Vibrotactile frequency recognition: forward and backward masking effects

Forward and backward vibrotactile recognition masking was investigated in 4 subjects with 240-Hz and 160-Hz targets of 20 ms duration and four 200-Hz masks, using interstimulus intervals (ISIs) ranging from -500 to 500 ms. Two of the masks (short) were 20 ms and two (long) were 200 ms in duration. One of each set of masks was matched in subjective intensity to the targets, but the others were more intense. The range of ISIs over which masking was obtained was comparable to that found by Massaro (1970) with auditory stimuli. Both short masks produced more masking than either long mask except at short ISIs. Larger mask intensities increased masking only at very short ISIs, and longer mask durations increased backward but not forward masking.     

Feature processing during high-rate auditory selective attention

Auditory event-related brain potentials (ERPs) and reaction times were, analyzed in a selective attention task in which subjects attended to tone pips presented at high rates-Xinterstimulua intervals [ISIs] of 40-200 msec). Subjects responded to infrequent target tones of a specified frequency (250 or 4000 Hz) and location (left or right ear) that were louder than otherwise identical tones presented randomly to the left and right ears. Negative difference (Nd) waves were isolated by subtracting ERPs to tones with no target features from ERPs to the same tones when they shared target location, frequency, or both frequency and location cues. Nd waves began 60-70 msec after tone onset and lasted until 252–350 msec after tone onset, even for tones with single attended cues. The duration of Nd waves exceeded the ISIs between successive tones, implying that several stimuli underwent concurrent analysis. Nd waves associated with frequency processing had scalp distributions different from those associated with location processing, implying that the features were analyzed in distinct cortical areas. Nd waves specific to auditory feature conjunction were isolated. These began at latencies of 110–120 msec, some 30-40 msec after the Nds to single features. The relative timing of the different Nd waves suggests that auditory feaure conjunction begins after a brief parallel analysis of individual features but before feature analysis is complete.     

Classical conditioning of the rabbit's nictitating membrane response under fixed and mixed CS-US intervals

The rabbit's nictitating membrane response was classically conditioned to a tone CS, followed by an electric shock US, at two randomly alternating CS-US interstimulus intervals (ISIs). Different groups were exposed to different proportions of 200- and 700-msec ISIs. The study revealed: (a) CR percentage was a direct function of the proportion of 200-msec ISIs; (b) trials to the first test-trial CR were an inverse function of the proportion of 200-msec ISIs; (c) CR onset latencies decreased over training; (d) CR peak latencies coincided with the temporal loci of the US; and (e) groups exposed to both ISIs acquired double-peaked CRs. Moreover, the amplitudes of nictitating membrane responses in the present experiment paralleled certain quantitative aspects of the free operant key peck response rates of pigeons trained under two mixed inter-reinforcement intervals. The results were discussed with respect to the micromolar response shaping and macromolecular CS-trace accounts of classical conditioning.     

Discrimination and generalization by rats of temporal stimuli lasting for minutes

In three experiments, rats learned to respond differentially to reinforced and nonreinforced trials when the length of the intertrial interval (ITI) predicted the trial outcome (reinforcement or nonreinforcement). Rats in control groups, for whom the length of the ITI did not predict the outcome, did not show differential performance on nonreinforced and reinforced trials. Generalization gradients obtained following discrimination training were comparable to those obtained following discrimination training with other types of discriminative stimuli. That is, groups which had shown differential performance in discrimination training yielded generalization gradients with fastest speeds at the previously reinforced ITIs, slowest speeds at the previously nonreinforced ITIs, and intermediate speeds at ITIs of intermediate length. Control groups yielded flat gradients across all ITIs tested. These effects were shown for relative time discrimination (short time = reinforcement, long time = nonreinforcement, or the reverse) and also for an absolute time discrimination (long and short time = reinforcement, middle time = nonreinforcement or the reverse). This method was effective for time duration measured in minutes rather than seconds, as is more commonly the case.     

Ultra-precise quantal timing: Evidence from simultaneity thresholds in long-range apparent movement

Conditions for the disappearance of long-range apparent movement were investigated. In an experiment on beta motion, critical interstimulus intervals (ISIs) of downward simultaneity thresholds for stimuli presented in continuous alternation were determined for exposure durations (EDs) varying from 3 to 160 msec. Each subject performed each test twice. Data were collected in three sessions, each for one of three angular separations (3°, 6°, and 12°) and the full set of EDs. The distribution of critical ISIs collapsed across subjects, EDs, and angular separations shows sharp maxima at regular distances within a range of 0–110 msec ISI. Significant or near-significant peaks were found at ISIs of 5, 9,22,27, 43, 55, and 107 msec. Although mean critical ISIs shifted with spatial separation, no essential shift of the main maxima occurred. Evidence of a periodic modulation with a period duration of 4.5 msec was obtained from the distributions of differences between critical ISIs of the first tests and their replications, which exhibit extremely low standard deviations (< 10 msec). These results agree well with previous analyses (Geissler, 1987, 1992) that led to a taxonomic model of quantal timing, briefly summarized in this paper. Further consequences are discussed and related to earlier developments (Geissler, 1991, 1992,1997).     

