The effects of instrumental action on perceptual hand maps

Longo, Matthew R.

doi:10.1007/s00221-018-5360-x

Cited by 20 publications

(21 citation statements)

References 53 publications

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“…These maps showed large and highly stereotyped distortions, specifically: (1) overall overestimation of hand width, (2) overall underestimation of finger length, and (3) a radial-ulnar gradient with finger length underestimation increasing from the thumb to the little finger. This basic pattern has been found in numerous subsequent studies, both from my lab (e.g., Longo, 2014Longo, , 2015aLongo, , 2017aLongo, , 2018Longo, Long, & Haggard, 2012;Longo, Mattioni, & Ganea, 2015;Ganea & Longo, 2017;Tamè, Bumpus, Linkenauger, & Longo, 2017) and other labs (e.g., Cocchini, Galligan, Mora, & Kuhn, 2018;Coelho, Zaninelli, & Gonzalez, 2017;Coelho et al, 2019;Ferrè, Vagnoni, & Haggard, 2013;Lopez, Schreyer, Preuss, & Mast, 2012;Medina & Duckett, 2017;Peviani & Bottini, 2018;Saulton, Dodds, Bülthoff, & de la Rosa, 2015;Saulton, Longo, Wong, Bülthoff, & de la Rosa, 2016;Saulton, Bülthoff, & de la Rosa, 2017;Stone, Keizer, & Dijkerman, 2018). In contrast, when participants judge whether hand images are fatter or thinner than their own hand, they show no systematic biases (Longo, 2015d;, 2012b.…”

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confidence: 70%

Sex differences in perceptual hand maps: A meta-analysis

Longo

2019

Acta Psychologica

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A large body of research has suggested that localisation of the hand in external space relies on distorted representations of the hand. We developed a paradigm for measuring implicit perceptual maps of the hand (Longo & Haggard, 2010, Proc Natl Acad Sci USA, 107, 11727-11732), which show systematic deviation from actual hand shape, including overestimation of hand width and underestimation of finger length. Recently, Coelho and Gonzalez (in press, Psychol Res) reported sex differences in these perceptual hand maps, with women showing greater overestimation of hand width, but less underestimation of finger length than men. In the current study, I conducted a meta-analysis of 19 experiments using this paradigm by myself and my colleagues. The results replicated the sex differences reported by Coelho and Gonzalez. Importantly, however, these sex differences were not apparent when actual hand size was included as a covariate in analyses, suggesting that they may, at least in part, be due to women having smaller hands on average than men.

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confidence: 70%

Sex differences in perceptual hand maps: A meta-analysis

Longo

2019

Acta Psychologica

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“…The slight underestimates of hand width (between the primary knuckles for the index and little fingers) seen in our control groups are in contrast to the overestimation reported by Longo and colleagues (Longo andHaggard 2010, 2012;Ganea and Longo 2017). They asked participants to use (or to guide) a long-thin pointer to mark a position on a surface a few centimetres above the hand, and to move it to the lateral edge of the board between trials.…”

Section: Reporting Landmark Positions On the Hand Reflects Experiencecontrasting

confidence: 56%

“…In Experiment 1B, participants reported the location of landmarks on their unseen hands. The controls showed the previously described severe underestimation of finger lengths (Longo andHaggard 2010, 2012). We did not, however, reproduce the graduated and increasing underestimation from thumb to little finger that Longo and colleagues report, possibly due to a difference in instructions.…”

Section: Reporting Landmark Positions On the Hand Reflects Experiencementioning

confidence: 55%

“…Experiments 1 and 2 required conscious judgements about body size and shape, or the location of landmarks on the hand. We found strikingly different degrees of distortion between controls, and the participants, suggesting that the visual representation of hand shape may be quite distinct from metrical knowledge (Longo andHaggard 2010, 2012). Both IW, who has lived nearly 50 years without large fibre somatosensation from age 19, and KS, who was born and has lived 40 years without both large and small fibre somatic input from her body, performed these tasks well.…”

