Spatial Effects on Temporal Categorisation

Perception ◽  
10.1068/p6165 ◽  
2009 ◽  
Vol 38 (5) ◽  
pp. 748-762 ◽  
Author(s):  
Marie-Ève Roussel ◽  
Simon Grondin ◽  
Peter Killeen
Keyword(s):  
Temporal Processing ◽  
Critical Role ◽  
Vertical Plane ◽  
Spatial Effects ◽  
Time Intervals ◽  
Spatial Factors ◽  
Upper Visual Field ◽  
Sensitivity Level ◽  
Marking Time ◽  
Perceived Duration

We examined the influence of spatial factors in temporal processing. Participants categorised as short or long empty intervals marked by two brief flashes delivered from locations differing in height and depth (experiment 1), or from two of three locations on a vertical plane (experiment 2). The perceived duration of intervals, as determined by the point of subjective equality, was affected by the height and depth of the signals (experiment 1). Experiment 2 showed that the point of fixation plays a critical role in perceived duration. The duration of an interval located in the upper visual field is perceived as longer when participants fixate the higher visual source and shorter when the fixation point is set in the middle; this latter result also generally applies when the fixation point is in the lower source. Finally, for the sensitivity level, there was a significant segment (upper versus lower) × direction (descending versus ascending) interaction in experiment 1; a similar interaction effect varied according to the fixation point in experiment 2. In experiment 2, the Weber fractions were around 0.22. Most results can be explained in terms of the need to shift attention from one visual source—for marking time intervals—to another.

Contrast Influences Perceived Duration of Brief Time Intervals

2004 ◽  
Vol 98 (2) ◽  
pp. 682-684
Author(s):  
Ted Jaeger ◽  
Jennifer Lang
Keyword(s):  
Time Intervals ◽  
Perceived Duration

scholarly journals Multiple Irrelevant Duration Information Affects the Perception of Relevant Duration Information: Interference With Selective Processing of Duration

i-Perception ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 204166952097322
Author(s):  
Hitomi Kawahara ◽  
Yuko Yotsumoto
Keyword(s):  
Temporal Processing ◽  
Target Stimulus ◽  
Target Duration ◽  
Visual Environment ◽  
Behavioral Experiments ◽  
Cortical Areas ◽  
Duration Information ◽  
The Mean ◽  
Selective Processing ◽  
Perceived Duration

In the human visual environment, the ability to perceive only relevant duration is important for various activities. However, a relatively small number of studies have investigated how humans process multiple durations, in comparison with the processing of one or two durations. We investigated the effects of multiple irrelevant durations on the perception of relevant duration. In four behavioral experiments, the participants were instructed to pay attention to a target stimulus while ignoring the distractors; then, they reproduced the target duration. We manipulated three aspects of the distractors: number, duration range, and cortical distance to the target. The results showed that the presence of multiple irrelevant durations interfered with the processing of relevant duration in terms of the mean perceived duration and the variability of the perceived duration. The interference was directional; that is, longer (shorter) irrelevant durations made the reproduced durations longer (shorter). Moreover, the interference was not likely to depend on the cortical distance between the target and the distractors, suggesting an involvement of relatively higher cortical areas. These results demonstrate that multiple irrelevant duration information affects the temporal processing of relevant duration information and suggest that multiple independent clocks assigned to each of the durations may not exist.

scholarly journals Perceived time slows during fleeting fun or fear

2018 ◽  
Vol 71 (2) ◽  
pp. 562-567 ◽  
Author(s):  
Mike Corke ◽  
Jason Bell ◽  
Stephanie C. Goodhew ◽  
Michael Smithson ◽  
Mark Edwards
Keyword(s):  
Temporal Processing ◽  
Weber’S Law ◽  
Emotional Stimuli ◽  
Weber's Law ◽  
Multiple Data ◽  
Data Points ◽  
Psychophysical Studies ◽  
Perceived Duration

