Grasping follows Weber's law: How to use response variability as a proxy for JND

Bhatia, Kriti; Löwenkamp, Christian; Franz, Volker H.

doi:10.1167/jov.22.12.13

Cited by 9 publications

(2 citation statements)

References 65 publications

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“…Here we found that actions obey Weber's law. The SD of the final inter-finger separation increased as a function of the inter-target distance, with a slope ranging from 0.012 to 0.038, in line with the classic and modern literature on Weber's law (e.g., Bhatia et al, 2022;Derzsi & Volcic, 2023;Fechner, 1860;Hesse et al, 2021;McKee & Welch, 1992;Teghtsoonian, 1971).…”

Section: Discussionsupporting

confidence: 83%

“…However, it should be noted that recent studies have suggested that SD MGA may not accurately reflect the precision with which visual size is discriminated. In particular, Bhatia et al (2022) demonstrated that using MGA as a proxy for the corresponding final estimation response can erroneously mask Weber's law because the response function of MGA is non-linear. When this non-linear scaling is appropriately considered, Weber's law can be detected even in grasping movements.…”

Section: Discussionmentioning

confidence: 99%

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Actions obey Weber’s law when precision is evaluated at goal attainment

Camponogara,

Volcic

2024

Preprint

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Weber’s law, the psychophysical principle stating that the just noticeable difference (JND), which is inversely related to sensory precision, increases proportionally with the magnitude of a stimulus, impacts all domains of human perception, but it is violated in visually guided grasping actions. The underlying reasons for this dissociation between perception and action are still debated, and various hypotheses have been put forward, including a different coding of visual size information for perception and action, the use of positional information to guide grasping, biomechanical factors, or sensorimotor calibration. To contrast these hypotheses, we investigated Weber’s law in a new action task, the two-finger pointing task. Participants reached and touched two targets positioned at different distances apart by using their index finger and thumb. Consistent with Weber’s law, we found that the standard deviation (SD) of the final inter-finger separation, serving as a measure analogous to the JND, increased with larger inter-target distances. These findings suggest that, when considering measures strongly related with the attainment of the action goal, Weber’s law is regularly at play.

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Section: Discussionsupporting

confidence: 83%

Section: Discussionmentioning

confidence: 99%

Actions obey Weber’s law when precision is evaluated at goal attainment

Camponogara,

Volcic

2024

Preprint

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Modal and amodal cognition: an overarching principle in various domains of psychology

Kaup,

Ulrich,

Bausenhart

et al. 2023

Psychological Research

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Accounting for how the human mind represents the internal and external world is a crucial feature of many theories of human cognition. Central to this question is the distinction between modal as opposed to amodal representational formats. It has often been assumed that one but not both of these two types of representations underlie processing in specific domains of cognition (e.g., perception, mental imagery, and language). However, in this paper, we suggest that both formats play a major role in most cognitive domains. We believe that a comprehensive theory of cognition requires a solid understanding of these representational formats and their functional roles within and across different domains of cognition, the developmental trajectory of these representational formats, and their role in dysfunctional behavior. Here we sketch such an overarching perspective that brings together research from diverse subdisciplines of psychology on modal and amodal representational formats so as to unravel their functional principles and their interactions.

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Grasping tiny objects

Giesel,

De Filippi,

Hesse

2024

Psychological Research

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In grasping studies, maximum grip aperture (MGA) is commonly used as an indicator of the object size representation within the visuomotor system. However, a number of additional factors, such as movement safety, comfort, and efficiency, might affect the scaling of MGA with object size and potentially mask perceptual effects on actions. While unimanual grasping has been investigated for a wide range of object sizes, so far very small objects (<5 mm) have not been included. Investigating grasping of these tiny objects is particularly interesting because it allows us to evaluate the three most prominent explanatory accounts of grasping (the perception-action model, the digits-in-space hypothesis, and the biomechanical account) by comparing the predictions that they make for these small objects. In the first experiment, participants ($$N=26$$ N = 26 ) grasped and manually estimated the height of square cuboids with heights from 0.5 to 5 mm. In the second experiment, a different sample of participants ($$N=24$$ N = 24 ) performed the same tasks with square cuboids with heights from 5 to 20 mm. We determined MGAs, manual estimation apertures (MEA), and the corresponding just-noticeable differences (JND). In both experiments, MEAs scaled with object height and adhered to Weber’s law. MGAs for grasping scaled with object height in the second experiment but not consistently in the first experiment. JNDs for grasping never scaled with object height. We argue that the digits-in-space hypothesis provides the most plausible account of the data. Furthermore, the findings highlight that the reliability of MGA as an indicator of object size is strongly task-dependent.

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Grasping follows Weber's law: How to use response variability as a proxy for JND

Cited by 9 publications

References 65 publications

Actions obey Weber’s law when precision is evaluated at goal attainment

Actions obey Weber’s law when precision is evaluated at goal attainment

Modal and amodal cognition: an overarching principle in various domains of psychology

Grasping tiny objects

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