Ultra-precise quantal timing: evidence from simultaneity thresholds in long-range apparent movement.

Conditions for the disappearance of long-range apparent movement were investigated. In an experiment on beta motion, critical interstimulus intervals (ISIs) of downward simultaneity thresholds for stimuli presented in continuous alternation were determined for exposure durations (EDs) varying from 3 to 160 msec. Each subject performed each test twice. Data were collected in three sessions, each for one of three angular separations (3 degrees, 6 degrees, and 12 degrees) and the full set of EDs. The distribution of critical ISIs collapsed across subjects, EDs, and angular separations shows sharp maxima at regular distances within a range of 0-110 msec ISI. Significant or near-significant peaks were found at ISIs of 5, 9, 22, 27, 43, 55, and 107 msec. Although mean critical ISIs shifted with spatial separation, no essential shift of the main maxima occurred. Evidence of a periodic modulation with a period duration of 4.5 msec was obtained from the distributions of differences between critical ISIs of the first tests and their replications, which exhibit extremely low standard deviations (< 10 msec). These results agree well with previous analyses (Geissler, 1987, 1992) that led to a taxonomic model of quantal timing, briefly summarized in this paper. Further consequences are discussed and related to earlier developments (Geissler, 1991, 1992, 1997).     

Contextual effects in duration experience

The role of contextual factors on duration estimates was investigated, employing 6 time intervals ranging from 15 to 35 sec (demarcated by the onset and termination of a display panel of lights). When compared with earlier research, the results suggest that duration estimates are affected by the context of the stimulus intervals with regard to other stimuli in the series. Specifically, those stimuli that were overestimated when they were the shortest members of the series were underestimated when they were the longest intervals of the stimulus series. In addition, a lengthening effect was observed: duration estimates increased over blocks of trials for all stimulus intervals.     

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 mechanisms tanderlying differences in duration discrimination with filled and empty intervals are discussed.     

Duration perception in crossmodally-defined intervals

How humans perform duration judgments with multisensory stimuli is an ongoing debate. Here, we investigated how sub-second duration judgments are achieved by asking participants to compare the duration of a continuous sound to the duration of an empty interval in which onset and offset were marked by signals of different modalities using all combinations of visual, auditory and tactile stimuli. The pattern of perceived durations across five stimulus durations (ranging from 100 ms to 900 ms) follows the Vierordt Law. Furthermore, intervals with a sound as onset (audio-visual, audio-tactile) are perceived longer than intervals with a sound as offset. No modality ordering effect is found for visualtactile intervals. To infer whether a single modality-independent or multiple modality-dependent time-keeping mechanisms exist we tested whether perceived duration follows a summative or a multiplicative distortion pattern by fitting a model to all modality combinations and durations. The results confirm that perceived duration depends on sensory latency (summative distortion). Instead, we did not find evidence for multiplicative distortions. The results of the model and the behavioural data support the concept of a single time-keeping mechanism that allows for judgments of durations marked by multisensory stimuli.     

不同ISI下异同判断的同反应启动效应

通过改变刺激对中的第一个刺激消失到第二个刺激出现之间的间隔 (interstimulusinterval,简称ISI) ,并控制呈现的刺激前后试验不重复 ,分别进行不同形状白色图形的异同判断实验和不同颜色圆形的异同判断实验 ,系统地考察不同ISI下异同判断的同反应启动效应 ,研究异同判断的加工机制。两个实验均采用 2 (前次试验类型 :异、同 )× 2 (当前试验类型 :异、同 )× 6(ISI :1 0 0ms、2 0 0ms、30 0ms、40 0ms、50 0ms、60 0ms)重复测量设计。被试为2 1名大学本科生 ,其中男生 1 0名 ,女生 1 1名。结果发现 ,在两实验中的每一种ISI条件下 ,同反应后的试验的反应时均显著短于异反应后的试验的反应时 ,即表现出显著的同反应启动效应。实验的结果支持异同判断的双过程模型 ,并表明双加工机制可能是序列工作的     

The relationship between variability of intertap intervals and interval duration

Summary Subjects tracked intervals in a synchronization paradigm at interval durations of 180, 210, 240, 270, 300, 400, 500, 600, 700, 800, 900, and 1,000 ms. The variability of intertap intervals (ITIs) shows a sudden increase near 300 ms. This increase is interpreted as indicating the transition from automatic to controlled movement. It is suggested that the sudden change in the variability of ITIs does not reflect the operation of different timing mechanisms at short and long intervals, but differences in the way in which attentional processes come to bear on movement initiation for different interval durations. In contrast to previous findings reported in the literature, a U-shaped function between interval duration and variability in the 300-to-1,000-ms range was not observed.     

