title: Perceptual grouping by similarity of surface roughness in haptics: the influence of task difficulty.
abstract: We investigated grouping by similarity of surface roughness in the context of task difficulty. We hypothesized that grouping yields a larger benefit at higher levels of task complexity, because efficient processing is more helpful when more cognitive resources are needed to execute a task. Participants searched for a patch of a different roughness as compared to the distractors in two strips of similar or dissimilar roughness values. We reasoned that if the distractors could be grouped based on similar roughness values, exploration time would be shorter and fewer errors would occur. To manipulate task complexity, we varied task difficulty (high target saliency equalling low task difficulty), and we varied the fingers used to explore the display (two fingers of one hand being more cognitive demanding than two fingers of opposite hands). We found much better performance in the easy condition as compared to the difficult condition (in both error rates and mean search slopes). Moreover, we found a larger effect for the similarity manipulation in the difficult condition as compared to the easy condition. Within the difficult condition, we found a larger effect for the one-hand condition as compared to the two-hand condition. These results show that haptic search is accelerated by the use of grouping by similarity of surface roughness, especially when the task is relatively complex. We conclude that the effect of perceptual grouping is more prominent when more cognitive resources are needed to perform a task.
authors.affiliation: Laboratory of Experimental Psychology, University of Leuven (KU Leuven), Tiensestraat 102 (Box 3711), 3000, Leuven, Belgium.|Parenting and Special Education Research Group, University of Leuven (KU Leuven), Leopold Vanderkelenstraat 32 (Box 3765), 3000, Leuven, Belgium.
authors.forename: V
authors.initials: V
authors.lastname: Van Aarsen
authors.affiliation: Laboratory of Experimental Psychology, University of Leuven (KU Leuven), Tiensestraat 102 (Box 3711), 3000, Leuven, Belgium. Krista.Overvliet@gmail.com.|Department of Biological Psychology and Neuropsychology, University of Hamburg, Von-Melle-Park 11, 20146, Hamburg, Germany. Krista.Overvliet@gmail.com.
authors.forename: K E
authors.identifier: 0000-0002-3537-8172
authors.initials: KE
authors.lastname: Overvliet
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008465:Mechanoreceptors / Q000502:physiology*; D013647:Task Performance and Analysis; D055698:Touch Perception / Q000502:physiology*; D055815:Young Adult
keywords: Haptic search; Haptics/touch; Perceptual grouping; Roughness perception; Task difficulty