Perceiving multiple properties of a single person-probe-surface system.

We performed three experiments to investigate the extent to which people can selectively perceive different properties of a person-probe-surface system, and the extent to which such abilities are supported by sensitivities to different (components of) invariant mechanical parameters. Participants probed a surface with a wielded object and attempted to perceive an exteroceptive property of the probe (whole length), an exproprioceptive property of the probe (partial length), and an exteroceptive property of the surface (distance). After controlling for potential confounds, we found that participants were able to selectively perceive each of these properties, and that in each case, such abilities were supported by sensitivity to distinct components of mechanical invariants. The results suggest that people can selectively attend to properties both across and within components of a person-probe-surface system and are discussed in the context of the invariant mechanical parameters that support this ability.