15:00 - 16:30
Tue-P3-Poster II-2
Tue-Poster II-2
Room: P3
The Effect of Movement Direction on Spatial Frequency Discrimination In Oriented Textures
Tue-P3-Poster II-204
Presented by: Didem Katircilar
Didem Katircilar, Knut Drewing
Justus Liebig University Giessen
Haptic perception is inherently active. Variation of exploratory movement can be utilized in active touch and in turn influences perception. For example, people perceive small shapes more precisely when the finger explores them laterally as compared to anterioposterior, and they tend to adjust the exploratory direction in that task to increase perceptual performance (Drewing, 2012). Here, we investigated how movement direction of the finger affects texture perception and associated movement control. Texture perception is based on spatial cues from static touch and temporal cues from active movement. We used stimuli that maximized the relevancy of movement-related temporal cues: Oriented ridge-groove textures that have high spatial periods > 1 cm and ridge sizes of 0.5 mm, and for that static touch does not provide much information. Also, the textures were always oriented orthogonal to the finger. The finger was moving lateral or anterioposterior to the body. Participants performed a two-interval forced choice task choosing in each trial the stimulus with higher spatial frequency. We used the method of constant stimuli (one standard stimulus, 9 comparisons, step size 1 mm). Participants applied higher force during the exploration process in anteroposterior orientation than in lateral orientation while there was no difference regarding exploration velocity or texture discrimination (JNDs). We speculate that participants modify their forces to increase information gathering in a more difficult anterioposterior condition (cf. Drewing, 2012) and thus optimize the exploration process for texture discrimination.
Keywords: haptic perception, texture perception, spatial frequency discrimination, haptic exploration, finger movement direction