The ability to predict accurately the mechanical properties of the objects we interact with is essential for skilled and dexterous manipulation. For example, when lifting an object, people typically scale the vertical lifting force to predicted object weight and, if the prediction is accurate, this enables them to lift smoothly. However, weight predictions are not used simply in action; they also influence our perception of weight. Strong evidence suggests that weight judgments are biased by expected weight, such that an object will be judged relatively heavy or light if it is heavier or lighter than expected, respectively. This bias is important, because it enables people to make comparative weight judgments and communicate this information to others. This chapter discusses how information about object mechanical properties, including weight, is represented in the brain, and the relation between representations of objects employed by the action system and representations of the same objects used by the perceptual system to make judgments about object properties.
Keywords: manipulation; vertical lifting; perception of weight; object properties
Chapter. 9089 words. Illustrated.
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