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Displaying 1-14 of 14 articles from this issue
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Article type: Cover
Pages Cover1-
Published: July 15, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (14K) -
Article type: Index
Pages Toc1-
Published: July 15, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (54K) -
Yuichi WADA, Takayoshi KATOArticle type: Article
Session ID: HIR99-41
Published: July 15, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThis study examined the existence of a visual field anisotropy for orienting of sustained attention in a dual-task setting. In the experiment, a circular arrangement of stimulus elements(Gabor patches)was successively presented during a 40-min vigil. A primary task was a simple detection task requiring subjects to determine whether all of the elements were same or whether there was an odd element in the upper left, upper right, lower left, or lower right visual fields. A secondary task was a frequency discrimination of tone singnals. Results indicated that, for the primary detection task, the perceptual sensitivity(A')in the left visual field was higher than in the right visual field but decreased over time on task while A' in the right visual field remained stable over time. The implications for the functional lateral asymmetry in human sustained attention are discussed.View full abstractDownload PDF (741K) -
Takayuki TakiuraArticle type: Article
Session ID: HIR99-42
Published: July 15, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSTemmporal summation in the visual system was investigated for the supraliminal flashes by the flash discrimination and by the visual masking technique. For the flashes of variable durations with constant energy, the perfect temporal summation of the flash energy was observed, whose critical duration changed with the flash energy level. The critical duration for the double flash was shorter than that for the single flash. These findings provide the basic data for the psychophysical model of the supraliminal temporal summation.View full abstractDownload PDF (703K) -
Koji SAKAI, Toshio INUIArticle type: Article
Session ID: HIR99-43
Published: July 15, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSWe propose a feature-segmentation model for the representation of a single pattern in short-term visual memory(STVM). The structure of the model is that three processes interact to determine a memory sensitivity(d'): aquisition, memory, and decision. The basic assumptions of the model can be expressed such that(1)Forgetting occures because the representation of each convex part is individually distorted with memory noise, (2)The amount of memory noise with each convex part is fixed ragardless of pattern complexity, (3)The probability that memory noise occurs is nearly zero if the presented figure is within memory capacity, (4)Memory noise increases as a linear function of the retention interval. Simulation showed that the data of Sakai & Inui(1999a, 1999b, 1999c)were quite compatible with the present model. It is suggested that segmented convex parts are stored in STVM with a parallel rehearsal.View full abstractDownload PDF (842K) -
Takeshi Sugio, Toshio Inui, Kayako Matsuo, Masako Matsuzawa, Toshiharu ...Article type: Article
Session ID: HIR99-44
Published: July 15, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSUsing fMRI, the internal mechanism involved in object recognition from non-canonical viewpoints was examined. We used a passive observation task and found several brain areas activated more strongly in the non-canonical viewing condition compared to the canonical viewing condition. It was found that the fusiform gyrus and posterior part of inferior temporal cortex(BA19/37)are involved in the processing of shape information. On the other hand, posterior parietal cortex(BA7), mainly the superior parietal lobule, and premotor cortex(BA6/9, 44)are involved in visuospatial processing and accessing sensorimotor knowledge. These results might indicate that recognition from non-canonical viewpoints is accomplished using functional properties of the object, such as which part of the object is suited as a handle.View full abstractDownload PDF (946K) -
Toshikazu MatsuiArticle type: Article
Session ID: HIR99-45
Published: July 15, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSEnergy-based motion detection models have been used as a model of the Fourier motion detection mechanism in human vision. However, conditions to guarantee the models' validity are not necessarily clarified. In this paper, we evaluate the energy models' performance in reproducing reverse motion perception(motion illusion)and Fourier mechanism's disruption for two-frame and multi-frame apparent motion, respectively, and find appropriate conditions. It is shown that two kinds of energy models' temporal filters should be Hilbert transforms of each other and that the filters' band-width should be as broad as the visual filter's. Computationally, these results suggest that there also exists a temporal Hilbert filter in the Fourier mechanism and that the broad band-width of the visual temporal filters is reasonable. Moreover, the optimized energy model gives an interpretation to the disruption mechanism.View full abstractDownload PDF (865K) -
