Abstract
Our tactual perceptual experiences occur when we interact, actively and passively, with environmental objects and surfaces. Previous research has demonstrated that active manual exploration often enhances the tactual perception of object shape. Nevertheless, the factors that contribute to this enhancement are not well understood. The present study evaluated the ability of 28 younger (mean age was 23.1 years) and older adults (mean age was 71.4 years) to discriminate curved surfaces by actively feeling objects with a single index finger and by passively feeling objects that moved relative to a restrained finger. While dynamic cutaneous stimulation was therefore present in both conditions, active exploratory movements only occurred in one. The results indicated that there was a significant and large effect of age, such that the older participants’ thresholds were 43.8 percent higher than those of the younger participants. Despite the overall adverse effect of age, the pattern of results across the active and passive touch conditions was identical. For both age groups, the curvature discrimination thresholds obtained for passive touch were significantly lower than those that occurred during active touch. Curvature discrimination performance was therefore best in the current study when dynamic cutaneous stimulation occurred in the absence of active movement.
Highlights
In past research with objects that vary in 2-D shape[1,2,3], active touch frequently produced higher identification or shape matching performance than static touch
Significant kinesthetic input/efference copy only occurred during active touch
According to a 2 × 2 factorial analysis of variance (ANOVA, age × touch type), the discrimination thresholds obtained for passive touch were significantly smaller than those obtained for active touch (F(1, 26) = 27.49, p < 0.001, η 2p = 0.51)
Summary
In past research with objects that vary in 2-D shape[1,2,3], active touch frequently produced higher identification or shape matching performance than static touch. In Experiment 3 of Norman et al.[4], solid shape discrimination performance obtained with active haptic manipulation was compared to that obtained when the participants’ manual exploration was restricted. Curvature discrimination is often better (e.g., lower thresholds) for active touch as compared to static or passive touch[6,7,8] At the moment, it is not entirely clear exactly what information contributes to the superiority of performance that is frequently obtained during active haptic exploration. It is interesting to note that older adults frequently perform as well as younger adults for curvature or shape-related tasks where dynamic touch, or active haptic exploration, is allowed[7,9,12,13,14]. 0.2/m fingers and hand)? Does the good performance depend upon kinesthesis and/or efference copy and require actual hand/arm movement? The purpose of the current experiment was to answer such questions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
