Halfway volumes based on different geometrical properties.

Relationships between volumes (), surface areas (), radii (), diameters () and edge lengths () of spheres and tetrahedra. The following formulas hold for the sphere: , and , and for the tetrahedron: and . Adaptation volumes are always and and thus the correct halfway volume is 8 cm. The values in bold are the averages of the corresponding values of the two reference stimuli. The rightmost column gives the resulting halfway volumes if participants based their judgements on the indicated geometric property.