1215592
doi
10.5281/zenodo.1215592
oai:zenodo.org:1215592
Metzger, Anna
Justus-Liebig University Giessen
Drewing, Knut
Justus-Liebig University Giessen
Active Haptic Exploration of Softness: Indentation Force Is Systematically Related to Prediction, Sensation and Motivation
Lezkan, Alexandra
Justus-Liebig University Giessen
info:eu-repo/semantics/openAccess
Creative Commons Attribution 4.0 International
https://creativecommons.org/licenses/by/4.0/legalcode
Haptic Perception; Softness; Exploratory Movements; Movement Control; Action and Perception
<p>Active finger movements play a crucial role in natural haptic perception. For the perception of different haptic properties people use different well-chosen movement schemes (Lederman & Klatzky, 1987). The haptic property of softness is stereotypically judged by repeatedly pressing one’s finger against an objects’ surface, actively indenting the object. It has been shown that people adjust the peak indentation forces of their pressing movements to the expected stimulus’ softness in order to improve perception (Kaim & Drewing, 2011). Here, we aim to clarify the mechanisms underlying such adjustments. We disentangle how people modulate executed peak indentation forces depending on predictive versus sensory signals to softness, and investigate the influence of the participants’ motivational state on movement adjustments. In Experiment 1, participants performed a 2AFC softness discrimination task for stimulus pairs from one of four softness categories. We manipulated the predictability of the softness category. Either all stimuli of the same category were presented in a blocked fashion, which allowed predicting the softness category of the upcoming pair (predictive signals high), or stimuli from different categories were randomly intermixed, which made prediction impossible (predictive signals low). Sensory signals to softness category of the two stimuli in a pair are gathered during exploration. We contrasted the first indentation (sensory signals low) and last indentation (sensory signals high) in order to examine the effect of sensory signals. The results demonstrate that participants systematically apply lower forces when softer objects (as compared to harder objects) are indicated by predictive signals. Notably, sensory signals seemed to be not as relevant as predictive signals. However, in Experiment 2, we manipulated participant motivation by introducing rewards for good performance, and showed that the use of sensory information for movement adjustments can be fostered by high motivation. Overall, the present study demonstrates that exploratory movements are adjusted to the actual perceptual situation and that in the process of fine-tuning, closed- and open-loop mechanisms interact, with varying contributions depending on the observer’s motivation.</p>
Lezkan, A., Metzger, A., & Drewing, K. Front. Integr. Neurosci. (2018). doi: 10.3389/fnint.2018.00059
Each Zip file contains all data for one of the experiments relative to the publication. A description of the variables is contained in the file VARIABLE_CODES.txt for each experiment.
Zenodo
2018-04-09
info:eu-repo/semantics/article
1215591
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