Effects of partial reinforcement on conditioning,conditional probabilities,asymptotic performance,and extinction of the rabbit’s nictitating membrane response

Classical conditioning and extinction of the rabbit nictitating membrane response was investigated under 100 per cent, and two 50 per cent reinforcement conditions (50% equated total trials, and 50% equated reinforced trials) at average intertriai intervals (ITIs) of 30 and 60 sec. It was found that: (1) partial reinforcement reduced the rate of conditioning, but all groups eventually attained asymptomatic performance levels near 100 per cent; (2) first-order and second-order conditional probabilities following reinforced and nonreinforced trials were virtually identical; and (3) no partial reinforcement extinction effect (PREE) was observed.     

The role of tone duration in dichotic temporal order judgment

Over the past two decades, a number of studies have been based on the dichotic temporal order judgment (TOJ) paradigm, to compare auditory temporal processing in various subpopulations to that of young, normal controls. The reported estimates of dichotic TOJ thresholds, expressed as the interstimulus intervals (ISIs) for 75 % accuracy among the controls, have varied. In the present study, we examined the influence of tone duration, within the 10- to 40-msec range, on dichotic TOJ accuracy and threshold. The results indicated that increases in either ISI or tone duration increased dichotic TOJ accuracy similarly, implying that changes in tone duration may affect dichotic TOJs simply by adding to the delay between onset of the tone at the lead ear and onset of the tone at the lag ear. The dichotic TOJ thresholds from three published studies that had used tones as stimuli and the dichotic thresholds from the present study all fell within 0.5 standard deviations from the theoretical line of a 10-msec reduction in threshold for every 10-msec increase in tone duration. When the dichotic TOJ threshold data from the present study and from the published studies were converted to stimulus onset asynchronies (SOAs) and plotted as a function of tone duration, they fell very close to or on a zero-slope line, indicating that when ISI and duration are summed to yield an SOA, dichotic TOJ thresholds are invariant to tone duration within the range of 10–40 msec.     

Tactile perception of sequentially presented spatial patterns

Tactile pattern recognition was studied by presenting pairs of alphabetic shapes in rapid succession at the same anatomical location, the subject being required on each trial to identify bath of the patterns. Experimental variables were the duration of each stimulus and the time between stimuli. Three aspects of the observed interaction were (1) an increase in letter reversals for very short interstimulus intervals; (2) a greater percentage of first-response errors for short-stimulus onset intervals and a greater percentage of second-response errors for long-stimulus onset intervals; and (3) a crossover in the first- and second-response error rates in the range of 100 to 200 msec. after the onset of the first stimulus. These results are consistent with some of the temporal properties of models proposed for analogous visual tasks.     

Attenuation of age-related conditioning deficits in humans by extension of the interstimulus interval

Young (17-22 years) and older (61-86 years) persons underwent classical conditioning of the eye-blink response to a tone conditioned stimulus (CS) and an airpuff unconditioned stimulus (UCS) at 1 of 3 interstimulus intervals (ISIs; 400, 650, and 900 ms). As in a previous study, older subjects conditioned more slowly and emitted fewer conditioned responses at the optimal 400-ms ISI. At longer ISIs, however, this age-related disruption of classical conditioning was attenuated. These differences in conditioning were not due to nonassociative factors, such as sensitivity to the tone CS or airpuff UCS or to differences in spontaneous blink rate, nor were they due to differences in general cognitive abilities. The results are discussed in terms of the role of temporal relationships between stimuli in conditioning across the life span.     