Wataru Teramoto, Shinichi KitaArticle type: Article
Session ID: HIR99-46
Published: July 15, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThis study examined with a visual search paradigm how eccentricities influenced the detection of expansion/contraction. Observers searched for a expansion target among contraction distractors and vise versa. The times to find targets presented near fixation were compared with those at more peripheral. In the latter condition, there was significant search asymmetry between expansion and contraction, although in the former condition there was no search asymmetry. Furthermore, this search asymmetry observed only in the latter condition was different from those normally known in a visual search paradigm. This difference between conditions may reflect dual mechanisms in both attentional and the visual system.View full abstractDownload PDF (798K) -
Kenzo SAKURAI, Hiroshi ONOArticle type: Article
Session ID: HIR99-47
Published: July 15, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSWe found a depth/motion trade-off in viewing motion parallax display consisting of expansion/contraction dot motion yoked to forward/backward head movements. We simulated surfaces with vertical or horizontal sine wave corrugations and measured the extent of perceived depth and that of perceived motion. The extent of perceived depth in the binocular condition was smaller than that in the monocular condition, but the extent of perceived motion was larger. We conclude that the retinal displacement that the visual system cannot convert into depth is seen as motion.View full abstractDownload PDF (607K) -
Takefumi HAYASHI, Satoshi FUKAYA, Toshio INUIArticle type: Article
Session ID: HIR99-48
Published: July 15, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSMoving random dot patterns are used to investigate the surface reconstruction mechanisms by motion parallax. An optokinetic nystagmus is observed in accordance with the average dot velocity. It was proved that pure velocity gradients without average velocity component are projected on the retina. Then, the same random dot pattern is displayed on a head-mounted display, and the influence of the observer's self motion is investigated. The perceived surface is inverted not by self motion but by eye movement. Further, a model of surface reconstruction is discussed in terms of a regularization theory.View full abstractDownload PDF (834K) -
Toshihiro SHIMIZU, Sumio YANOArticle type: Article
Session ID: HIR99-49
Published: July 15, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSInduced effects to the body sway by oscillating frontal-plane rotation of a visual wide-field stimulus and synchronously moving auditory stimuli were discussed. By extending the visual field of the visual stimulus with presentation of the synchronously moving auditory stimuli, the body sway was more strongly induced. The results suggested that individually induced effects to the body sway by audiovisual stimuli were not simply summed, but interactive effects between audiovisual stimuli existed. Magnitude of the induced effects by the interaction between audiovisual stimuli depended on the visual field of the visual stimulus, and was increased by extending the visual field.View full abstractDownload PDF (703K) -
Takashi KUSANO, Satoshi FUTAKUCHI, Shuji MORIArticle type: Article
Session ID: HIR99-50
Published: July 15, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSUsing a one-interval forced-choice task, Wark & Mori(1996)and Futakuchi(1998)found that intensity discrimination of pure tones was improved by presentation of attentional cues. However, in their experiment, the previous stimulus tone as well as the cue tone might be used as the standard for the subject's intensity judgement. To exclude such possibilities in the present study we used a two-interval forced-choice task and examined effects of attentional cues. The results of two experiments showed that the discrimination performance was lowered by randomizing the stimulus frequency, as observed in the previous studies, although the cues did not improve the performance.View full abstractDownload PDF (649K) -
Shuji Mori, Satoshi FutakuchiArticle type: Article
Session ID: HIR99-51
Published: July 15, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSIn this paper, we report a series of studies on auditory attention in intensity discrimination of pure tones(Futakuchi & Mori, 1999; Mori & Ward, 1991, 1992; Ward & Mori, 1996). In a one-interval-forced-choice task, we measured attentional effects on intensity discrimination, by presenting frequency cues before the pure-tone signals. The results are summarized as follows; (1)Cue tones direct the listener's attention to the signal frequency, resulting in improvement of intensity resolution; (2)Visual cues are effective only for musicians; (3)Presenting signal and cue tones to contralateral ears does not change attentional effects; (4)Attentional effects occur between 200 and 2000 msec after the cue tones.View full abstractDownload PDF (709K) -
Article type: Appendix
Pages App1-
Published: July 15, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (88K)
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