The identification of materials from patterns of fluid flow

The physical interactions among objects in the natural environment can cause dramatic changes in their shapes or patterns of motion, and those changes can provide reliable information to distinguish different types of events or materials. The present research was designed to investigate the identification of fluid materials. Observers viewed computer animations and static images of a shiny orange translucent fluid flowing from a tube into a glass jar, and they were asked to make confidence ratings about whether the depicted material looked like water/juice, oil/paint, honey/molasses, or caulk/toothpaste. The results reveal that observers can identify different types of fluid materials within broad overlapping categories based on qualitative characteristics of fluid flow that only occur within limited ranges of viscosity.