistent with models previously proposed for perceived average duration. A nonmetric analysis of the combined ordinal data from both conditions yielded a single set of measures of perceived duration with ratio-scale properties. The common scale for the two conditions is consistent with differences in results from simultaneous and successive monitoring of time intervals, stemming from differences in the way duration information is combined rather than how it is perceived. the derived scale is related to physical time by a power function with a 1.06 exponent.     

Transient spatial attention and the perceived duration of brief visual events

This study was designed to explore the effects of transient attention—the stimulus-driven component of spatial attention—on the perceived duration of a brief visual event. Observers had to compare the duration of two disks presented successively within a single trial. The disks’ location and duration varied independently. One of these disks, the “attended disk”, was preceded by an attentional cue indicating the disk's location, attracting transient attention in advanced to the disk location. This attentional cue was either a typical onset cue (Experiments 1, 2, and 4) or a singleton cue (Experiment 3) that minimized the differences between the cues. The other disk, the “neutral disk”, was cued with a neutral cue that did not convey information regarding the disk location. We found that the attraction of transient attention to the location of the attended disk prolonged its perceived duration, but only when compared to brief nonattend stimuli.     

Effects of pitch distance and likelihood on the perceived duration of deviant auditory events

When a deviant (oddball) stimulus is presented within a series of otherwise identical (standard) stimuli, the duration of the oddball tends to be overestimated. Two experiments investigated factors affecting systematic distortions in the perceived duration of oddball stimuli. Both experiments used an auditory oddball paradigm where oddball tones varied in both their pitch distance from the pitch of a standard tone and their likelihood of occurrence. Experiment 1 revealed that (1) far-pitch oddballs were perceived to be longer than near-pitch oddballs, (2) effects of pitch distance were greater in low-likelihood conditions, and (3) oddballs in later serial positions were perceived to be longer than oddballs in earlier serial positions. The above effects held regardless of whether oddballs were higher or lower in pitch than the standard. Experiment 2 revealed a pattern of response times in an oddball detection task that generally paralleled the pattern of data observed in Experiment 1; across conditions, there was a negative correlation between detection times and perceived duration. Taken together, the results suggest that the observed effects of oddball pitch, likelihood, and position on perceived duration are at least partly driven by how quickly individuals are able to initiate timing the oddball following its onset. Implications for different theoretical accounts of the oddball effect are discussed.     

Test of Petter's rule for perceived surface stratification

Petter's rule applies to two-dimensional patterns formed by two overlapping surfaces that alternatively appear in front of one another. It states that the surface with the shorter contours in the region where the surfaces look superimposed has a greater probability of appearing in front of the other surface. An experiment is reported the results of which show that Petter's rule is valid for chromatically homogeneous and for uniformly dense dotted patterns, and invalid for different kinds of chromatically inhomogeneous patterns. Petter's rule has been found to be valid when the overlapping surfaces have contours with gaps. It is proposed that Petter's rule derives from the dynamics of filling-in of contour gaps.     

Gravity does rule for falling events

Hood (1995) reported a vertical invisible displacement task where the goal was to find a ball that was dropped down one of three chimneys connected to three hiding boxes below by opaque tubes. Preschool children exhibited perseverative search at the box directly below the chimney where the ball was dropped even though the tubes were always visible and the children were given numerous trials and feedback. This behavior was interpreted as a naive theory of gravity. The current study set out to test the naive gravity theory hypothesis by reversing the motion of the event on a television. On half of the trials the object appeared to fall up the tube into one of the boxes which were now on the top of the apparatus. There were significantly more errors for ‘down’ trials as compared to ‘up’ trials which supports the hypothesis that children are biased to infer that falling objects travel in a straight line whereas anti-gravity events do not conform to this naive theory.     

The perceived duration of gratings.

Since visible persistence of grating patterns increases with spatial frequency, it is often inferred that the perceived duration of a grating is also longer at higher spatial frequencies. However, other work has demonstrated that the perceived onset of a grating is also delayed at higher spatial frequencies. Thus it is impossible to infer the subjective duration from the results of visible persistence studies alone. In order to estimate perceived duration in the present study, reaction times (RTs) to grating onsets and offsets were measured for a range of spatial frequencies. The results indicate that although the perceived duration (ie the difference between offset and onset RTs) was consistently longer than the physical duration, the estimates of perceived duration did not vary with changes in spatial frequency. Differences between the present results and earlier findings are interpreted in the context of the different methods used to measure perceived offset.     

Temporal course of perceived auditory duration

A series of experiments explored the temporal course of the perceived duration of an auditory stimulus. A backward recognition masking paradigm was utilized, in which the subject was to determine which of two target durations was presented on a given trial. The target tone was followed, after a variable silent intertone interval, by a masking tone which could assume one of three possible durations. Identification of the long target was found to improve consistently with increases in the intertone interval. In contrast, identification of the short target was as accurate at the short as at the long intertone intervals. Blocking the intertone interval across experimental sessions eliminated these differences between the two target tones. Performance on both the long and the short target tones improved monotonically with increases in the intertone interval. When masking tone duration was randomized within an experimental session, identification of the long (short) target was most accurate with the longer (shorter) masking tone. Blocking the duration of the masking tone across experimental sessions eliminated the effect of the duration of the mask, but did not alter any of the other results. A model, proposed to account for the results, assumes that the percept of target duration grows over time, and can be terminated by the onset of the masking tone. The masking tone also acts to lengthen the perceived duration of the target tone, and this lengthening is a direct function of the duration of the masking tone.     