Previous psychophysical studies at durations greater than 1000 ms have confirmed the anecdotal reports of an increase in the perceived duration of both positively and negatively valenced emotive stimuli; however, the results of studies at durations less than 1000 ms have been inconsistent. This study further investigated the effect of valence on the perception of durations less than 1000 ms. We used both positively and negatively valenced stimuli in order to compare their effects on the distortion of duration, and we tested multiple data points within the sub-one-second range. We found an increase in the perceived duration of both positively and negatively valenced emotional stimuli at all data points. This is consistent with studies at durations longer than 1000 ms and also with models of temporal processing. We also confirmed that Weber fractions, within the range tested, followed the generalized form of Weber’s law.

Spatial effects on extreme precipitation in the coastal areas of southeast China

2020 ◽  
Author(s):  
Weikang Qian ◽  
Xun Sun
Keyword(s):  
Extreme Precipitation ◽  
Extreme Value Distribution ◽  
Coastal Areas ◽  
Generalized Extreme Value Distribution ◽  
Precipitation Event ◽  
Human Society ◽  
Spatial Effects ◽  
Southeast China ◽  
Spatial Factors ◽  
Daily Precipitation Data

<p>Extreme precipitation event, along with its secondary disasters, is one of the largest natural hazards leading to massive loss in human society. In the coastal areas of southeast china, tropical cyclones (TC) frequently visit the region with intensive precipitation in summer and autumn. Besides TC induced extreme precipitation, convectional precipitation is an alternative reason of extreme precipitation. This study investigated the spatial effects of the extreme precipitation during the raining season for both TC induced and non-TC induced extreme precipitation. The seasonal maximum daily precipitation data through 94 stations in southeast coastal areas of China from 1964 to 2013 were used. We developed a hierarchical Bayesian model with generalized extreme value distribution (GEV) to quantitatively assess the effects of spatial factors on the extreme precipitation. TC induced and non-TC induced extreme precipitation are modelled separately. It was found that the spatial factors that affect the TC induced and non-TC induced extreme precipitation are clearly different. For the TC induced extreme precipitation, the distance to the coastline has been found to be a significant spatial covariate that affects both the location and scale parameter of GEV across the whole areas, while spatial factors are diverse in different locations for non-TC induced extreme precipitation.</p>

scholarly journals Contrasting task demands alter the perceived duration of brief time intervals

1994 ◽  
Vol 56 (6) ◽  
pp. 649-657 ◽  
Author(s):  
Thomas F. Sawyer ◽  
Peter J. Meyers ◽  
Stacy J. Huser
Keyword(s):  
Task Demands ◽  
Time Intervals ◽  
Perceived Duration

scholarly journals The Kappa Effect With Only Two Visual Markers

2016 ◽  
Vol 29 (8) ◽  
pp. 703-725 ◽  
Author(s):  
Tsuyoshi Kuroda ◽  
Simon Grondin ◽  
Makoto Miyazaki ◽  
Katsuya Ogata ◽  
Shozo Tobimatsu
Keyword(s):  
Visual Angle ◽  
Relative Frequency ◽  
Interstimulus Interval ◽  
Velocity Model ◽  
Spatial Distance ◽  
Spatial Effects ◽  
Time Intervals ◽  
Visual Markers ◽  
Kappa Effect ◽  
Empty Time

