Date and time: Friday, 26 November 2021, 17:00-20:00 (JST), 8:00-11:00 (GMT)

Venue: The symposium will be held online through Zoom (ID/Passcode will be provided to registered participants).

Language: English

Organizer: Tatsuya Yoshizawa (Leader of a research team supported by Kanagawa University Grant for Joint Research)

Co-organizer：Research group ‘Universality and Diversity of Perceptual and Cognitive Systems’ at The Institute for Humanities Research, Kanagawa University

Speaker

• Ute Leonards (University of Bristol)
• Nick E. Scott-Samuel (University of Bristol)
• Goro Maehara (Kanagawa University)
• Tatsuya Yoshizawa (Kanagawa University)

Program

Abstracts

1.When vision leads the body astray

Ute Leonards (University of Bristol)

Twenty years ago, vision scientists Goodale and Humphrey stressed that “vision evolved in animals, not to enable them to ‘see’ the world, but to guide their movements through it” (Goodale & Humphrey, 1998, p.183). Yet, apart from research into obstacle avoidance and optic flow, even today there is little crosstalk between visual cognition and locomotion research, preventing us from understanding the role of visual information processing for real world behaviour. Here, I present work from my lab that reveals how the visual environment affects our gait, often in unexpected ways, even when we walk in obstacle-free environments on even ground. Experiments show how the validity of space perception is affected by floor patterns, impacting basic gait kinematics, foot placement, our ability to walk straight, and even overall walking confidence.

2. Effects of context on appearance: insights from camouflage

Nick E. Scott-Samuel (University of Bristol)

I will report some recent findings from my lab about various aspects of camouflage: translucency, dynamic background matching, distance dependent effects, and image complexity. I will argue that these offer useful generalisable lessons for perception.

3. An implausible impression of stereogram could be due to perceptual enhancement of luminance modulation.

Goro Maehara (Kanagawa University)

Although stereograms provide a sensation of depth, they often look artificial and somewhat unplausible. This could be partially due to their appearance of luminance contrast. Previous studies have shown that binocular summation in contrast detection thresholds went down to the level of probability summation as binocular disparity increased. However, little is known about the effect of binocular disparity on the appearance of luminance contrast patterns above threshold. To address this issue, we measured the luminance contrast of stereoscopic stimuli at the perceptual match to a certain fixed contrast owned by reference stimuli with zero binocular disparity. The matched contrast of the in-phase stimulus, which had luminance modulations in the same phase between eyes, was veridical at 0 degrees of binocular disparity and decreased as the disparity deviated from 0 degrees. On the other hand, there was no significant difference between the monocular matching contrast at 0 degrees and 0.5 degrees eccentricity, indicating that the reduction in matched contrast requires a stereoscopic presentation. These results suggest that suprathreshold stimuli with binocular disparity appears having higher luminance contrast than stimuli with zero disparity.

4. Luminance and chromatic information to produce visual plausibility in the material perception.

Tatsuya Yoshizawa (Kanagawa University)

What visual cue produces the visual plausibility of an object is an essential psychological question. Last decade, it was argued that statistical luminance information had a prominent role in perceiving texture in recognising an object's surface. We have explored how luminance and chromatic information contribute to the object perception, regarding local and global spatial structures and statistical property. We found that local luminance structure was crucially important information to perceive material surface. We also showed that chromatic information provided rich information to identify a particular object among objects within the identical category. This indicates that luminance and chromatic information has different function to produce visual plausibility in the material perception.