טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentHilsenrat Marcos
SubjectThe Effect of Unaware Haptic Perception on Changes in
Manual Responses and Cognition Behavior
DepartmentDepartment of Education in Science and Technology
Supervisor Professor Miriam Reiner
Full Thesis textFull thesis text - English Version


Abstract

Through sensory interaction with the environment, humans build mental models, which then become a basis for learning and extension to new contexts. One of the central sensory channels is touch. The sense of touch provides information about objects, and is a central component in learning. In this research we present four studies concerning human haptic interaction with object surface. In the first study we investigated the effects of unaware haptic stimuli on users’ motor interaction with virtual objects. We run a texture-difference recognition test in which subjects glided a pen-like stylus along a virtual surface with varying roughness. We found that subjects were not aware of changes in texture roughness below a threshold limit, yet the force they applied changed. These results suggest that performance can be affected through subliminal cues. In the second study we tested whether people that touch two virtual surfaces, which differ by imperceptible differences in roughness or compliance, tend to prefer rougher or smoother, softer or stiffer surfaces, in accordance with their natural tendency. In forced choice preference and recognition tests between surfaces with differences in stimuli below the level of awareness, participants preferred the surface in accordance with their natural tendency. Recognition was at chance level. These results show that subliminal perception of roughness and compliance strength, affects texture preferences. In the third study we made a comparative research between the discrimination capabilities of professionals in manual skills and non-professionals, in a task that was not related to their field of expertise. In a texture-difference recognition test subjects glided on virtual surfaces with different roughness. Using a binary search paradigm, roughness differences were changed until the desired degree of accuracy was achieved. We found that laymen were significantly more sensitive than experts on roughness discrimination in tasks that were not within the range experience of the experts, suggesting that expertise may be centered around specific contexts, and is not transferred to other situations. In the fourth study we examined whether the metaphorical association of colors that were mentioned in the literature as linguistic metaphors of “hardness”/”softness” content have a different impact on motor responses in accordance with their metaphorical significance. We found that participants differed significantly in the applied forces on the surfaces with different metaphorical significance, and did not differ significantly when the surfaces were with similar metaphorical significance. These results suggest that aware stimuli induced unaware motor actions.