Exogenous visual attention prolongs perceived duration

Previous studies have shown that spatial attention prolongs the perceived duration of visual stimuli. Chen and O'Neill (Perception & Psychophysics, 63, 1229-1238, 2001) reported, however, the reversed result and thus challenged the generality of this attention effect. We therefore reinvestigated the influence of spatial attention on the perceived duration of visual stimuli in various experimental settings. In five experiments, perceived duration was longer for validly cued stimuli; thus, spatial attention was found to prolong perceived duration. In a further experiment, the specific conditions were such that neither the attention effect nor the reversed pattern, as found by Chen and O'Neill, emerged. Although we cannot provide a conclusive account of why Chen and O'Neill observed the reversed attention effect, the present results reinforce the generality of the spatial attention effect on perceived duration but also make advisable a systematic examination of the factors that might modulate this effect.     

Customer's perceived value of waiting time for service events

The authors address the effects of money gain and loss on individually perceived value as predicted by prospect theory in a time gain‐and‐loss context. Three experiments were conducted. Experiment 1 results support the prospect theory concept of value function. According to Experiment 2 results, the amount of money involved exerted different impacts on individual perceptions—specifically, study participants preferred gaining $1 on one occasion to gaining 50 cents over two occasions and preferred losing $1 one time to losing 50 cents twice. Further, the combined results indicate that the study participants held different perceptions of the value of “short time” versus “little money”—that is, they preferred saving an extra 2 minutes on one occasion to saving 1 minute on two occasions and preferred waiting an extra 1 minute two times to waiting an extra 2 minutes one time. Copyright © 2014 John Wiley & Sons, Ltd.     

Interaction of simultaneous visual events

Five experiments are reported in which a perceptual interaction between simultaneous brief events was investigated. Subjects judged whether a briefly presented stimulus was flickering or not. Performance was much more error prone when a similar unattended stimulus was presented at a relatively remote position in the visual field, thus confirming previous findings. Interference was obtained for stimuli presented both peripherally and centrally in the visual field. The effect was not confined to large stimuli, but the larger the interfering stimulus the greater the effect it had. Events in the auditory modality interfered with judgements made in the visual modality. Possible mechanisms for the interaction are discussed.     

Retrospective duration estimation of public events

In three experiments, we investigated subjects' retrospective estimation of the duration of publicly reported events such as, for example, the Falkland's war. In Experiment 1, duration estimates were found to be positively correlated with event knowledge, in keeping with Ornstein's (1969) model of duration estimation. Event duration was, however, generally underestimated, suggesting that the relationship between event knowledge and estimated duration might reflect an increase in estimation accuracy. Other results of Experiment 1 were consistent with this interpretation and suggested that the duration estimates might be largely reconstructed. In Experiment 2, duration estimates of specific events and general categories of events were found to be highly correlated, and the subjects in Experiment 3 indicated that they used knowledge of the general characteristic of different types of events to estimate event duration. Overall, reallife duration estimates appear to be based on a combination of specific event information and knowledge derived about that category of event.     

The duration and perceived intensity of sucrose taste

Thirty-two subjects judged the perceived intensity of each of four concentrations of sucrose over 2 min. Stimuli were either sipped and expectorated or flowed over the subject’s extended tongue. Ratio judgments on a line scale and category ratings were made. Sixteen of the subjects had had extensive training in judging the sensory attributes of food products, and another group of 16 subjects were untrained. The perceived intensity of sucrose rose to a peak within 5 or 10 sec, and then declined over 2 min. In both the sip and the flow conditions, the taste disappeared completely for 26 of 32 subjects. Stronger concentrations were perceived as having greater peak intensities and longer lasting taste. The differences between concentrations were enhanced when sipped rather than flowed over the tongue. Judgments of intensity and duration were largely unaffected by the training level of subjects and the use of different rating scales.     

Contrast influences perceived duration of brief time intervals

34 participants judged the duration of a 4-sec. interval which was preceded by a contextual interval of 2, 6, 10, or 14 sec. Underestimations of the test interval when the contextual intervals were longer suggested temporal durations are affected by a mechanism of comparing and contrasting analogous to the one producing some visual illusions.     

Discrete events as units of perceived time

In visual images, we perceive both space (as a continuous visual medium) and objects (that inhabit space). Similarly, in dynamic visual experience, we perceive both continuous time and discrete events. What is the relationship between these units of experience? The most intuitive answer may be similar to the spatial case: time is perceived as an underlying medium, which is later segmented into discrete event representations. Here we explore the opposite possibility--that our subjective experience of time itself can be influenced by how durations are temporally segmented, beyond more general effects of change and complexity. We show that the way in which a continuous dynamic display is segmented into discrete units (via a path shuffling manipulation) greatly influences duration judgments, independent of psychophysical factors previously implicated in time perception, such as overall stimulus energy, attention and predictability. It seems that we may use the passage of discrete events--and the boundaries between them--in our subjective experience as part of the raw material for inferring the strength of the underlying "current" of time.     

The effect of increased parasympathetic activity on perceived duration

Theories of human temporal perception suggest that changes in physiological arousal distort the perceived duration of events. Behavioural manipulations of sympathetic nervous system (SNS) activity support this suggestion, however the effects of behavioural manipulations of parasympathetic (PSNS) activity on time perception are unclear. The current study examined the effect of a paced respiration exercise known to increase PSNS activity on sub-second duration estimates. Participants estimated the duration of negatively and neutrally valenced images following a period of normal and paced breathing. PSNS and SNS activity were indexed by high-frequency heart-rate variability and pre-ejection period respectively. Paced breathing increased PSNS activity and reduced the perceived duration of the negative and neutrally valenced stimuli relative to normal breathing. The results show that manipulations of PSNS activity can distort time in the absence of a change in SNS activity. They also suggest that activities which increase PSNS activity may be effective in reducing the perceived duration of short events.