I am as fooled as you are, say some primates … but only sometimes.

The evidence of "cognitive impenetrability" is a byproduct of the fact that minds often must react quickly to sensory stimulation, and they must attempt to make visual stimuli meaningful given what the perceiver knows of the world. Hanus et al. remind us that such immediate decisions may, in fact, help keep us alive, but at the possible cost of sometimes misaligning visual perception and physical reality. That said, not all people fall prey to all illusions, and many individuals may only fall prey to some illusions, but not others. A big question is why this happens. (PsycInfo Database Record (c) 2023 APA, all rights reserved).