title: Perception of elasticity in the kinetic illusory object with phase differences in inducer motion.
abstract: BACKGROUND
  It is known that subjective contours are perceived even when a figure involves motion. However, whether this includes the perception of rigidity or deformation of an illusory surface remains unknown. In particular, since most visual stimuli used in previous studies were generated in order to induce illusory rigid objects, the potential perception of material properties such as rigidity or elasticity in these illusory surfaces has not been examined. Here, we elucidate whether the magnitude of phase difference in oscillation influences the visual impressions of an object's elasticity (Experiment 1) and identify whether such elasticity perceptions are accompanied by the shape of the subjective contours, which can be assumed to be strongly correlated with the perception of rigidity (Experiment 2).
  
  
  RESULTS
  In Experiment 1, the phase differences in the oscillating motion of inducers were controlled to investigate whether they influenced the visual impression of an illusory object's elasticity. The results demonstrated that the impression of the elasticity of an illusory surface with subjective contours was systematically flipped with the degree of phase difference. In Experiment 2, we examined whether the subjective contours of a perceived object appeared linear or curved using multi-dimensional scaling analysis. The results indicated that the contours of a moving illusory object were perceived as more curved than linear in all phase-difference conditions.
  
  
  CONCLUSIONS
  These findings suggest that the phase difference in an object's motion is a significant factor in the material perception of motion-related elasticity.
authors.affiliation: Food Function Division, National Food Research Institute, National Agriculture and Food Research Organization, Ibaraki, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Masuda
authors.forename: Kazuki
authors.initials: K
authors.lastname: Sato
authors.forename: Takuma
authors.initials: T
authors.lastname: Murakoshi
authors.forename: Ken
authors.initials: K
authors.lastname: Utsumi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kimura
authors.forename: Nobu
authors.initials: N
authors.lastname: Shirai
authors.forename: So
authors.initials: S
authors.lastname: Kanazawa
authors.forename: Masami K
authors.initials: MK
authors.lastname: Yamaguchi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Wada
mesh_terms: D000328:Adult; D004548:Elasticity; D005260:Female; D006801:Humans; D007088:Illusions / Q000502:physiology*; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D009038:Motion; D014796:Visual Perception / Q000502:physiology; D055815:Young Adult