The kappa effect is a spatiotemporal illusion where duration is overestimated with the increase of space. This effect is typically demonstrated with three successive stimuli marking two neighboring empty time intervals, and the classical imputed velocity model, in principle, does not help to predict any spatial effects when only two stimuli, marking single intervals, are presented on each trial. We thus conducted three experiments, examining requirements for the occurrence of the kappa effect with only two visual stimuli. An interstimulus interval between the two stimuli was 217 (short) or 283 ms (long), and participants categorized the presented interval as ‘short’ or ‘long’. The key finding is that participants tended to respond ‘short’ more frequently than ‘long’ when both stimuli were delivered from the same location, whereas the relative frequency of ‘long’ responses was increased when the two stimuli were delivered from different locations in most directions (i.e., horizontally, vertically, diagonally; Experiment 1). This kappa effect clearly occurred when each stimulus was located 8° apart from the fovea in visual angle, but it was reduced when each stimulus was further deviated from the fovea, regardless of whether the two stimuli were presented in the vertical or the horizontal direction (Experiments 2 and 3). Moreover, increasing the spatial distance between the two stimuli from 15 to 30 cm magnified the effect only in a limited condition (Experiment 3). Implications of these results were discussed in terms of the Bayesian model predicting the effects of spatial acuity.

scholarly journals Hippocampal-striatal functional connectivity supports processing of temporal expectations from associative memory

2019 ◽  
Author(s):  
Vincent van de Ven ◽  
Chanju Lee ◽  
Julia Lifanov ◽  
Sarach Kochs ◽  
Henk Jansma ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Temporal Processing ◽  
Temporal Structure ◽  
Dorsal Striatum ◽  
Motor Preparation ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Time Intervals ◽  
Hippocampal Subfields ◽  
Associative Processing

AbstractThe hippocampus and dorsal striatum are both associated with temporal processing, but they are thought to play distinct roles. The hippocampus has been reported to contribute to storing temporal structure of events in memory, whereas the striatum contributes to temporal motor preparation and reward anticipation. Here, we asked whether the striatum cooperates with the hippocampus in processing the temporal context of memorized visual associations. In our task, participants were trained to implicitly form temporal expectations for one of two possible time intervals associated to specific cue-target associations, and subsequently were scanned using 7T functional magnetic resonance imaging. During scanning, learned temporal expectations could be violated when the pairs were presented at either the learned or not-learned time intervals. When temporal expectations were not met during testing trials, activity in hippocampal subfields CA3/CA2 and CA1 decreased while right putamen activity increased, compared to when temporal expectations were met. Further, psycho-physiological interactions showed that functional connectivity between left CA1 and caudate, as well as between putamen and caudate, decreased when temporal expectations were not met. Our results indicate that the hippocampus and striatum cooperate to process implicit temporal expectation from mnemonic associations, with different but complementary contributions from caudate and putamen. Our findings provide further support for a hippocampal-striatal network in temporal associative processing.

Categorical Rhythm Perception as a Result of Unilateral Assimilation in Time-Shrinking

1998 ◽  
Vol 16 (2) ◽  
pp. 201-222 ◽  
Author(s):  
Takayuki Sasaki ◽  
Yoshitaka Nakajima ◽  
Gert Ten Hoopen
Keyword(s):  
Total Duration ◽  
Considerable Change ◽  
Time Interval ◽  
Rhythm Perception ◽  
Time Intervals ◽  
Empty Time Interval ◽  
Method Of Adjustment ◽  
Empty Time ◽  
Perceptual Mechanism ◽  
Perceived Duration

In previous studies, we established an illusion of time perception that we called time-shrinking: an empty time interval, immediately preceded by a slightly shorter time interval, is underestimated. In the first experiment of the present study, we examined the perceived duration not only of the second interval (t2), but also of the first interval (tl). The empty time intervals tl and t2, making a total duration of 90,180, 360, or 720 ms, were presented such that the time ratio between them changed systematically. The points of subjective equality of tl and t2 were established by the method of adjustment. In the patterns typically susceptible to timeshrinking, that is, in which t2 was underestimated, tl was perceived almost vertically. In the second experiment, listeners had to bisect an empty duration of 180 ms, marked by sound bursts. The bisecting sound marker was positioned closer to the initial marker than to the final one. Thus, tl had to be shorter than t2 in order for a regular pattern to be perceived. In the third experiment, just-noticeable forward and backward displacements of the middle sound marker were measured by a transformed updown method. The prediction that the interval of uncertainty was closer to the initial than to the final sound marker was confirmed. The three experiments demonstrated the existence of unilateral temporal assimilation, and it is argued that this perceptual mechanism causes a category of 1:1 rhythms, despite a considerable change in temporal ratio between two contiguous time intervals.

