Pseudo-slimy: A novel phenomenon to evoke stickiness perception

Everyday materials such as honey, shampoo, and oil are often described not only in terms of their viscosity but also by the sense of stickiness they evoke during contact and separation. Although previous studies have identified visual cues that support the perception of viscosity, the visual basis of stickiness perception, particularly in interactive contexts, remains poorly understood. Here, we introduce a novel phenomenon, termed pseudo-slimy, in which participants experience a sense of stickiness toward a visually deforming object that stretches and eventually breaks in response to their own finger movements. In Experiments 1 and 2, we systematically manipulated the distance at which the object visually broke (break distance) and found that larger break distances elicited significantly stronger impressions of stickiness. In Experiment 3, we demonstrated that the perceived strength of this phenomenon could be quantitatively mapped onto a psychological stickiness scale derived from common viscoelastic materials, showing a significant correlation between adjusted break distances and scale values. Together, these results suggest that the spatial extent of visually induced resistance to separation serves as a powerful cue for stickiness perception. The present findings provide new insights into how humans visually infer material stickiness in interactive situations and offer a potential framework for pseudo-haptic applications that evoke tactile qualities through visual feedback alone.