Off on the Wrong Foot: Local Features in Biological Motion

Perception ◽  
10.1068/p6140 ◽  
2009 ◽  
Vol 38 (4) ◽  
pp. 522-532 ◽  
Author(s):  
Daniel R Saunders ◽  
Julia Suchan ◽  
Nikolaus F Troje
Keyword(s):  
Motion Perception ◽  
Discrimination Task ◽  
Biological Motion ◽  
Large Body ◽  
Detection Task ◽  
Observer Performance ◽  
Local Motion ◽  
Motion Patterns ◽  
Direction Discrimination ◽  
Biological Motion Perception

Biological-motion perception consists of a number of different phenomena. They include global mechanisms that support the retrieval of the coherent shape of a walker, but also mechanisms which derive information from the local motion of its parts about facing direction and animacy, independent of the particular shape of the display. A large body of the literature on biological-motion perception is based on a synthetic stimulus generated by an algorithm published by James Cutting in 1978 ( Perception7 393–405). Here we show that this particular stimulus lacks a visual invariant inherent to the local motion of the feet of a natural walker, which in more realistic motion patterns indicates the facing direction of a walker independent of its shape. Comparing Cutting's walker to a walker derived from motion-captured data of real human walkers, we find no difference between the two displays in a detection task designed such that observers had to rely on global shape. In a direction discrimination task, however, in which only local motion was accessible to the observer, performance on Cutting's walker was at chance, while direction could still be retrieved from the stimuli derived from the real walker.

Body Configuration Modulates the Usage of Local Cues to Direction in Biological-Motion Perception

2011 ◽  
Vol 22 (12) ◽  
pp. 1543-1549 ◽  
Author(s):  
Masahiro Hirai ◽  
Dorita H. F. Chang ◽  
Daniel R. Saunders ◽  
Nikolaus F. Troje
Keyword(s):  
Motion Perception ◽  
Biological Motion ◽  
Visual Display ◽  
Local Motion ◽  
Direction Discrimination ◽  
Biological Motion Perception ◽  
Vertical Location ◽  
Local Inversion ◽  
Point Light ◽  
Local Cues

The presence of information in a visual display does not guarantee its use by the visual system. Studies of inversion effects in both face recognition and biological-motion perception have shown that the same information may be used by observers when it is presented in an upright display but not used when the display is inverted. In our study, we tested the inversion effect in scrambled biological-motion displays to investigate mechanisms that validate information contained in the local motion of a point-light walker. Using novel biological-motion stimuli that contained no configural cues to the direction in which a walker was facing, we found that manipulating the relative vertical location of the walker’s feet significantly affected observers’ performance on a direction-discrimination task. Our data demonstrate that, by themselves, local cues can almost unambiguously indicate the facing direction of the agent in biological-motion stimuli. Additionally, we document a noteworthy interaction between local and global information and offer a new explanation for the effect of local inversion in biological-motion perception.

Dichotomy in Biological Motion Perception: Pigeons Use Feet Local Motion to Determine Direction

2017 ◽  
Author(s):  
Michelle Tong ◽  
Priyanka Mensinkai
Keyword(s):  
Motion Perception ◽  
Biological Motion ◽  
The Body ◽  
The Other ◽  
Local Motion ◽  
Visual Processes ◽  
Biological Motion Perception ◽  
Ecological Implications ◽  
Direction Of Movement ◽  
Point Light

The study examines the visual processes underlying the detection of the motion of land animals, or biological motion. The ability to process the motion of other living beings has profound ecological implications in the wilderness and in our everyday life. Earlier models suggest that there are two distinct ways to process this information. One uses the shape of an entire figure and one uses the motion of one part of the body. In this experiment, we aim to study whether the local motion of the feet or the configuration of the body is used to determine the direction into which a figure is facing. We do this by training pigeons to discriminate facing direction of a stationary walking point‐light figure. Pigeons chose one of two walkers by pecking on a touch screen. Once the task was learned, catch trials of backwards walkers were introduced. This kind of display gives the pigeon opposing information about direction. While the shape of the walker tells them it is walking one way, the feet give the impression that it is moving in the other. Pigeons were successful in learning to discriminate directions and at the introduction of the catch trials, most birds used the local motion cue of the feet to determine direction. The results indicate that pigeons seem to being using the feet, rather than the shape of a figure, to process direction of movement. In conjunction with previous literature, this study suggests that there exists an innate “life detector” specialized for filtering the movement of the feet.

Reference Frames for Orientation Anisotropies in Face Recognition and Biological-Motion Perception

Perception ◽  
10.1068/p3392 ◽  
2003 ◽  
Vol 32 (2) ◽  
pp. 201-210 ◽  
Author(s):  
Nikolaus F Troje
Keyword(s):  
Face Recognition ◽  
Motion Perception ◽  
Biological Motion ◽  
Reference Frames ◽  
Recognition Performance ◽  
Recognition Task ◽  
Detection Task ◽  
Social Recognition ◽  
Biological Motion Perception ◽  
Strong Orientation

Both face recognition and biological-motion perception are strongly orientation-dependent. Recognition performance decreases if the stimuli are rotated with respect to their normal upright orientation. Here, the question whether this effect operates in egocentric coordinates or in environmental coordinates is examined. In addition to the use of rotated stimuli the observers were also rotated and tested both with a same–different face-recognition task and with a biological-motion detection task. A strong orientation effect was found that depended only on the stimulus orientation relative to the observer. This result clearly indicates that orientation effects in both stimulus domains operate in an egocentric frame of reference. This finding is discussed in terms of the particular requirement of extracting sophisticated information for social recognition and communication from faces and biological motion.

scholarly journals Category-specific interference of object recognition with biological motion perception

2010 ◽  
Vol 10 (13) ◽  
pp. 16-16 ◽  
Author(s):  
K. Wittinghofer ◽  
M. H. E. de Lussanet ◽  
M. Lappe
Keyword(s):  
Object Recognition ◽  
Motion Perception ◽  
Biological Motion ◽  
Biological Motion Perception

scholarly journals Developmental Origins of Biological Motion Perception

2012 ◽  
pp. 121-138
Author(s):  
Willem E. Frankenhuis ◽  
H. Clark Barrett, ◽  
Scott P. Johnson
Keyword(s):  
Motion Perception ◽  
Biological Motion ◽  
Developmental Origins ◽  
Biological Motion Perception
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