Pitting optic flow, object motion, and biological motion against each other

Koerfer, Krischan; Lappe, Markus

doi:10.1167/jov.20.8.18

Cited by 5 publications

(13 citation statements)

References 57 publications

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“…More importantly, a rightward advantage was observed in the present study, whereas no such asymmetry was found in the abovementioned studies (Fujimoto, 2003; Fujimoto et al, 2009; Fujimoto & Sato, 2006; Fujimoto & Yagi, 2007, 2008; Koerfer & Lappe, 2020; Mayer et al, 2019). Such rightward advantage has also been observed with another social cue (i.e., eye gaze).…”

Section: Discussioncontrasting

confidence: 75%

“…Our findings further indicated that high‐level visual information (i.e., biological signals) can also influence the perceived direction of apparent motion. Note that some recent studies have also explored how BM signals interact with scene dynamics (e.g., moving grating and optic flow; Fujimoto, 2003; Fujimoto et al, 2009; Fujimoto & Sato, 2006; Fujimoto & Yagi, 2007, 2008; Koerfer & Lappe, 2020; Mayer et al, 2019). For instance, it has been found that BM cues displayed peripherally were processed incidentally and could affect the performance of direction discrimination of the BM walker at the fovea (Thornton & Vuong, 2004).…”

Section: Discussionmentioning

confidence: 99%

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Life motion signals bias the perception of apparent motion direction

Ge,

Yu,

Huang

et al. 2023

British J of Psychology

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Walking direction conveyed by biological motion (BM) cues, which humans are highly sensitive to since birth, can elicit involuntary shifts of attention to enhance the detection of static targets. Here, we demonstrated that such intrinsic sensitivity to walking direction could also modulate the direction perception of simultaneously presented dynamic stimuli. We showed that the perceived direction of apparent motion was biased towards the walking direction even though observers had been informed in advance that the walking direction of BM did not predict the apparent motion direction. In particular, rightward BM cues had an advantage over leftward BM cues in altering the perception of motion direction. Intriguingly, this perceptual bias disappeared when BM cues were shown inverted, or when the critical biological characteristics were removed from the cues. Critically, both the perceptual direction bias and the rightward advantage persisted even when only local BM cues were presented without any global configuration. Furthermore, the rightward advantage was found to be specific to social cues (i.e., BM), as it vanished when non‐social cues (i.e., arrows) were utilized. Taken together, these findings support the existence of a specific processing mechanism for life motion signals and shed new light on their influences in a dynamic environment.

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Section: Discussioncontrasting

confidence: 75%

Section: Discussionmentioning

confidence: 99%

Life motion signals bias the perception of apparent motion direction

Ge,

Yu,

Huang

et al. 2023

British J of Psychology

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“…The Scrambled walkers served as a control for possible effects on flow parsing of the nonrigid motion produced by the walker. This was critical for our study because the presence of nonrigid motion of humans (and scrambled versions of human PLWs) affects optic flow perception (Riddell & Lappe, 2017 ; Koerfer & Lappe, 2020 ; Hülemeier & Lappe, 2020 ) and, therefore, might also affect flow parsing. For the Intact walker, we induced conflicts between biological features (i.e., facing and articulation) and the direction of scene-relative motion.…”

Section: Introductionmentioning

confidence: 99%

Flow parsing and biological motion

Mayer¹,

Riddell

Lappe

2021

Atten Percept Psychophys

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Flow parsing is a way to estimate the direction of scene-relative motion of independently moving objects during self-motion of the observer. So far, this has been tested for simple geometric shapes such as dots or bars. Whether further cues such as prior knowledge about typical directions of an object’s movement, e.g., typical human motion, are considered in the estimations is currently unclear. Here, we adjudicated between the theory that the direction of scene-relative motion of humans is estimated exclusively by flow parsing, just like for simple geometric objects, and the theory that prior knowledge about biological motion affects estimation of perceived direction of scene-relative motion of humans. We placed a human point-light walker in optic flow fields that simulated forward motion of the observer. We introduced conflicts between biological features of the walker (i.e., facing and articulation) and the direction of scene-relative motion. We investigated whether perceived direction of scene-relative motion was biased towards biological features and compared the results to perceived direction of scene-relative motion of scrambled walkers and dot clouds. We found that for humans the perceived direction of scene-relative motion was biased towards biological features. Additionally, we found larger flow parsing gain for humans compared to the other walker types. This indicates that flow parsing is not the only visual mechanism relevant for estimating the direction of scene-relative motion of independently moving objects during self-motion: observers also rely on prior knowledge about typical object motion, such as typical facing and articulation of humans.

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“…In natural environments, however, we are often confronted with dynamic scenes in which other people walk alongside us. The motion of other walking humans, known as biological motion ( Johansson, 1973 ), introduces noise to the optic flow field, thereby biasing optic flow analysis for heading, the direction of one's self-motion ( Riddell & Lappe, 2017 ; Riddell & Lappe, 2018 ; Riddell, Li, & Lappe, 2019 ; Hülemeier & Lappe, 2020 ; Koerfer & Lappe, 2020 ) and concerning flow parsing, the estimation of independent object motion within a flow field ( Mayer, Riddell, & Lappe, 2021 ). Biological motion consists of limb articulation and its associated translation through space.…”

Section: Introductionmentioning

confidence: 99%

Visual perception of travel distance for self-motion through crowds

Hülemeier

Lappe

2023

Journal of Vision

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Humans can use visual motion to estimate the distance they have traveled. In static environments, optic flow generated by self-motion provides a pattern of expanding motion that is used for the estimation of travel distance. When the environment is populated by other people, their biological motion destroys the one-to-on correspondence between optic flow and travel distance. We investigated how observers estimate travel distance in a crowded environment. In three conditions, we simulated self-motion through a crowd of standing, approaching, or leading point-light walkers. For a standing crowd, optic flow is a veridical signal for distance perception. For an approaching crowd, the visual motion is the sum of the self-motion–induced optic flow and the optic flow produced by the approaching walkers. If only optic flow were to be used, travel distance estimates would be too high because of the approaching direction of the crowd toward the observer. If, on the other hand, cues from biological motion could be used to estimate the speed of the crowd, then the excessive optic from the approaching crowd flow might be compensated. In the leading crowd condition, in which walkers of the crowd keep their distance from the observer as they walk along with the observer, no optic flow is produced. In this condition, travel distance estimation would have to rely solely on biological motion information. We found that distance estimation was quite similar across these three conditions. This suggests that biological motion information can be used (a) to compensate for excessive optic flow in the approaching crowd condition and (b) to generate distance information in the leading crowd condition.

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Pitting optic flow, object motion, and biological motion against each other

Cited by 5 publications

References 57 publications

Life motion signals bias the perception of apparent motion direction

Life motion signals bias the perception of apparent motion direction

Flow parsing and biological motion

Visual perception of travel distance for self-motion through crowds

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