Section: Discussionmentioning

confidence: 75%

“…This suggests that the task is heavily reliant on a visual (KS and IW) or visuo-somatic representation (controls). Longo andHaggard (2010, 2012) have suggested that the "metrical" graduated distortion might be related to the different density of cutaneous receptors across the hand. Since the conscious representation of body shape is normally multi-modal, integrating visual and somatosensory inputs, the contribution of these two sources might alter across the cortical hand representation, affecting overestimation in their judgements.…”

Section: Reporting Landmark Positions On the Hand Reflects Experiencementioning

confidence: 99%

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Perception of body shape and size without touch or proprioception: evidence from individuals with congenital and acquired neuropathy

et al. 2021

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The degree to which mental representations of the body can be established and maintained without somatosensory input remains unclear. We contrast two “deafferented” adults, one who acquired large fibre sensory loss as an adult (IW) and another who was born without somatosensation (KS). We compared their responses to those of matched controls in three perceptual tasks: first accuracy of their mental image of their hands (assessed by testing recognition of correct hand length/width ratio in distorted photographs and by locating landmarks on the unseen hand); then accuracy of arm length judgements (assessed by judgement of reaching distance), and finally, we tested for an attentional bias towards peri-personal space (assessed by reaction times to visual target presentation). We hypothesised that IW would demonstrate responses consistent with him accessing conscious knowledge, whereas KS might show evidence of responses dependent on non-conscious mechanisms. In the first two experiments, both participants were able to give consistent responses about hand shape and arm length, but IW displayed a better awareness of hand shape than KS (and controls). KS demonstrated poorer spatial accuracy in reporting hand landmarks than both IW and controls, and appears to have less awareness of her hands. Reach distance was overestimated by both IW and KS, as it was for controls; the precision of their judgements was slightly lower than that of the controls. In the attentional task, IW showed no reaction time differences across conditions in the visual detection task, unlike controls, suggesting that he has no peri-personal bias of attention. In contrast, KS did show target location-dependent modulation of reaction times, when her hands were visible. We suggest that both IW and KS can access a conscious body image, although its accuracy may reflect their different experience of hand action. Acquired sensory loss has deprived IW of any subconscious body awareness, but the congenital absence of somatosensation may have led to its partial replacement by a form of visual proprioception in KS.

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The signing body: extensive sign language practice shapes the size of hands and face

et al. 2021

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The representation of the metrics of the hands is distorted, but is susceptible to malleability due to expert dexterity (magicians) and long-term tool use (baseball players). However, it remains unclear whether modulation leads to a stable representation of the hand that is adopted in every circumstance, or whether the modulation is closely linked to the spatial context where the expertise occurs. To this aim, a group of 10 experienced Sign Language (SL) interpreters were recruited to study the selective influence of expertise and space localisation in the metric representation of hands. Experiment 1 explored differences in hands’ size representation between the SL interpreters and 10 age-matched controls in near-reaching (Condition 1) and far-reaching space (Condition 2), using the localisation task. SL interpreters presented reduced hand size in near-reaching condition, with characteristic underestimation of finger lengths, and reduced overestimation of hands and wrists widths in comparison with controls. This difference was lost in far-reaching space, confirming the effect of expertise on hand representations is closely linked to the spatial context where an action is performed. As SL interpreters are also experts in the use of their face with communication purposes, the effects of expertise in the metrics of the face were also studied (Experiment 2). SL interpreters were more accurate than controls, with overall reduction of width overestimation. Overall, expertise modifies the representation of relevant body parts in a specific and context-dependent manner. Hence, different representations of the same body part can coexist simultaneously.

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The effects of instrumental action on perceptual hand maps

Cited by 20 publications

References 53 publications

Sex differences in perceptual hand maps: A meta-analysis

Sex differences in perceptual hand maps: A meta-analysis

Perception of body shape and size without touch or proprioception: evidence from individuals with congenital and acquired neuropathy

The signing body: extensive sign language practice shapes the size of hands and face

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