136 Top-Down Lighting Bias

A tendency to interpret objects as being lit from a single light source from above.

• People interpret dark areas of objects as shadows resulting from a light source above the object.

• Things that are lit from the top tend to look natural; whereas things that are lit from the bottom tend to look unnatural.

• Objects that are lighter at the top and darker at the bottom are interpreted to be convex, and objects that are darker at the top and lighter at the bottom are interpreted to be concave.

• Use a single top-left light source to depict natural-looking things. Explore bottom-up lighting when depicting unnatural-looking or foreboding things. Adjust the difference between light and dark areas to vary the perception of depth.

See Also 3D Projection • Figure-Ground Relationship Threat Detection • Uncanny Valley

The Lincoln Memorial is usually lit top-down (left), but it has on occasion been lit bottom-up (right), revealing zombie Lincoln.