Perception of slant-in-depth is automatic.

Two experiments assessed perception of the slant-in-depth of static irregularly contoured shapes when attention was withdrawn from processing slant-in-depth. The experiments showed that when the memory load of the experimental task is minimal, discrimination of slant-in-depth is evidenced even when attention has not been directed to slant discrimination. The findings are brought to bear on a model of perceiving shape-at-a-slant (Epstein & Lovitts, 1985) that partitions the components of the process into automatic and attention-demanding operations.