Temporal reproductions are influenced by an internal reference: Explaining the Vierordt effect

Several findings from duration perception literature suggest that when making decisions about time, participants rely on an internal reference memory for time rather than merely on the current physical stimuli. According to a recent account, such an internal reference is formed by a continuous dynamic updating process that integrates duration information from previous trials and the current trial. In the present work, we show how such a dynamic mechanism can account for the classical yet unresolved Vierordt effect, which refers to the overestimation of relatively short and the underestimation of relatively long temporal intervals. We conducted an experiment to examine this and related predictions by means of a temporal reproduction task. Specifically, participants were presented with two successive time intervals — a standard s with constant duration and a comparison c with variable duration. Instead of performing a comparison judgment, however, the participants were subsequently cued to reproduce one of the two presented stimuli. Reproductions were affected not only by the temporal position of the to-be-reproduced stimulus, but also by the stimuli presented on earlier trials. These results support the notion of a dynamically updated internal reference underlying our judgments about the time elapsed, which might also be the basis of the Vierordt effect.     

Timing in trace conditioning of the nictitating membrane response of the rabbit (Oryctolagus cuniculus): scalar, nonscalar, and adaptive features

Using interstimulus intervals (ISIs) of 125, 250, and 500 msec in trace conditioning of the rabbit nictitating membrane response, the offset times and durations of conditioned responses (CRs) were collected along with onset and peak latencies. All measures were proportional to the ISI, but only onset and peak latencies conformed to the criterion for scalar timing. Regarding the CR's possible protective overlap of the unconditioned stimulus (US), CR duration increased with ISI, while the peak's alignment with the US declined. Implications for models of timing and CR adaptiveness are discussed.     

Hear it playing low and slow: How pitch level differentially influences time perception

Variations in both pitch and time are important in conveying meaning through speech and music, however, research is scant on perceptual interactions between these two domains. Using an ordinal comparison procedure, we explored how different pitch levels of flanker tones influenced the perceived duration of empty interstimulus intervals (ISIs). Participants heard monotonic, isochronous tone sequences (ISIs of 300, 600, or 1200 ms) composed of either one or five standard ISIs flanked by 500 Hz tones, followed by a final interval (FI) flanked by tones of either the same (500 Hz), higher (625 Hz), or lower (400 Hz) pitch. The FI varied in duration around the standard ISI duration. Participants were asked to determine if the FI was longer or shorter in duration than the preceding intervals. We found that an increase in FI flanker tone pitch level led to the underestimation of FI durations while a decrease in FI flanker tone pitch led to the overestimation of FI durations. The magnitude of these pitch-level effects decreased as the duration of the standard interval was increased, suggesting that the effect was driven by differences in mode-switch latencies to start/stop timing. Temporal context (One vs. Five Standard ISIs) did not have a consistent effect on performance. We propose that the interaction between pitch and time may have important consequences in understanding the ways in which meaning and emotion are communicated.     

Motion perception over long interstimulus intervais

Recent studies using moving arrays of textured micropatterns have suggested that motion percep-tion can be supported by two mechanisms, one quasilinear and sensitive to the motion of luminance-defined local texture, the other nonlinear and coding motion of contrast-defined envelopes of texture (Baker & Hess, 1998; Boulton & Baker, 1993b). Here we used similar patterns to study motion percep-tion under conditions previously shown to isolate the nonlinear mechanism (low micropattern densi-ties and positive interstimulus intervals [ISIs]). We measured direction discrimination for two-flash ap-parent motion over a much larger range of ISIs, and susceptibility to masking by incoherently moving “distractor” micropatterns. The results suggest that two nonlinear mechanisms can support motion perception under these conditions. One operates only for relatively short ISIs (less than c. 100 msec), is sensitive to small spatial displacements, and is relatively insensitive to distractor masking. The other operates over much longer ISIs, is insensitive to small spatial displacements, and is highly disrupted by distractor masking. These results are in line with previous studies suggesting that three mechanisms support motion perception.     

Sensation seeking and stimulus intensity as modulators of cortical,cardiovascular, and electrodermal response: A cross-modality study

Previous studies have related the trait of sensation seeking to augmenting of the evoked potential (EP) in both visual and auditory modalities and to electrodermal and heart rate (HR) orienting and defensive reactions. The present study examined all of these phenomena in the same sample of subjects in order to replicate previous findings, and investigate cross-modality consistency and relationships between cortical and peripheral responses. Fifty-four male subjects, scoring high or low on the Disinhibition Sensation Seeking Scale, were exposed to 4 intensities of auditory stimuli (tones) on one occasion and visual stimuli (light flash) on another. Two interstimulus (ISIs) intervals were used for each set of stimuli: first a 17 sec series, and then a 2 sec series. High disinhibitors showed EP augmenting and lows reducing on 3 of the 4 series; differences were significant on two of them. High disinhibitors showed stronger orienting (deceleratory) HR responses to visual and auditory stimuli while lows showed stronger defensive (acceleratory) HR responses. HR responses were significantly correlated across stimulus modalities. Auditory and visual EP slope measures were correlated only for the long ISI series.