Pace alteration and estimation of time intervals

This experiment examined the effects on participants' estimates of interval duration of altering the pace of auditory stimuli contained within "filled" intervals. Because most previous studies on the filled interval effect have utilized visual displays, auditory stimuli were used to assess whether the effect would be present. In addition, previous studies compared two intervals, one of which was filled and the other unfilled. In the present study, both intervals were filled with tones at one of three rates (or "paces"): slow, medium, or fast. 25 participants (20 women) ages 18 to 29 years (M = 20.4, SD = 2.3) were recruited from psychology courses and programs. Participants first heard a "training" interval filled with tones at one of the three paces and then attempted to reproduce the duration of that training interval in the "test" interval. The pace of stimuli in each pair of training and test intervals was varied so participants received all possible combinations of paces of auditory stimuli during the training and test trial sets. Analysis showed that, when training pace was fast and test pace was medium or slow, participants' estimates were longer than the actual test interval durations. Conversely, when training pace was slow and test pace was medium or fast, participants' estimates were shorter than actual test interval durations. In addition, when judging shorter intervals, participants estimated more time had passed than actually had, while they estimated that less time had passed than actually had for longer intervals, thus providing support for Vierordt's law.     

Judgment of short time intervals while performing mathematical tasks

Ornstein (1969) suggested that the apparent duration of a time interval depended upon the memory storage size. This experiment tests this theory by studying duration estimates made while performing different types of information processing. Twenty Ss, introductory psychology students, served in each of the 30 conditions of the experiment. The six time intervals estimated by the method of reproduction were of lengths of 10, 12, 14, 16, 18, and 20 sec, and the five intervening tasks were doing nothing, reading numbers, adding, multiplying, and adding and multiplying in a random order. The results show that fewer items were output in the three arithmetic conditions, as compared with the reading condition, and also show that the duration estimates were shorter for these three conditions. Estimates of duration are related to amount of output, and also appear to be related to the type of processing done to produce this output.     

Judging the relative duration of multimodal short empty time intervals

Three experiments address the cause of the different performance levels found in time discrimination of empty intervals with durations near 250 msec. Performance differed according to the kind of sensory modality that marked the intervals. With a procedure in which the type of marker was randomized from trial to trial, it was shown that variability of discrimination judgments could not be attributed entirely to the variability of the criterion on which a judgment was based. Such a randomization slightly affects discrimination but provokes a reorganization related to marker conditions of the probabilities of judging an interval to be short or long. Moreover, it was shown that within intramodal conditions, physical characteristics of markers influence the discrimination performances. To account for the results generated with different marker-type intervals at 250 msec, we propose that two types of processor may be involved in duration discrimination: one is specifically related to a given sensory modality, whereas the other is aspecific and responsible for discrimination of intermodal intervals.     

Variations in perception of short time intervals during menstrual cycle

The hypothesis that women experience heightened sensitivity and responsivity premenstrually was tested by asking 10 women to produce short time intervals at four phases of the menstrual cycle. 10 men were assigned to "pseudo-cycles" and tested as a control. The test was based on the assumption that a greater sensitivity to stimuli is reflected in a "slowing down" of subjective time. The women produced the shortest time intervals three to four days before menses, confirming the hypothesis.     

No evidence for qualitative differences in the processing of short and long temporal intervals

Several lines of research suggest that two distinct timing mechanisms are involved in temporal information processing: a sensory mechanism for processing of durations in the range of milliseconds and a cognitively controlled mechanism for processing of longer durations. The present study employed a dual-task approach and a sensory interference paradigm to further elucidate the distinct timing hypothesis. Experiment 1 used mental arithmetic as a nontemporal secondary task, Experiment 2 a memory search task, and Experiment 3 a visuospatial memory task. In Experiment 4, a loudness manipulation was applied. Mental arithmetic and loudness manipulation affected temporal discrimination of both brief and long intervals, whereas the two remaining tasks did not influence timing performance. Observed differences in interference patterns may be explained by some tasks being more difficult than others. The overall pattern of results argues against two qualitatively distinct timing mechanisms, but is consistent with attention-based cognitive models of human timing.     

