Computation of Sensory-Affective Relationships Depending on Material Categories of Pictorial Stimuli

Exposure to stimuli gives rise to sensory and affective experiences. Computing the relationships between these experiences is instrumental to designing affectively appealing products and understanding human experiences. Hierarchical structures of sensory and affective responses, which can be built through adjective rating tasks, are regarded as an effective means for expressing relationships between sensory and affective responses. Naturally, these hierarchical structures depend on the type of stimulus; however, so far, their dependencies on material categories have yet to be examined. We therefore investigated how hierarchical structures of affective and sensory responses depend on seven material categories: fabric, leather, wood, paper, foliage, stone, and glass. Each material category had 100 visual representations selected from the Flickr Material Database. Thirty-nine participants were asked to rate 368 pictures across a set of materials. The questionnaire adjectives included visually- and haptically-centered items although the stimuli were purely visual. We found that the structures differed substantially among the material categories, although there were some commonalities. Particularly, the positions of polysemic or multimodal adjectives such as “light” and “uncomfortable” in the hierarchy were highly dependent on the material category. For example, “light” has both physical (lightweight) and psychological (e.g., non-solemn, cheerful) meanings. For stone and glass (generally considered to be of heavy weight), the psychological meanings were primarily considered. Conversely, the physical meanings were predominant for fabric, leather, wood, paper, and foliage, for which weight is a factor in judging quality. The present study helps interpret affective descriptors whose meanings vary among types of stimuli.