scholarly journals Effectiveness of Desensitizing Agents in relieving the Pre- and Postcementation Sensitivity for Full Coverage Restorations: A Clinical Evaluation

2013 ◽  
Vol 14 (5) ◽  
pp. 858-865 ◽  
Author(s):  
Naveen Gupta ◽  
Upendra Natha Reddy ◽  
P Leela Vasundhar ◽  
K Sita Ramarao ◽  
KVV Pratap Varma ◽  
...  
Keyword(s):  
Clinical Evaluation ◽  
Glass Ionomer Cement ◽  
Glass Ionomer ◽  
Time Intervals ◽  
Full Coverage ◽  
Sensitivity Level ◽  
Abutment Teeth ◽  
Desensitizing Agents ◽  
Tooth Mousse ◽  
Ionomer Cement

ABSTRACT Patients frequently report sensitivity of prepared abutment teeth during the temporization period and after the final cementation of full coverage restoration. Purpose of this clinical investigation was to evaluate the effectiveness of desensitizing agents in reducing the pre- and postcementation sensitivity for full coverage restorations and to compare the relative efficacy of three in office applied desensitizing agents in relieving the postcementation sensitivity with the use of glass ionomer luting cement. Materials and methods This study consisted of 30 patients requiring either full coverage restoration or 3 unit fixed partial denture. Total of 40 restorations (n = 40) were made and were randomly assigned into four groups comprising 10 restoration (n = 10) in each group. Group C control where no desensitizer application was done, group BB applied with BisBlock dentin desensitizer (Bisco Inc.), group ST applied with Systemp desensitizer (Ivoclar Vivadent), group GC applied with GC Tooth Mousse desensitizer (GC Asia). Desensitizer application was done immediately after the tooth preparation. Sensitivity of the tested abutment was determined by the patient response to cold, hot and bite stimuli and were recorded on visual analog scale (VAS). Sensitivity level scores was evaluated at 4 time intervals, i.e. 1 week after desensitizer application at baseline precementation appointment and others at 5 minutes, 1 day and 1 week postcementation appointment. VAS score data was statistically analyzed using one-way ANOVA followed by post hoc Tukey's test. Results BisBlock and GC Tooth Mousse desensitizer resulted in statistically significant (p < 0.01) reduction in postcementation sensitivity of glass ionomer cement in comparison to Systemp desensitizer at 5 minutes, 1 week postcementation time interval with no statistical difference was seen between all desensitizer groups at 1 day postcementation. Application of BisBlock and GC Tooth Mousse desensitizer resulted in highly significant (p < 0.01) reduction in sensitivity level at the end of 1 week. Clinical significance Desensitizer's application on the prepared abutment teeth is considerably effective in relieving both pre- and postcementation sensitivity for full coverage restoration over the short duration of time. Immediate reduction in postoperative sensitivity relatively in a short time period may be beneficial in terms of patient's comfort. Nonetheless, multicenter long-term clinical trials should be conducted to confirm the results. Conclusion Efficacy of BisBlock and GC Tooth Mousse desensitizer was more in relieving the postcementation sensitivity of glass ionomer cement at various time intervals in comparison to Systemp desensitizer. In conclusion, application of desensitizers was beneficial to reduce the pre- and postcementation abutment sensitivity. How to cite this article Gupta N, Reddy UN, Vasundhar PL, Ramarao KS, Varma KVVP, Vinod V. Effectiveness of Desensitizing Agents in relieving the Pre- and Postcementation Sensitivity for Full Coverage Restorations: A Clinical Evaluation. J Contemp Dent Pract 2013;14(5):858-865.

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