Response conflict determines sequential effects in serial response time tasks with short response-stimulus intervals

In serial choice reaction time (RT) tasks, performance in each trial critically depends on the sequence of preceding events. In this study, the authors specifically examined the mechanism underlying RT sequence effects at short response-stimulus intervals (RSIs), in which performance is impaired in the current trial N if events alternate rather than repeat from trial N-2 to trial N-1. Different accounts of this RT pattern in terms of perceptual noise, response-selection monitoring, and response conflict were tested in 4 experiments. Second-order RT costs were caused by the response sequence rather than the stimulus sequence. Manipulation of stimulus contrast, stimulus classification difficulty, and set-level compatibility did not modulate the response-related second-order RT effect, whereas this effect increased when spatially incompatible responses were demanded. These findings support a response conflict account of higher order sequential effects in short-RSI situations.     

Sequential effects in two-choice reaction time: Subjective expectancy and automatic after- effect at short response-stimulus intervals

Between three serial two-choice reaction-time tasks, the response-stimulus interval (RSI), stimulus-response compatibility, and practice were varied in order to examine two determinants of sequential effects — subjective expectancy and automatic aftereffect. It appears that subjective expectancy is absent when the RSI is below a critical minimum. In an incompatible task, however, this minimum is greater. This is interpreted in support of the single-channel hypothesis: the subject only builds up expectancies when the “central processor” is unoccupied. The automatic aftereffect increases as the RSI decreases. The decay of the aftereffect seems to take place mainly during the RSI and only to a minor degree during the reaction process. Normally, a strong aftereffect operates in a general way, but after extensive practice it becomes stimulus specific. A model is presented, which assumes that only at the initial stages of practice is the unused “neural pathway” inhibited each time the stimulus is an alternation.     

Perceptual interference decays over short unfilled intervals

The perceptual interference effect refers to the fact that object identification is directly related to the amount of information available at initial exposure. The present article investigated whether perceptual interference would dissipate when a short, unfilled interval was introduced between exposures to a degraded object. Across three experiments using both musical and pictorial stimuli, identification performance increased directly with the length of the unfilled interval. Consequently, significant perceptual interference was obtained only when the interval between exposures was relatively short (< 500 msec for melodies; < 300 msec for pictures). These results are consistent with explanations that attribute perceptual interference to increased perceptual noise created by exposures to highly degraded objects. The data also suggest that perceptual interference is mediated by systems that are not consciously controlled by the subject and that perceptual interference in the visual domain decays more rapidly than perceptual interference in the auditory domain.     

Short-term memory for time intervals

The effect of intertrial interval, preset interval, and retention interval on the performance of rats in a time estimation task was described. On each trial a signal was presented for a duration of 2 to 8 sec. Eighteen rats were trained to press one lever (the short response) if the signal was shorter than 4 sec, and another lever (the long response) if the signal was longer than 4 sec. When trials were massed (Experiment 1), the percentage long response was affected by the classification of the previous signal, but not by its actual duration. This suggests that the animals remembered the response made on the previous trial, but not the signal duration. If a response was not permitted on the previous trial (Experiment 2), the duration or classification of the previous signal had no effect on performance. This supports the conclusion from the first experiment and suggests that an animal can reset its internal clock in less than 2 sec. In Experiment 3, the difference limen of the psychophysical function increased with the duration of the retention interval, but the point of subjective equality did not change. This suggests that resetting of the internal clock occurs on a non-time dimension.     

Expecting a break in time estimation: attentional time-sharing without concurrent processing

The interference from nontemporal processing on concurrent time estimation is usually attributed to disruption in timing caused by attentional requirements of nontemporal processing. Here, we examined interruption in timing without concurrent nontemporal processing. Empty breaks of various durations, during time-interval production, lengthened produced intervals. Moreover, an effect of break location was observed: Intervals lengthened proportionally to prebreak duration. When cued and uncued uninterrupted trials were introduced, the lengthening was proportional to the duration for which a break was expected. It was concluded that attentional time-sharing between time estimation and expectation of its interruption contributed to the interference effect in time-estimation research, independently of any concurrent processing requirements during time estimation.     

Discrimination of visually perceived intervals of time

The discrimination of short intervals of time, demarcated by a foveally presented spatially distinct double pulse of light, was studied under several conditions of pulse intensity, angular diameter, and duration. We defined temporal acuity as a measure of discrimination capacity in terms of d′ values. It is shown that the acuity mechanism uses largely integrated information—in the spatial and temporal domain, up to at least 56′ and 32 msec, respectively. Acuity increases slightly with increasing integrated pulse energy, but seems quite independent of the presence of an adapting field of appreciable brightness. Studies on the effect of the foveal site aimed at by the pulses of light have shown that temporal projections lead to significantly poorer acuity values than nasal projections. Monoptic and dichoptic stimulation, however, are fully equivalent.