Abstract Everyday experience suggests that handheld containers convey auditory and haptic information about their contents. The primary objective of this study was to examine how these two sources of information interact. Across three experiments, participants estimated the number of beads in cardboard boxes under three sensory conditions: haptics-only, auditory-only, and auditory-haptic. We hypothesized that the auditory-haptic condition would yield more accurate and precise estimates. A secondary objective was to assess the effects of time and manipulation constraints. In Experiment 1, participants were limited to 5 s of exploration using a standardized movement; Experiment 2 removed the time constraint, and Experiment 3 additionally removed the movement constraint. Results indicated that participants could reliably estimate the number of items under all conditions but provided little evidence for multisensory integration. When both constraints were removed, the haptic-only condition produced significantly more accurate estimates. These findings suggest that manipulation constraints influence enumeration performance and that haptic cues can support accurate judgments when exploration is unconstrained.
Frissen et al. (Fri,) studied this question.