"Definitely a toaster": Identifying container contents by touch and sound

Can you tell what's inside a sealed container just by touching it? Prior work in "container haptics" has focused on numbers-how many marbles are rolling around, or how full a bottle is. Here, we explore whether humans can make qualitative judgments-what kind of thing is inside-without seeing it. Across three studies, participants explored containers filled with dry food items (e.g., flour or granola) using touch, with or without sound. Surprisingly, even with no visual (or auditory cues), participants could often identify, or at least describe, the contents based on texture, size, and density. These findings suggest that your hands are better at guessing container contents than you might think.