Abstract
According to the action-specific theory of perception, a person's dynamic ability to act in the environment affects her/his spatial perception. Empirical evidence shows that the elderly perceive distances as farther compared with younger adults and that the harder the ground surface to walk, the farther the perceived distance. Such results suggest a general perceptual readaptation promoted by the aging process that is fine-tuned with the decline of the motor resources. However, it is still unknown whether the elderly space perception is affected by interindividual differences in their functional autonomy (FA) and whether the decline of motor resources affects spatial categorization only when distances are judged with reference to the observer's own body or also when they are judged with reference to the body of another agent present in the scene. To this aim, a sample of elderly adults with preserved cognitive functions but different levels of FA, measured through the Instrumental Activity of Daily Living (IADL) scale, were enrolled and tested on the extrapersonal space categorization task. This task requires judging the position of a target as “Near” or “Far” with respect to different reference frames (RFs): centered on the observer's body (Self RF) or centered on external elements, like another body (Other RF) or an object (Object RF). Results indicated that the higher the level of FA, the wider the space categorized as “Near” when adopting as reference frame our own body or the body of another agent in the scene, but not a static object. In conclusion, the individual functional autonomy of elderly individuals, which is strongly influenced by motor resources and efficiency, modulates how the surrounding space is represented, but only when the distance judgment implies an agent body, thus providing new relevant data for recent embodied cognition models of aging.
Highlights
According to the action-specific theory of perception [1], a person’s dynamic ability to act in the environment, which is largely determined by her/his body, affects her/his spatial perception. ese effects are suggested to be potentially adaptive for planning future actions based on the perceiver’s abilities rather than on behaviorally irrelevant metrics [1].Within the extrapersonal space, pioneering research by [3], for example, demonstrated that hills are judged as steeper when people are fatigued or carry a heavy backpack
Still neglected, is the level of functional autonomy in daily life, which is strongly associated with physical performance [15] and is crucial when considering the interaction between an individual and her/his surrounding environment
The correlation with the Object reference frames (RFs) was not significant and neither the Self Judgment Transition reshold (JTT) nor the Other JTT showed a significant correlation with age and MMSE corrected score
Summary
According to the action-specific theory of perception [1], a person’s dynamic ability to act in the environment, which is largely determined by her/his body (size, control and coordination, and energetic potential), affects her/his spatial perception. ese effects are suggested to be potentially adaptive for planning future actions based on the perceiver’s abilities rather than on behaviorally irrelevant metrics [1]. The great majority of studies focused on older adults as a group, largely neglecting interindividual differences in relevant embodiment factors [13] One of these factors, still neglected, is the level of functional autonomy in daily life, which is strongly associated with physical performance [15] and is crucial when considering the interaction between an individual and her/his surrounding environment. At equal age and preserved general cognitive level, there are older people maintaining their autonomy by continuing, for example, to go out for purchases, while physical and/or familial conditions force some others to a very early assistance for daily activities In the latter case, life in assisted living facilities is frequent, where transfers and interactions with the surrounding space are strongly limited. Participants with higher autonomy levels were expected to categorize as “Near” a higher portion of space only when using a Self or Other RF (versus Object RF)
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