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

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 Humans quickly learn to blink strategically in response to environmental task demands

2018 ◽  
Vol 115 (9) ◽  
pp. 2246-2251 ◽  
Author(s):  
David Hoppe ◽  
Stefan Helfmann ◽  
Constantin A. Rothkopf
Keyword(s):  
Task Performance ◽  
Psychological Factors ◽  
Task Demands ◽  
Active Perception ◽  
Time Intervals ◽  
Detection Experiment ◽  
Cognitive States ◽  
Complex Interactions ◽  
Key Characteristics ◽  
Future Events

Eye blinking is one of the most frequent human actions. The control of blinking is thought to reflect complex interactions between maintaining clear and healthy vision and influences tied to central dopaminergic functions including cognitive states, psychological factors, and medical conditions. The most imminent consequence of blinking is a temporary loss of vision. Minimizing this loss of information is a prominent explanation for changes in blink rates and temporarily suppressed blinks, but quantifying this loss is difficult, as environmental regularities are usually complex and unknown. Here we used a controlled detection experiment with parametrically generated event statistics to investigate human blinking control. Subjects were able to learn environmental regularities and adapted their blinking behavior strategically to better detect future events. Crucially, our design enabled us to develop a computational model that allows quantifying the consequence of blinking in terms of task performance. The model formalizes ideas from active perception by describing blinking in terms of optimal control in trading off intrinsic costs for blink suppression with task-related costs for missing an event under perceptual uncertainty. Remarkably, this model not only is sufficient to reproduce key characteristics of the observed blinking behavior such as blink suppression and blink compensation but also predicts without further assumptions the well-known and diverse distributions of time intervals between blinks, for which an explanation has long been elusive.

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.

Multimodal Integration of Interval Duration: Temporal Ventriloquism or Changes in Pacemaker Rate?

2013 ◽  
Vol 1 (2) ◽  
pp. 189-215 ◽  
Author(s):  
Maria Dolores de la Rosa ◽  
Karin M. Bausenhart
Keyword(s):  
Paired Comparison ◽  
Multimodal Integration ◽  
Interval Duration ◽  
Bias Effect ◽  
Comparison Task ◽  
Time Intervals ◽  
Reproduction Task ◽  
Temporal Ventriloquism ◽  
Reproduction Method ◽  
Perceived Duration

Previous studies demonstrated that perceived duration of visual intervals is strongly influenced by conflicting auditory intervals. However, it remains unclear which mechanisms underlie this multimodal integration of interval duration. To investigate this issue, we employed a reproduction task with empty (Experiment 1) or filled (Experiment 2) intervals, and a paired-comparison task (Experiment 3) to assess perceived duration of visually marked intervals, which could be accompanied by auditory marked intervals with congruent (same) or conflicting (longer and shorter) durations. First, we predicted that conflicting auditory intervals would bias the perceived duration of visual intervals towards the duration of the auditory ones. Second, according to pacemaker-accumulator models, two different mechanisms might contribute to multimodal interval integration: changes in pacemaker rate or changes of the switch component based on temporal ventriloquism effects. In the former case, the multimodal bias effect should increase with increasing interval duration. In the latter case, the effect should remain constant across interval durations. All experiments showed a strong influence of auditory interval duration on perceived visual duration. In Experiments 1 and 2, this bias effect unexpectedly decreased with increasing interval duration, which might be due to limitations of the employed duration reproduction method. In Experiment 3, however, the observed multimodal bias effect remained clearly constant across all interval durations. This finding supports the idea that multimodal integration of conflicting time intervals is mainly determined by a temporal ventriloquism effect, which affects the switch component of a pacemaker-accumulator mechanism. In addition, we demonstrated that bimodal congruent intervals are perceived as longer than unimodal visual ones. For filled (Experiment 2), but not for empty (Experiment 1) intervals, this effect seems to be caused by an increase in pacemaker rate.

Rotational Characteristics of the Green Solar Corona: 1947-1991

1994 ◽  
Vol 144 ◽  
pp. 139-141 ◽  
Author(s):  
J. Rybák ◽  
V. Rušin ◽  
M. Rybanský
Keyword(s):  
Solar Corona ◽  
World Wide ◽  
Rotation Period ◽  
Original Data ◽  
Coronal Emission ◽  
Time Intervals ◽  
Data Set ◽  
The World ◽  
Coronal Emission Line ◽  
Homogeneous Data

AbstractFe XIV 530.3 nm coronal emission line observations have been used for the estimation of the green solar corona rotation. A homogeneous data set, created from measurements of the world-wide coronagraphic network, has been examined with a help of correlation analysis to reveal the averaged synodic rotation period as a function of latitude and time over the epoch from 1947 to 1991.The values of the synodic rotation period obtained for this epoch for the whole range of latitudes and a latitude band ±30° are 27.52±0.12 days and 26.95±0.21 days, resp. A differential rotation of green solar corona, with local period maxima around ±60° and minimum of the rotation period at the equator, was confirmed. No clear cyclic variation of the rotation has been found for examinated epoch but some monotonic trends for some time intervals are presented.A detailed investigation of the original data and their correlation functions has shown that an existence of sufficiently reliable tracers is not evident for the whole set of examinated data. This should be taken into account in future more precise estimations of the green corona rotation period.

Prolonged Fixation Studies For Spaceflight

1973 ◽  
Vol 31 ◽  
pp. 332-333
Author(s):  
Robert Corbett ◽  
Delbert E. Philpott ◽  
Sam Black
Keyword(s):  
High Pressure ◽  
Living Systems ◽  
Prolonged Storage ◽  
Time Intervals ◽  
Early Signs ◽  
Large Numbers

Observation of subtle or early signs of change in spaceflight induced alterations on living systems require precise methods of sampling. In-flight analysis would be preferable but constraints of time, equipment, personnel and cost dictate the necessity for prolonged storage before retrieval. Because of this, various tissues have been stored in fixatives and combinations of fixatives and observed at various time intervals. High pressure and the effect of buffer alone have also been tried.Of the various tissues embedded, muscle, cartilage and liver, liver has been the most extensively studied because it contains large numbers of organelles common to all tissues (Fig. 1).

Ultrastructure of Lymphatic Capillaries in the Transport of Colloidal Particles

1967 ◽  
Vol 25 ◽  
pp. 186-187
Author(s):  
L. V. Leak ◽  
J. F. Burke
Keyword(s):  
Connective Tissue ◽  
Colloidal Particles ◽  
Ultrastructural Level ◽  
Vital Role ◽  
Time Intervals ◽  
Thorium Dioxide ◽  
Lymphatic Capillary ◽  
Tissue Area ◽  
Rapid Removal ◽  
Tissue Fluids

The vital role played by the lymphatic capillaries in the transfer of tissue fluids and particulate materials from the connective tissue area can be demonstrated by the rapid removal of injected vital dyes into the tissue areas. In order to ascertain the mechanisms involved in the transfer of substances from the connective tissue area at the ultrastructural level, we have injected colloidal particles of varying sizes which range from 80 A up to 900-mμ. These colloidal particles (colloidal ferritin 80-100A, thorium dioxide 100-200 A, biological carbon 200-300 and latex spheres 900-mμ) are injected directly into the interstitial spaces of the connective tissue with glass micro-needles mounted in a modified Chambers micromanipulator. The progress of the particles from the interstitial space into the lymphatic capillary lumen is followed by observing tissues from animals (skin of the guinea pig ear) that were injected at various time intervals ranging from 5 minutes up to 6 months.

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