Perception of Biological Motion

Perception ◽  
1997 ◽  
Vol 26 (12) ◽  
pp. 1539-1548 ◽  
Author(s):  
Vicki Ahlström ◽  
Randolph Blake ◽  
Ulf Ahlström
Keyword(s):  
Spatial Frequency ◽  
Boundary Conditions ◽  
Structure From Motion ◽  
Biological Motion ◽  
Frequency Filtering ◽  
Unique Form ◽  
Contrast Polarity ◽  
Spatial Frequency Filtering ◽  
Point Light ◽  
Perception Of Biological Motion

Boundary conditions for perception of biological motion were explored with the use of computer-generated point-light animation sequences. Perception of this unique form of structure from motion is immune to variations in dot contrast polarity, dot disparity, and spatial-frequency filtering. Biological motion is perceived in texture-defined animation sequences that presumably stimulate only second-order motion pathways, and it is undisturbed by dichoptic presentation of portions of the animation tokens separately to the two eyes.

scholarly journals Neural and Neuromimetic Perception: A Comparative Study of Gender Classification from Human Gait

2020 ◽  
Vol 3 (1) ◽  
pp. 10402-1-10402-11
Author(s):  
Viswadeep Sarangi ◽  
Adar Pelah ◽  
William Edward Hahn ◽  
Elan Barenholtz
Keyword(s):  
Biological Motion ◽  
Human Perception ◽  
Movement Analysis ◽  
Inversion Effect ◽  
Human Gait ◽  
Computational Performance ◽  
Potential Applications ◽  
Perceptual Characteristics ◽  
Point Light ◽  
Perception Of Biological Motion

Abstract Humans are adept at perceiving biological motion for purposes such as the discrimination of gender. Observers classify the gender of a walker at significantly above chance levels from a point-light distribution of joint trajectories. However, performance drops to chance level or below for vertically inverted stimuli, a phenomenon known as the inversion effect. This lack of robustness may reflect either a generic learning mechanism that has been exposed to insufficient instances of inverted stimuli or the activation of specialized mechanisms that are pre-tuned to upright stimuli. To address this issue, the authors compare the psychophysical performance of humans with the computational performance of neuromimetic machine-learning models in the classification of gender from gait by using the same biological motion stimulus set. Experimental results demonstrate significant similarities, which include those in the predominance of kinematic motion cues over structural cues in classification accuracy. Second, learning is expressed in the presence of the inversion effect in the models as in humans, suggesting that humans may use generic learning systems in the perception of biological motion in this task. Finally, modifications are applied to the model based on human perception, which mitigates the inversion effect and improves performance accuracy. The study proposes a paradigm for the investigation of human gender perception from gait and makes use of perceptual characteristics to develop a robust artificial gait classifier for potential applications such as clinical movement analysis.

Biological Motion Shown Backwards: The Apparent-Facing Effect

Perception ◽  
10.1068/p3262 ◽  
2002 ◽  
Vol 31 (4) ◽  
pp. 435-443 ◽  
Author(s):  
Marina Pavlova ◽  
Ingeborg Krägeloh-Mann ◽  
Niels Birbaumer ◽  
Alexander Sokolov
Keyword(s):  
Visual Perception ◽  
Biological Motion ◽  
Presentation Mode ◽  
Reverse Transformation ◽  
Perceptual Identification ◽  
Perceptual Development ◽  
Apparent Direction ◽  
Point Light ◽  
Perception Of Biological Motion ◽  
Order Of Presentation

We examined how showing a film backwards (reverse transformation) affects the visual perception of biological motion. Adults and 6-year-old children saw first a point-light quadruped moving normally as if on a treadmill, and then saw the same display in reverse transformation. For other groups the order of presentation was the opposite. Irrespective of the presentation mode (normal or reverse) and of the facing of the point-light figure (rightward or leftward), a pronounced apparent-facing effect was observed: the perceptual identification of a display was mainly determined by the apparent direction of locomotion. The findings suggest that in interpreting impoverished point-light biological-motion stimuli the visual system may neglect distortions caused by showing a film backwards. This property appears to be robust across perceptual development. Possible explanations of the apparent-facing effect are discussed.

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