Perceiving intersensory and emotional qualities of everyday objects: a study on smoothness or sharpness features with line drawings by designers

A large number of studies have focused on the aesthetic value of smoothly curved objects. By contrast, angular shapes tend to be associated with tertiary qualities such as threat, hardness, loudness, nervousness, etc. The present study focuses on the effect of curvilinearity vs angularity on the aesthetic experience of design artefacts. We used the drawings of everyday objects with novel shapes created by 56 designers (IUAV image dataset). Each drawing had two versions: a smooth and an angular version. To test new tertiary associations, beyond aesthetic value, we obtained ratings for seven characteristics (‘soft/hard, sad/cheerful, male/female, bad/good, aggressive/peaceful, agitated/serene, useless/useful’) from 174 naïve observers. Importantly, each naïve rater saw only one of the two versions of an object. The results confirmed a significant relation between smoothness and hardness as well as other (tertiary) associations. The link between smoothness and usefulness confirms that perceptual utility is significantly influenced by the shape of the object. This finding suggests that tertiary qualities convey both static and functional information about design objects. The role of perceptual constraints in drawing design artefacts is also discussed.