scholarly journals Assimilation and contrast in the perception of an auditorily presented empty time interval preceded by another empty time interval

Author(s):  
Yoshitaka Nakajima ◽  
Emi Hasuo ◽  
Yuki Haraguchi
1993 ◽  
Vol 11 (1) ◽  
pp. 15-38 ◽  
Author(s):  
Gert Ten Hoopen ◽  
Gaston Hilkhuysen ◽  
Gert Vis ◽  
Yoshitaka Nakajima ◽  
Fumihiko Yamauchi ◽  
...  

When one very short empty time interval follows right after another, the second one can be underestimated considerably, but only if it is longer than the first one. We coined the term "time-shrinking" for this illusory phenomenon in our previous studies. Although we could relate our finding to some studies of rhythm perception, we were not able to explain the illusion. The present article presents our attempt to understand the mechanism that causes the time-shrinking. Four experiments are reported. The first one ruled out the possibility that the illusion results from a difficulty in resolving the temporal structure. The second experiment showed that the listener was not inadvertently judging the duration of the first interval instead of that of the second one. In addition, this experiment yielded more information about the time window within which the illusion occurs. The third experiment showed that forward masking of the sound markers, delimiting the empty durations, could not explain the illusion either. Furthermore, this experiment revealed a clue to the mechanism of time-shrinking: competition between expected and observed temporal positions. The fourth experiment further examined the temporal conditions that give rise to the illusion and showed that categorical perception plays a crucial role in the formation of the illusion. In the general discussion, we argue that the illusion is due to an asymmetric process of temporal assimilation.


1998 ◽  
Vol 16 (2) ◽  
pp. 201-222 ◽  
Author(s):  
Takayuki Sasaki ◽  
Yoshitaka Nakajima ◽  
Gert Ten Hoopen

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.


Perception ◽  
1987 ◽  
Vol 16 (4) ◽  
pp. 485-520 ◽  
Author(s):  
Yoshitaka Nakajima

An attempt to construct a general theory of duration perception is presented. First, four experiments are reported in which the supplement hypothesis, on the relation between two or three empty durations, was examined: the subjective duration of a subjectively empty time interval is directly proportional to its physical duration plus a constant of ~ 80 ms. This hypothesis could be applied to the ratio judgments of auditorily marked empty durations between 40 and 600 ms given serially. It could also explain the discrepancies between musically notated rhythms and the corresponding physical performed rhythms in very simple rhythm patterns consisting of three tones. Next, three earlier experiments on discriminations of empty durations marked by sound bursts were also reanalyzed. Within the range 40–600 ms, the absolute just noticeable difference of an empty duration was almost directly proportional to the standard duration plus a constant of about 80 ms. If the supplement hypothesis is accepted, this means that the relative just noticeable difference of the subjective duration was constant. Finally, the processing time hypothesis is presented: subjective duration is directly proportional to the physical time required to process the given empty duration. This processing is considered to begin with the detection of the first marker, and to end ~ 80 ms after the detection of the second marker.


Perception ◽  
1988 ◽  
Vol 17 (1) ◽  
pp. 93-118 ◽  
Author(s):  
Yoshitaka Nakajima ◽  
Seishi Nishimura ◽  
Ryunen Teranishi

A study is reported on the perception of empty time intervals marked by auditory signals. Nakajima's supplement hypothesis, which states that the subjective duration of a subjectively empty time interval is proportional to its physical duration plus a constant of ~80 ms, was examined quantitatively. Although this hypothesis has been used to explain various general aspects of time perception, from a global viewpoint, it has lacked the quantitative data necessary to describe the shape of the psychophysical functions mathematically. In the present study, subjects used two positive numbers to estimate the subjective ratio ( m: n) between the durations of two serial or separate empty intervals. The psychophysical functions for empty durations 50–600 ms long could be approximated by a straight line with a positive y-intercept, as predicted by the hypothesis. The effective range of the hypothesis could be extended to ~1200 ms. A power function (without any modifications) also gave good approximations. The reliability and validity of the supplement hypothesis are discussed.


