Dataset Information

Does gesture strengthen sensorimotor knowledge of objects? The case of the size-weight illusion.

ABSTRACT: Co-speech gestures have been proposed to strengthen sensorimotor knowledge related to objects' weight and manipulability. This pre-registered study (https://www.osf.io/9uh6q/) was designed to explore how gestures affect memory for sensorimotor information through the application of the visual-haptic size-weight illusion (i.e., objects weigh the same, but are experienced as different in weight). With this paradigm, a discrepancy can be induced between participants' conscious illusory perception of objects' weight and their implicit sensorimotor knowledge (i.e., veridical motor coordination). Depending on whether gestures reflect and strengthen either of these types of knowledge, gestures may respectively decrease or increase the magnitude of the size-weight illusion. Participants (N?=?159) practiced a problem-solving task with small and large objects that were designed to induce a size-weight illusion, and then explained the task with or without co-speech gesture or completed a control task. Afterwards, participants judged the heaviness of objects from memory and then while holding them. Confirmatory analyses revealed an inverted size-weight illusion based on heaviness judgments from memory and we found gesturing did not affect judgments. However, exploratory analyses showed reliable correlations between participants' heaviness judgments from memory and (a) the number of gestures produced that simulated actions, and (b) the kinematics of the lifting phases of those gestures. These findings suggest that gestures emerge as sensorimotor imaginings that are governed by the agent's conscious renderings about the actions they describe, rather than implicit motor routines.

SUBMITTER: Pouw W

PROVIDER: S-EPMC7239830 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Does gesture strengthen sensorimotor knowledge of objects? The case of the size-weight illusion.

Pouw Wim W Wassenburg Stephanie I SI Hostetter Autumn B AB de Koning Bjorn B BB Paas Fred F

Psychological research 20181214 4

Co-speech gestures have been proposed to strengthen sensorimotor knowledge related to objects' weight and manipulability. This pre-registered study (https://www.osf.io/9uh6q/) was designed to explore how gestures affect memory for sensorimotor information through the application of the visual-haptic size-weight illusion (i.e., objects weigh the same, but are experienced as different in weight). With this paradigm, a discrepancy can be induced between participants' conscious illusory perception o ...[more]

PMID: 30552506

Similar Datasets

Project description:The material-weight illusion (MWI) occurs when an object that looks heavy (e.g., stone) and one that looks light (e.g., Styrofoam) have the same mass. When such stimuli are lifted, the heavier-looking object feels lighter than the lighter-looking object, presumably because well-learned priors about the density of different materials are violated. We examined whether a similar illusion occurs when a certain weight distribution is expected (such as the metal end of a hammer being heavier), but weight is uniformly distributed. In experiment 1, participants lifted bipartite objects that appeared to be made of two materials (combinations of stone, Styrofoam, and wood) but were manipulated to have a uniform weight distribution. Most participants experienced an inverted MWI (i.e., the heavier-looking side felt heavier), suggesting an integration of incoming sensory information with density priors. However, a replication of the classic MWI was found when the objects appeared to be uniformly made of just one of the materials ( experiment 2). Both illusions seemed to be independent of the forces used when the objects were lifted. When lifting bipartite objects but asked to judge the weight of the whole object, participants experienced no illusion ( experiment 3). In experiment 4, we investigated weight perception in objects with a nonuniform weight distribution and again found evidence for an integration of prior and sensory information. Taken together, our seemingly contradictory results challenge most theories about the MWI. However, Bayesian integration of competing density priors with the likelihood of incoming sensory information may explain the opposing illusions. NEW & NOTEWORTHY We report a novel weight illusion that contradicts all current explanations of the material-weight illusion: When lifting an object composed of two materials, the heavier-looking side feels heavier, even when the true weight distribution is uniform. The opposite (classic) illusion is found when the same materials are lifted in two separate objects. Identifying the common mechanism underlying both illusions will have implications for perception more generally. A potential candidate is Bayesian inference with competing priors.

Project description:When judging the heaviness of two objects with equal mass, people perceive the smaller and denser of the two as being heavier. Despite the large number of theories, covering bottom-up and top-down approaches, none of them can fully account for all aspects of this size-weight illusion and thus for human heaviness perception. Here we propose a new maximum-likelihood estimation model which describes the illusion as the weighted average of two heaviness estimates with correlated noise: One estimate derived from the object's mass, and the other from the object's density, with estimates' weights based on their relative reliabilities. While information about mass can directly be perceived, information about density will in some cases first have to be derived from mass and volume. However, according to our model at the crucial perceptual level, heaviness judgments will be biased by the objects' density, not by its size. In two magnitude estimation experiments, we tested model predictions for the visual and the haptic size-weight illusion. Participants lifted objects which varied in mass and density. We additionally varied the reliability of the density estimate by varying the quality of either visual (Experiment 1) or haptic (Experiment 2) volume information. As predicted, with increasing quality of volume information, heaviness judgments were increasingly biased towards the object's density: Objects of the same density were perceived as more similar and big objects were perceived as increasingly lighter than small (denser) objects of the same mass. This perceived difference increased with an increasing difference in density. In an additional two-alternative forced choice heaviness experiment, we replicated that the illusion strength increased with the quality of volume information (Experiment 3). Overall, the results highly corroborate our model, which seems promising as a starting point for a unifying framework for the size-weight illusion and human heaviness perception.

Project description:An ongoing issue of interest in second language research concerns what transfers from a speaker's first language to their second. For learners of a sign language, gesture is a potential substrate for transfer. Our study provides a novel test of gestural production by eliciting silent gesture from novices in a controlled environment. We focus on spatial relationships, which in sign languages are represented in a very iconic way using the hands, and which one might therefore predict to be easy for adult learners to acquire. However, a previous study by Marshall and Morgan (2015) revealed that this was only partly the case: in a task that required them to express the relative locations of objects, hearing adult learners of British Sign Language (BSL) could represent objects' locations and orientations correctly, but had difficulty selecting the correct handshapes to represent the objects themselves. If hearing adults are indeed drawing upon their gestural resources when learning sign languages, then their difficulties may have stemmed from their having in manual gesture only a limited repertoire of handshapes to draw upon, or, alternatively, from having too broad a repertoire. If the first hypothesis is correct, the challenge for learners is to extend their handshape repertoire, but if the second is correct, the challenge is instead to narrow down to the handshapes appropriate for that particular sign language. 30 sign-naïve hearing adults were tested on Marshall and Morgan's task. All used some handshapes that were different from those used by native BSL signers and learners, and the set of handshapes used by the group as a whole was larger than that employed by native signers and learners. Our findings suggest that a key challenge when learning to express locative relations might be reducing from a very large set of gestural resources, rather than supplementing a restricted one, in order to converge on the conventionalized classifier system that forms part of the grammar of the language being learned.

Dataset Information

Does gesture strengthen sensorimotor knowledge of objects? The case of the size-weight illusion.

Publications

Does gesture strengthen sensorimotor knowledge of objects? The case of the size-weight illusion.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets