Influence of visually perceived shape and brightness on perceived size, expected weight, and perceived weight of 3D objects

Abstract

In the size–weight illusion, when two objects of identical weight but different volume are lifted, the smaller object is typically perceived to weigh more than the larger object. A well-known explanation for this and other weight illusions is provided by the hypothesis that perceived weight results from the contrast between actual and expected weight. More recently, it has been suggested that an object’s size may exert a direct and automatic effect on its perceived weight, independently of expected weight. Here we test these two hypotheses by exploring two illusions that have been known for a long time but have remained relatively underexplored, namely the shape–weight and brightness–weight illusions. Specifically, we measured the influence of visually perceived shape and brightness on the perceived size, the expected weight, and the perceived weight of 3D plastic objects. A numerical rating task was used in Experiment 1, and a paired comparison task was used in Experiment 2. The results showed that spheres were perceived to be heavier than tetrahedrons and cubes, and cubes were perceived to be heavier than tetrahedrons. We did not find any consistent relationship between brightness and perceived weight. A systematic comparison between perceived size, expected weight, and perceived weight showed that the visual shape–weight and brightness–weight illusions are partially inconsistent with the hypothesis that perceived weight results from the contrast between actual and expected weight and with the hypothesis that perceived weight results from the contrast between actual weight and perceived size. The results appear to suggest that there may be a dissociation between the processing of variables that contribute to the conscious experience of size, such as brightness and vertical height, and the processing of variables that contribute to perceived weight, such as surface area.

A Systematic Review of Weight Perception in Virtual Reality: Techniques, Challenges, and Road Ahead

“…The tetrahedron was perceived as being significantly lighter than the cube. The phenomenon is supported by Vicovaro et al [56] in their recent study. The experiments revealed a significant effect of shape on weight perception, although the direction and the magnitude of the biases were subject dependent.…”

“…The study concluded that the existence of the brightness-weight illusion was restricted to a specific weight range and a specific mode of lifting. Therefore, the brightness-weight illusion is less robust and generalizable than the size-weight, material-weight, and shape-weight illusions [56].…”

“…Further research supported this hypothesis proposed the association between surface lightness and weight and termed it as brightness-weight illusion [26]. However, the results from Vicovaro et al [56] are inconsistent with the findings, demonstrated a lower 0.49 probability compared to 0.8 probability (in [26]) for a white object to be judged as heavier than a black object. It was argued that the discrepancy might be due to the differences in test objects' weight (220g versus 129g) and the mode of lifting (using a string versus holding in the hand) during the experiments, which reduced the subjects' sensitivity to subtle differences in weight.…”

“…The weight perception also affected by the object properties, such as object size [21], [40]- [43], the material [28], [44]- [47], distribution of mass [48]- [50], shape [51], [52], temperature [13], [53], [54], and color or brightness [26], [55], [56]. Cognitive factors such as conceptual expectancy [57], [58] and social cues [59] are another important factors that cannot be excluded in weight perception study.…”

Soft like velvet and shiny like satin: Perceptual material signatures of fabrics depicted in 17th century paintings

“…If participants were able to retrieve the material identity, heaviness could have been inferred through an “associative approach” ( Schmidt et al, 2017 ). One possible association could have been that darker objects are perceived to be heavier than brighter ones ( Walker, Scallon, & Francis, 2017 ; Vicovaro, Ruta, & Vidotto, 2019 ). From additional analysis, we found that ratings of heaviness in the crop condition were indeed highly negatively correlated with the mean luminance of the stimuli ( r = −0.73, p < 0.001).…”