The perception of real and illusory motion in schizophrenia

Crawford, Trevor J.; Hamm, Jeff P.; Kean, Matthew; Schmechtig, Anne; Kumari, Veena; Anilkumar, Anantha P.; Ettinger, Ulrich

doi:10.1016/j.neuropsychologia.2010.06.027

Cited by 35 publications

(55 citation statements)

References 38 publications

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“…This is called polarized gamma motion (Kanizsa, 1979), although in similar displays von Grünau and Faubert (1994) referred to this as motion induction. Although the presented object may be of any shape (Kanizsa, 1979), for convenience and to coincide with the current study and recent literature (Christie & Barresi, 2002;Christie & Klein, 2005;Crawford et al, 2010;Crawford, Kean, Klein, & Hamm, 2006;Downing & Treisman, 1997;Hamm et al, 2014;Hamm & Klein, 2002;Hikosaka, Miyauchi, & Shimojo, 1993a, 1993b, 1993cvon Grünau & Faubert, 1994), the object that undergoes illusory motion is referred to as the bar, because this object is generally rectangular with the motion directed along the long axis. The existing object that induces the illusory motion in the bar is referred to as the box, because the inducing object is typically a solid square.…”

Section: Brief Overview Of Illusory Line Motionmentioning

confidence: 97%

“…When a preexisting bar is removed from between two boxes following the flash, the illusory motion of the disappearing bar is also away from the flashed box (Crawford et al, 2010;Hamm et al, 2014). This is unlike polarized gamma motion where the motion is towards the single box when an existing bar is removed in the absence of a flash (Kanizsa, 1979); there may be separate underlying causes behind polarized gamma motion and illusory line motion away from a flash.…”

Section: Brief Overview Of Illusory Line Motionmentioning

confidence: 99%

“…Moreover, ILM has been shown to be weaker in people diagnosed with schizophrenia (Crawford et al, 2010), a disorder long known to be associated with deficits in visual attention (Kraepelin, 1919). Additionally, illusory line motion is reported even in the absence of a box, such as following reflexive gaze orienting (Bavelier et al, 2002) or when attention is direction to a location by auditory or tactile cues (Shimojo et al, 1997).…”

Section: Brief Overview Of Illusory Line Motionmentioning

confidence: 99%

“…If the bar is removed after the flash is over the motion is away from the flash (Crawford et al, 2010;Hamm et al, 2014); however, if the bar is removed during the flash then the motion is towards the flash (Hamm et al, 2014); this is reverse ILM (rILM). While some have suggested that attention may result in prolonging existing visual signals (Schmidt & Klein, 1997), which would bring rILM under an attentional explanation, it does not explain why offset bars produce rILM during the flash but ILM after the flash.…”

Section: Brief Overview Of Illusory Line Motionmentioning

confidence: 99%

“…While individual studies have shown that the illusory motion is away from a bright flash for both onset (Hikosaka et al, 1993c) and offset (Crawford et al, 2010;Hamm et al, 2014) bars, so far it has not been determined whether these illusions are correlated at the individual level. It is possible that onset and offset bars result in illusory motion for entirely different reasons.…”

Section: Brief Overview Of Illusory Line Motionmentioning

confidence: 99%

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Illusory line motion in onset and offset bars

Han

Zhu

Corballis

et al. 2016

Atten Percept Psychophys

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Illusory line motion (ILM) refers to the perception of motion in a bar that is presented all at once next to an inducing stimulus. The experimental methods for producing and quantifying ILM are varied, and the resulting explanations are likewise at odds. The current study examined the explanations for ILM away from the inducing stimulus (bright or dark flash) using bars that either suddenly appear (onset bars) or suddenly disappear (offset bars). Real motion is used to cancel ILM, providing three measures to quantify ILM: the consistency of responding to only ILM in the absence of real motion; the distance between the points of subjective equality between ILM and the real motion; and the area between the curves relating perception of motion to the real and illusory conditions. ILM quantities for onset and offset bars are strongly correlated when the bar change occurs after the flash. However, onset bars presented during the flash do not show any evidence of ILM, whereas offset bars removed during the flash result in reverse ILM (rILM). Moreover, rILM and ILM are not correlated, suggesting they reflect two separate illusions. These results are consistent over the various measures of ILM.Keywords Attention . Illusory line motion . Motion perception Forms of illusory line motion (ILM) have been investigated since the early 1900s. There have been a number of paradigms employed, and the phenomenon has been quantified in different ways. As a result, a range of explanations has been offered. This variety, while providing a rich source of data, presents its own problems. Primarily, the lack of consistency in protocols and measurements makes it difficult to know if the results arising from one study are relevant to a study using different methods or measuring different quantities. One cannot be sure they are examining the same underlying phenomena. What follows is not so much an attempt to determine which explanations of illusory line motion are supported or valid and which can be dismissed or rejected, but rather a presentation that attempts to determine what findings warrant a common explanation and what findings can be argued to be reflective of a different illusory phenomenon. After coverage of the literature illustrating the variations of methods, we focused primarily on illusory line motion that occurs following a brief luminance change and made recommendations with respect to experimental methods, quantification of ILM, and data analyses.

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Section: Brief Overview Of Illusory Line Motionmentioning

confidence: 97%

Section: Brief Overview Of Illusory Line Motionmentioning

confidence: 99%

Section: Brief Overview Of Illusory Line Motionmentioning

confidence: 99%

Section: Brief Overview Of Illusory Line Motionmentioning

confidence: 99%

Section: Brief Overview Of Illusory Line Motionmentioning

confidence: 99%

See 3 more Smart Citations

Illusory line motion in onset and offset bars

Han

Zhu

Corballis

et al. 2016

Atten Percept Psychophys

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show abstract

Computational Models of Hallucinations

Jardri

2012

The Neuroscience of Hallucinations

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Apparent motion perception in patients with paranoid schizophrenia

Sanders

Millas

Heinz

et al. 2012

Eur Arch Psychiatry Clin Neurosci

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Impaired perceptual inference has been suggested to be at the core of positive symptoms in schizophrenia. Apparent motion (AM) is a visual illusion in which perceptual inference gives rise to the experience of a single object moving back and forth when two spatially separated objects are flashed in alternation. Here, we investigated the strength of AM perception in patients with paranoid schizophrenia. Patients were less susceptible to the illusion as indicated by a lower probability of motion perception at the individual's optimal presentation frequency for AM. In addition, the probability of AM perception was inversely related to delusional conviction in the patient group. These results suggest that schizophrenia may be associated with a reduced susceptibility to visual phenomena that commonly rely on perceptual inference.

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The perception of real and illusory motion in schizophrenia

Cited by 35 publications

References 38 publications

Illusory line motion in onset and offset bars

Illusory line motion in onset and offset bars

Computational Models of Hallucinations

Apparent motion perception in patients with paranoid schizophrenia

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