title: Perceiving and acting upon weight illusions in the absence of somatosensory information.
abstract: When lifting novel objects, individuals' fingertip forces are influenced by a variety of cues such as volume and apparent material. This means that heavy-looking objects tend to be lifted with more force than lighter-looking objects, even when they weigh the same amount as one another. Expectations about object weight based on visual appearance also influence how heavy an object feels when it is lifted. For instance, in the "size-weight illusion," small objects feel heavier than equally weighted large objects. Similarly, in the "material-weight illusion," objects that seem to be made from light-looking materials feel heavier than objects of the same weight that appear to be made from heavy-looking materials. In this study, we investigated these perceptual and sensorimotor effects in IW, an individual with peripheral deafferentation (i.e., a loss of tactile and proprioception feedback). We examined his perceptions of heaviness and fingertip force application over repeated lifts of objects that varied in size or material properties. Despite being able to report real weight differences, IW did not appear to experience the size- or material-weight illusions. Furthermore, he showed no evidence of sensorimotor prediction based on size and material cues. The results are discussed in the context of forward models and their possible influence on weight perception and fingertip force control.
authors: Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom; Department of Psychology, School of Life Sciences, Heriot-Watt University, Edinburgh, United Kingdom; and gav.buckingham@gmail.com.
authors: Gavin
authors: G
authors: Buckingham
authors: Department of Psychology, School of Life Sciences, Heriot-Watt University, Edinburgh, United Kingdom; and.
authors: Elizabeth Evgenia
authors: EE
authors: Michelakakis
authors: Centre of Postgraduate Medical Research and Education, Bournemouth University and Poole Hospital NHS Foundation Trust, Poole, United Kingdom.
authors: Jonathan
authors: J
authors: Cole
mesh_terms: D016022:Case-Control Studies; D056228:Feedback, Sensory; D006801:Humans; D007088:Illusions; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology / Q000502:physiology; D009475:Neurons, Afferent / Q000473:pathology / Q000502:physiology; D020886:Somatosensory Disorders / Q000503:physiopathology*; D055698:Touch Perception; D014892:Weight Perception
keywords: deafferentation; grip force; load force; material-weight illusion; size-weight illusion