Visual Acceleration Perception for Simple and Complex Motion Patterns

Mueller, Alexandra S.; Timney, Brian

doi:10.1371/journal.pone.0149413

Cited by 19 publications

(14 citation statements)

References 61 publications

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“…Also the acceleration errors made by our participants tended to be smaller than those reported in several studies dealing with detection or discrimination of random accelerations ( Gottsdanker et al, 1961 ; Calderone and Kaiser, 1989 ; Werkhoven et al, 1992 ; Brouwer et al, 2002 ; Watamaniuk and Heinen, 2003 ; Mueller and Timney, 2016 ). Detection thresholds and Weber fractions vary widely across studies, but they are generally very high.…”

Section: Discussioncontrasting

confidence: 61%

Rolling Motion Along an Incline: Visual Sensitivity to the Relation Between Acceleration and Slope

et al. 2018

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People easily intercept a ball rolling down an incline, despite its acceleration varies with the slope in a complex manner. Apparently, however, they are poor at detecting anomalies when asked to judge artificial animations of descending motion. Since the perceptual deficiencies have been reported in studies involving a limited visual context, here we tested the hypothesis that judgments of naturalness of rolling motion are consistent with physics when the visual scene incorporates sufficient cues about environmental reference and metric scale, roughly comparable to those present when intercepting a ball. Participants viewed a sphere rolling down an incline located in the median sagittal plane, presented in 3D wide-field virtual reality. In different experiments, either the slope of the plane or the sphere acceleration were changed in arbitrary combinations, resulting in a kinematics that was either consistent or inconsistent with physics. In Experiment 1 (slope adjustment), participants were asked to modify the slope angle until the resulting motion looked natural for a given ball acceleration. In Experiment 2 (acceleration adjustment), instead, they were asked to modify the acceleration until the motion on a given slope looked natural. No feedback about performance was provided. For both experiments, we found that participants were rather accurate at finding the match between slope angle and ball acceleration congruent with physics, but there was a systematic effect of the initial conditions: accuracy was higher when the participants started the exploration from the combination of slope and acceleration corresponding to the congruent conditions than when they started far away from the congruent conditions. In Experiment 3, participants modified the slope angle based on an adaptive staircase, but the target never coincided with the starting condition. Here we found a generally accurate performance, irrespective of the target slope. We suggest that, provided the visual scene includes sufficient cues about environmental reference and metric scale, joint processing of slope and acceleration may facilitate the detection of natural motion. Perception of rolling motion may rely on the kind of approximate, probabilistic simulations of Newtonian mechanics that have previously been called into play to explain complex inferences in rich visual scenes.

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Section: Discussioncontrasting

confidence: 61%

Rolling Motion Along an Incline: Visual Sensitivity to the Relation Between Acceleration and Slope

et al. 2018

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“…Whilst there appears to be a consensus on the difficulty of acceleration discrimination, estimates of how large the speed change needs to be for the acceleration to be visible varies greatly between studies, anywhere from a 25% to 3 times increase in speed [36,37,39,40,43,44]. It is also important to note that these studies were looking at acceleration discrimination, with the majority of using constant acceleration in their stimuli.…”

Section: Discussionmentioning

confidence: 99%

Speed change discrimination for motion in depth using constant world and retinal speeds

2019

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Motion at constant speed in the world maps into retinal motion very differently for lateral motion and motion in depth. The former is close to linear, for the latter, constant speed objects accelerate on the retina as they approach. Motion in depth is frequently studied using speeds that are constant on the retina, and are thus not consistent with real-world constant motion. Our aim here was to test whether this matters: are we more sensitive to real-world motion? We measured speed change discrimination for objects undergoing accelerating retinal motion in depth (consistent with constant real-world speed), and constant retinal motion in depth (consistent with real-world deceleration). Our stimuli contained both looming and binocular disparity cues to motion in depth. We used a speed change discrimination task to obtain thresholds for conditions with and without binocular and looming motion in depth cues. We found that speed change discrimination thresholds were similar for accelerating retinal speed and constant retinal speed and were notably poor compared to classic speed discrimination thresholds. We conclude that the ecologically valid retinal acceleration in our stimuli neither helps, nor hinders, our ability to make judgements in a speed change discrimination task.

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“…Additionally, neurons in MT are sensitive in aggregate to acceleration, despite the sensitivity of individual neurons being low (72,73). Likewise, psychophysical experiments reveal that humans are sensitive to optic acceleration (74), particularly in global motion patterns (75), with a frequency response peaking at around 1 Hz (76). Our stimulus contained primarily slow accelerations, well within the limits of sensitivity.…”

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confidence: 74%

Heading Perception Depends on Time-Varying Evolution of Optic Flow

Burlingham

Heeger

2018

Preprint

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There is considerable support for the hypothesis that perception of heading in the presence of rotation is mediated by instantaneous optic flow. This hypothesis, however, has never been tested. We introduce a novel method, termed "non-varying phase motion," for generating a stimulus that conveys a single instantaneous optic flow field, even though the stimulus is presented for an extended period of time. In this experiment, observers viewed stimulus videos and performed a forced choice heading discrimination task. For non-varying phase motion, observers made large errors in heading judgments. This suggests that instantaneous optic flow is insufficient for heading perception in the presence of rotation. These errors were mostly eliminated when the velocity of phase motion was varied over time to convey the evolving sequence of optic flow fields corresponding to a particular heading. This demonstrates that heading perception in the presence of rotation relies on the time-varying evolution of optic flow. We hypothesize that the visual system accurately computes heading, despite rotation, based on optic acceleration, the temporal derivative of optic flow.James Gibson first remarked that the instantaneous motion of points on the retina (Fig. 1a) can be formally described as a two-dimensional field of velocity vectors called the "optic flow field" (or "optic flow") (1). Such optic flow, caused by an observer's movement relative to the environment, conveys information about self-motion and the structure of the visual scene (1-15). When an observer translates in a given direction along a straight path, the optic flow field radiates from a point in the image with zero velocity, or singularity, called the focus of expansion (FOE; Fig. 1b). It is well known that under such conditions, one can accurately estimate one's instantaneous direction of translation or "heading" by simply locating the FOE (see SI Appendix). However, if there is angular rotation in addition to translation (by moving along a curved path or by a head or eye movement), the singularity in the optic flow field will be displaced such that it no longer corresponds to the true heading ( Fig. 1c, d). In this case, if one estimates heading by locating the singularity, the estimate will be biased away from the true heading. This is known as the rotation problem (14).Computer vision researchers and vision scientists have developed a variety of algorithms that accurately and precisely extract observer translation and rotation from optic flow, thereby solving the rotation problem. Nearly all of these rely on the instantaneous optic flow field (4, 9,(16)(17)(18)(19)(20)(21)(22)(23)(24)(25) with few exceptions (26-28). However, it is unknown whether these algorithms are commensurate with the neural computations underlying heading perception.The consensus of opinion in the experimental literature is that human observers can estimate heading (29, 30) from the instantaneous optic flow field, in the absence of additional information (5, 10,15,(31)(32)(33). Even so, there...

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Visual Acceleration Perception for Simple and Complex Motion Patterns

Cited by 19 publications

References 61 publications

Rolling Motion Along an Incline: Visual Sensitivity to the Relation Between Acceleration and Slope

Rolling Motion Along an Incline: Visual Sensitivity to the Relation Between Acceleration and Slope

Speed change discrimination for motion in depth using constant world and retinal speeds

Heading Perception Depends on Time-Varying Evolution of Optic Flow

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