Perception of coherent motion, biological motion and form-from-motion under dim-light conditions

Department of Psychology, Vanderbilt Vision Research Center, Vanderbilt University, Nashville, TN 37240, USA.
Vision Research (Impact Factor: 2.38). 12/1999; 39(22):3721-7. DOI: 10.1016/S0042-6989(99)00084-X
Source: PubMed

ABSTRACT Three experiments investigated several aspects of motion perception at high and low luminance levels. Detection of weak coherent motion in random dot cinematograms was unaffected by light level over a range of dot speeds. The ability to judge form from motion was, however, impaired at low light levels, as was the ability to discriminate normal from phase-scrambled biological motion sequences. The difficulty distinguishing differential motions may be explained by increased spatial pooling at low light levels.

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    • "Psychophysical research has also uncovered a considerable number of other differences in the way we perceive OR and NOR motion. Direction discrimination thresholds (Beardsley & Vaina, 2008; Linares, Motoyoshi, & Nishida, 2012; Snowden, 1992), displacement thresholds (Lappin, Donnelly, & Kojima, 2001; Legge & Campbell, 1981; Murakami, 2004; Palmer, 1986; Sokolov & Pavlova , 2006; Whitaker & MacVeigh, 1990) and reaction times (Smeets & Brenner, 1994) are lower for OR than for NOR motion, and changes in contrast (Grossman & Blake, 1999; Shioiri et al., 2002), spatial frequency (Shioiri et al., 2002) and stimulus size (Mestre, Masson, & Stone, 2001; Murakami & Shimojo, 1996; Nawrot & Sekuler, 1990) affect OR and NOR motion perception differently . Other differences occur during binocular rivalry – if one eye is presented with an OR motion stimulus and the other with NOR motion, the former becomes the dominant percept (e.g. "
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    ABSTRACT: In two experiments, we demonstrate a misperception of the velocity of a random-dot stimulus moving in the presence of a static line oriented obliquely to the direction of dot motion. As shown in previous studies, the perceived direction of the dots is shifted away from the orientation of the static line, with the size of the shift varying as a function of line orientation relative to dot direction (the statically-induced direction illusion, or 'SDI'). In addition, we report a novel effect - that perceived speed also varies as a function of relative line orientation, decreasing systematically as the angle is reduced from 90 to 0°. We propose that these illusions both stem from the differential processing of object-relative and non-object-relative component velocities, with the latter being perceptually underestimated with respect to the former by a constant ratio. Although previous proposals regarding the SDI have not allowed quantitative accounts, we present a unified formal model of perceived velocity (both direction and speed) with the magnitude of this ratio as the only free parameter. The model was successful in accounting for the angular repulsion of motion direction across line orientations, and in predicting the systematic decrease in perceived velocity as the line's angle was reduced. Although fitting for direction and speed produced different best-fit values of the ratio of underestimation of non-object-relative motion compared to object-relative motion (with the ratio for speed being larger than that for direction) this discrepancy may be due to differences in the psychophysical procedures for measuring direction and speed.
    Vision research 08/2013; 92. DOI:10.1016/j.visres.2013.08.010 · 2.38 Impact Factor
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    • "Completion of the biological motion task and the two global motion tasks took about half an hour. Apparatus and stimuli Biological motion A detailed description of the stimuli and procedure has been reported elsewhere (Freire, Lewis, Maurer & Blake, 2006; Grossman & Blake, 1999). Briefly, video recordings were made of an adult engaged in a variety of familiar activities, including running, kicking, climbing, throwing , and jumping. "
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    ABSTRACT: Patients deprived of visual experience during infancy by dense bilateral congenital cataracts later show marked deficits in the perception of global motion (dorsal visual stream) and global form (ventral visual stream). We expected that they would also show marked deficits in sensitivity to biological motion, which is normally processed in the superior temporal sulcus via input from both the dorsal and ventral streams. When tested on the same day for sensitivity to biological motion and to global motion at two speeds (4 and 18° s(-1)), patients, as expected, displayed a large deficit in processing global motion at both speeds. Surprisingly, they performed normally in discriminating biological motion from scrambled displays, tolerating as much noise as their age-matched controls. Networks bypassing damaged portions of the dorsal and the ventral streams must mediate the spared sensitivity to biological motion after early visual deprivation.
    Developmental Science 07/2012; 15(4):474-81. DOI:10.1111/j.1467-7687.2012.01145.x · 3.89 Impact Factor
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    • "In contrast, biological motion, the perception of which also depends on the spatial organization of the relevant motion tokens (e.g. Grossman & Blake, 1999), activates in addition a network of areas in the extrastriate cortex involving primarily a region on the ventral bank of the occipital extent of the superior-temporal sulcus (STS; Grossman, Donnelly, Price, Pickers, Morgan, Neighbor & Blake, 2000), an area that receives input from both the dorsal and ventral streams (e.g. Schenk, Mai, Ditterich & Zihl, 2000). "
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    ABSTRACT: We used a staircase procedure to test sensitivity to (1) global motion in random-dot kinematograms moving at 4° and 18° s(-1) and (2) biological motion. Thresholds were defined as (1) the minimum percentage of signal dots (i.e. the maximum percentage of noise dots) necessary for accurate discrimination of upward versus downward motion or (2) the maximum percentage of noise dots tolerated for accurate discrimination of biological from non-biological motion. Subjects were adults and children aged 6-8, 9-11, and 12-14 years (n = 20 per group). Contrary to earlier research, results revealed a similar, long developmental trajectory for sensitivity to global motion at both slower and faster speeds and for biological motion. Thresholds for all three tasks improved monotonically between 6 and 14 years of age, at which point they were adult-like. The results suggest that the extrastriate mechanisms that integrate local motion cues over time and space take many years to mature.
    Developmental Science 11/2011; 14(6):1330-9. DOI:10.1111/j.1467-7687.2011.01078.x · 3.89 Impact Factor
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