Effect of viewing angle on volume perceptions for paired tumblers

Abstract

This study examined how tumbler characteristics influenced the perception of volume at different viewing angles. Three tumbler characteristics were individually examined, namely, shape, size, and elongation. At four viewing angles (0°, 30°, 60°, and 90°), 50 participants poured a certain amount of liquid (150 or 200 mL) into a designated tumbler according to their perception. Results showed that tumbler size and elongation influenced volume perception. At viewing angles of 0° and 30°, the participants poured more liquid into short-wide tumblers than into tall-slender tumblers. At viewing angles of 60° and 90°, the results were opposite. The reason may be that the change of viewing angle made the participant’s sight cues from the container diameter more visible than those from the container height. Similar results were obtained for the pair of small and large tumblers. However, no effect of viewing angle on tumblers with different geometric shapes was observed. The contradictory results in comparison with those of previous studies may be related to viewing angle; in addition, the effect of viewing angle was also influenced by the characteristics of tumblers.