Geometric and Neural Models of Object Perception

Kellman, Philip J.; Guttman, Sharon E.; Wickens, Thomas D.

doi:10.1016/s0166-4115(01)80027-3

Cited by 41 publications

(58 citation statements)

References 59 publications

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“…This computation helps the visual system to derive a fast and "dirty" representation of objects (Rensink & Enns, 1998). The line may not be accessible consciously, however, consistent with the distinction made by Kellman et al (2001) that not all interpolated contours reach consciousness. What we propose in addition is that the binding of this occluded line with visible contours is a necessary step for the occluded contour to reach consciousness.…”

Section: Discussionmentioning

confidence: 97%

“…However, one of the main differences between the two series of experiments is that the studies showing an influence of depth information have typically explored the conscious perception of occluding contours. In contrast, studies suggesting early completion (Giersch et al, 2000;Kellman et al, 2001;Rensink & Enns, 1998) have explored the influence of unconsciously perceived contours on performance. Thus, as suggested by Kellman et al (2001, pp.…”

Section: Discussionmentioning

confidence: 99%

“…For example, the role of depth and the contextual layout of stimuli may come about because of higher-level processes that utilise but also modulate the information computed at the earlier stage. Within this second stage, occluded contours may not be treated in the same manner as visible contours, leading to some differences in tasks requiring responses to both types of stimuli (Kellman, Guttman, & Wickens, 2001). This proposal was put to a more detailed test here.…”

Section: Completing Occluded Contoursmentioning

confidence: 99%

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A two-stage account of computing and binding occluded and visible contours: Evidence from visual agnosia and effects of lorazepam

Giersch

Humphreys

Barthaud

et al. 2006

Cognitive Neuropsychology

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Previous work has shown that HJA, a patient suffering from visual agnosia, can complete occluded contours whilst being impaired at assigning contours to foreground and background figures (Giersch, Humphreys, Boucart, & Kovacs, 2000). Here we tested whether completed contours are automatically bound with visible contours, after being derived from them. HJA, lorazepam-treated and nontreated healthy participants were asked to match a first reference line with an equal or longer line of identical orientation included in one of two lateral figures. The target line was in the foreground or the background of the figures. The distractor picture included two short collinear line-segments belonging to two different figures, so that participants had to process the occluded parts to discriminate the target from the distractor line. When the target line was in the background, both HJA and lorazepam-treated participants were faster when the length of the reference line corresponded to the length of the occluded part of the target line, relative to when it corresponded to the length of the occluded part plus a visible contour. In contrast, control participants tended to show an advantage for matching a reference line whose length was the same as the visible contours plus the occluded part. However, when the stimuli were displayed for 50 ms only and then masked, controls showed the same results as HJA. These results suggest that responses in the matching tasks are biased by the existence of an early completed occluded line that remains isolated from real contours.

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Section: Completing Occluded Contoursmentioning

confidence: 99%

See 1 more Smart Citation

A two-stage account of computing and binding occluded and visible contours: Evidence from visual agnosia and effects of lorazepam

Giersch

Humphreys

Barthaud

et al. 2006

Cognitive Neuropsychology

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“…Fish behaved as if they were experiencing visual completion of the partly occluded stimuli (Sovrano and Bisazza, 2008). The perception of amodal completion and the perception of subjective contours both seem to use the same basic mechanisms to deal with occlusion problems (Kellman and Shipley, 1991; Kellman et al, 2001, 2005). …”

Section: Discussionmentioning

confidence: 99%

The brain creates illusions not just for us: sharks (Chiloscyllium griseum) can â€œsee the magicâ€ as well

Fuss

Bleckmann

Schluessel

2014

Front. Neural Circuits

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Bamboo sharks (Chiloscyllium griseum) were tested for their ability to perceive subjective and illusionary contours as well as line length illusions. Individuals were first trained to differentiate between squares, triangles, and rhomboids in a series of two alternative forced-choice experiments. Transfer tests then elucidated whether Kanizsa squares and triangles, grating gaps and phase shifted abutting gratings were also perceived and distinguished. The visual systems of most vertebrates and even invertebrates perceive illusionary contours despite the absence of physical luminance, color or textural differences. Sharks are no exception to the rule; all tasks were successfully mastered within 3–24 training sessions, with sharks discriminating between various sets of Kanizsa figures and alternative stimuli, as well as between subjective contours in >75% of all tests. However, in contrast to Kanizsa figures and subjective contours, sharks were not deceived by Müller-Lyer (ML) illusions. Here, two center lines of equal length are comparatively set between two arrowheads or –tails, in which case the line featuring the two arrow tails appears to be longer to most humans, primates and birds. In preparation for this experiment, lines of varying length, and lines of unequal length randomly featuring either two arrowheads or -tails on their ends, were presented first. Both sets of lines were successfully distinguished by most sharks. However, during presentation of the ML illusions sharks failed to succeed and succumbed either to side preferences or chose according to chance.

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“…The identity hypothesis suggests a local-based computational process by which interpolation processes operate (for more details, see Kellman, 2003;Kellman, Guttman, & Wickens, 2001;Kellman & Shipley, 1991). Specifically, tangent discontinuity, places at intersections or junctions in the stimuli where contours have no unique orientation, have been defined as points at which computations subserving interpolation begin.…”

Section: Discussionmentioning

confidence: 99%

Developmental trends in interpolation and its spatial constraints: A comparison of subjective and occluded contours

Hadad

Maurer

Lewis

2015

Atten Percept Psychophys

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We examined interpolation in 6-and 9-year-old children and in adults, in the two most common forms of fragmentation: subjective and partially occluded contours. Experiment 1 examined the effects on adults' interpolation of contour geometry, specifically, the effect of a scale-dependent factor (i.e., retinal size) and a scale-independent factor (i.e., support ratio). For both subjective and partially occluded contours, interpolation was affected more by support ratio than absolute size. However, subjective contours were less precisely interpolated and their interpolation was affected more by support ratio than was the case for partial occlusion. Experiment 2 used a subset of retinal size and support ratio levels in children and adults. Interpolation of both subjective and occluded contours improved significantly with age, with the two types of contours equally affected by spatial constraints during early childhood. However, while interpolation of occluded contours became more precise with age and less dependent on support ratio by adulthood, interpolation of subjective contours was less improved and became even more tied to support ratio in adulthood. The implications of these differential age-related changes in the spatial constraints on interpolation of the two types of contours for the mechanisms of perceptual completion are discussed.

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Geometric and Neural Models of Object Perception

Cited by 41 publications

References 59 publications

A two-stage account of computing and binding occluded and visible contours: Evidence from visual agnosia and effects of lorazepam

A two-stage account of computing and binding occluded and visible contours: Evidence from visual agnosia and effects of lorazepam

The brain creates illusions not just for us: sharks (Chiloscyllium griseum) can â€œsee the magicâ€ as well

Developmental trends in interpolation and its spatial constraints: A comparison of subjective and occluded contours

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Geometric and Neural Models of Object Perception

Cited by 41 publications

References 59 publications

A two-stage account of computing and binding occluded and visible contours: Evidence from visual agnosia and effects of lorazepam

A two-stage account of computing and binding occluded and visible contours: Evidence from visual agnosia and effects of lorazepam

The brain creates illusions not just for us: sharks (Chiloscyllium griseum) can â€œsee the magicâ€ as well

Developmental trends in interpolation and its spatial constraints: A comparison of subjective and occluded contours

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The brain creates illusions not just for us: sharks (Chiloscyllium griseum) can â€œsee the magicâ€ as well