A reexamination of the size–weight illusion induced by visual size cues

Kawai, Shinya; Henigman, Frank; MacKenzie, Christine L.; Kuang, Alex B.; Faust, Paul H.

doi:10.1007/s00221-006-0803-1

Cited by 26 publications

(25 citation statements)

References 53 publications

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“…A reduced SWI in schizophrenic patients also fits with emerging research indicating a specific deficit in multisensory integration in this population (de Gelder et al, 2003; de Gelder et al, 2005; de Jong et al, 2009; Ross et al, 2007), as the SWI is strongest when both visual and tactile cues are presented (Ellis and Lederman, 1993; Kawai et al, 2007). …”

Section: Discussionsupporting

confidence: 85%

Superior size–weight illusion performance in patients with schizophrenia: Evidence for deficits in forward models

Williams¹,

Ramachandran²,

Hubbard³

et al. 2010

Schizophrenia Research

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When non-psychiatric individuals compare the weights of two similar objects of identical mass, but of different sizes, the smaller object is often perceived as substantially heavier. This sizeweight illusion (SWI) is thought to be generated by a violation of the common expectation that the large object will be heavier, possibly via a mismatch between an efference copy of the movement and the actual sensory feedback received. As previous research suggests patients with schizophrenia have deficits in forward model/efference copy mechanisms, we hypothesized that schizophrenic patients would show a reduced SWI. The current study compared the strength of the SWI in schizophrenic patients to matched non-psychiatric participants; weight discrimination for same-sized objects was also assessed. We found a reduced SWI for schizophrenic patients, which resulted in better (more veridical) weight discrimination performance on illusion trials compared to non-psychiatric individuals. This difference in the strength of the SWI persisted when groups were matched for weight discrimination performance. The current findings are consistent with a dysfunctional forward model mechanism in this population. Future studies to elucidate the locus of this impairment using variations on the current study are also proposed.

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Section: Discussionsupporting

confidence: 85%

Superior size–weight illusion performance in patients with schizophrenia: Evidence for deficits in forward models

Williams¹,

Ramachandran²,

Hubbard³

et al. 2010

Schizophrenia Research

View full text Add to dashboard Cite

show abstract

“…In that condition, differences in estimated weight could only be attributed to differences in the visual appearance of the objects. That finding has been confirmed by further studies (Kawai, Henigman, Mackenzie, Kuang, & Faust, 2007). The illusory difference is in the opposite direction to the difference in the assumption made by Kozhevnikov and Hegarty (2001): Larger objects tend to be perceived as lighter, not heavier, than smaller ones.…”

Section: Displacement (Representational Momentum)mentioning

confidence: 53%

The impetus theory in judgments about object motion: A new perspective

White

2012

Psychon Bull Rev

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Several tendencies found in explicit judgments about object motion have been interpreted as evidence that people possess a naive theory of impetus. The theory states that objects that are caused to move by other objects acquire force that determines the kind of motion exhibited by the object, and that this force gradually dissipates over time. I argue that the findings can better be understood as manifestations of a general understanding of externally caused motion based on experiences of acting on objects. Experiences of acting on objects yield the idea that properties of the cause of motion are transmitted to the effect object. This idea functions as a heuristic for explicit predictions of object motion under conditions of uncertainty. This accounts not only for the findings taken as evidence for the impetus theory, but also for several findings that fall outside the scope of the impetus theory. It has also been claimed that judgments about the location at which a moving object disappeared are influenced by the impetus theory. I argue that these judgments are better explained in a different way, as best-guess extrapolations made by the visual system as a practical guide to interactions with the object, such as interception.

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“…To obtain a measure of how susceptible an individual was to perceive an illusion, we followed the procedure described by Kawai et al (2007) and first computed the percentage of possible responses (e.g., heavier, similar, and lighter) for each size (e.g., 50 % heavier, 25 % lighter, and 25 % same for the 5.5 cm box). These individual percentages were then averaged across subjects (i.e., mean of % heavier, mean of % lighter, and mean of % same) for each comparison box (see Fig.…”

Section: Measuring the Frequency Of The Size-weight Illusionmentioning

confidence: 99%

The integration of size and weight cues for perception and action: evidence for a weight–size illusion

2012

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Humans routinely estimate the size and weight of objects. Yet, when lifting two objects of equal weight but different size, they often perceive the smaller object as being heavier. This size-weight illusion (SWI) is known to have a lesser effect on motor control of object lifting. How the nervous system combines "weight" and "size" cues with prior experience and whether these cues are differentially integrated for perception and sensorimotor action is still not fully understood. Therefore, we assessed not only whether the experience of size biases weight perception, but also if experience of weight biases the size perception of objects. Further, to investigate differences between perceptual and motor systems for cue-experience integration, participants haptically explored the weight of an object with one hand and then shaped the aperture of their other hand to indicate its perceived size. Results-First, next to a SWI, healthy adults (N = 21) perceived lighter objects as being smaller and heavier objects as being larger, demonstrating a weight-size illusion (WSI). Second, participants were more susceptible to either the SWI or WSI. Third, aperture of the non-exploring hand was scaled to perceived weight and not to physical size. Hand openings were consistently smaller than physical size, with SWI-sensitive participants being significantly more affected than WSI-sensitive subjects. We conclude: first, both size and weight perceptions are biased by prior experience. Weight perception is biased by expectations of size, while size perception is influenced by the expectancy of weight. Second, humans have the tendency to use one cue predominantly for both types of perception. Third, combining perceived weight with expected size influenced hand motor control, while online haptic feedback was largely ignored. Finally, we present a processing model underlying the size-weight cue integration for the perceptual and motor system.

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A reexamination of the size–weight illusion induced by visual size cues

Cited by 26 publications

References 53 publications

Superior size–weight illusion performance in patients with schizophrenia: Evidence for deficits in forward models

Superior size–weight illusion performance in patients with schizophrenia: Evidence for deficits in forward models

The impetus theory in judgments about object motion: A new perspective

The integration of size and weight cues for perception and action: evidence for a weight–size illusion

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