1991 ◽  
Vol 8 (4) ◽  
pp. 431-448 ◽  
Author(s):  
Yoshitaka Nakajima ◽  
Gert Ten Hoopen ◽  
René Van Der Wilk

When two very short time intervals are presented serially by sound markers (in such a way that they share a common marker) the subject's duration judgments of the second time interval can be affected by the duration of the first interval. Such a conspicuous effect has not been reported in the literature. Standard empty time intervals of 120, 240, 480, and 720 msec were preceded by a neighboring empty time interval of various physical durations, and subjects adjusted a comparison empty time interval to the same subjective duration as these standards. We found clear underestimations of the standard duration when its physical duration was 120 msec. For example, when the preceding duration was 45 msec, the relative underestimation was about 40%. Because such a stable and remarkable underestimation appeared in a very simple situation, this phenomenon may be called a new illusion. Such an illusion did not appear when the time interval to be judged was succeeded by another time interval. At present we cannot explain the illusion, but in the general discussion we attempt to relate it to some findings in rhythm perception.


2001 ◽  
Vol 15 (4) ◽  
pp. 256-274 ◽  
Author(s):  
Caterina Pesce ◽  
Rainer Bösel

Abstract In the present study we explored the focusing of visuospatial attention in subjects practicing and not practicing activities with high attentional demands. Similar to the studies of Castiello and Umiltà (e. g., 1990) , our experimental procedure was a variation of Posner's (1980) basic paradigm for exploring covert orienting of visuospatial attention. In a simple RT-task, a peripheral cue of varying size was presented unilaterally or bilaterally from a central fixation point and followed by a target at different stimulus-onset-asynchronies (SOAs). The target could occur validly inside the cue or invalidly outside the cue with varying spatial relation to its boundary. Event-related brain potentials (ERPs) and reaction times (RTs) were recorded to target stimuli under the different task conditions. RT and ERP findings showed converging aspects as well as dissociations. Electrophysiological results revealed an amplitude modulation of the ERPs in the early and late Nd time interval at both anterior and posterior scalp sites, which seems to be related to the effects of peripheral informative cues as well as to the attentional expertise. Results were: (1) shorter latency effects confirm the positive-going amplitude enhancement elicited by unilateral peripheral cues and strengthen the criticism against the neutrality of spatially nonpredictive peripheral cueing of all possible target locations which is often presumed in behavioral studies. (2) Longer latency effects show that subjects with attentional expertise modulate the distribution of the attentional resources in the visual space differently than nonexperienced subjects. Skilled practice may lead to minimizing attentional costs by automatizing the use of a span of attention that is adapted to the most frequent task demands and endogenously increases the allocation of resources to cope with less usual attending conditions.


2001 ◽  
Vol 17 (1) ◽  
pp. 25-35 ◽  
Author(s):  
G. Leonard Burns ◽  
James A. Walsh ◽  
David R. Patterson ◽  
Carol S. Holte ◽  
Rita Sommers-Flanagan ◽  
...  

Summary: Rating scales are commonly used to measure the symptoms of attention deficit/hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), and conduct disorder (CD). While these scales have positive psychometric properties, the scales share a potential weakness - the use of vague or subjective rating procedures to measure symptom occurrence (e. g., never, occasionally, often, and very often). Rating procedures based on frequency counts for a specific time interval (e. g., never, once, twice, once per month, once per week, once per day, more than once per day) are less subjective and provide a conceptually better assessment procedure for these symptoms. Such a frequency count procedure was used to obtain parent ratings on the ADHD, ODD, and CD symptoms in a normative (nonclinical) sample of 3,500 children and adolescents. Although the current study does not provide a direct comparison of the two types of rating procedures, the results suggest that the frequency count procedure provides a potentially more useful way to measure these symptoms. The implications of the results are noted for the construction of rating scales to measure the ADHD, ODD, and CD symptoms.


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