Attention is the gatekeeper that selects which sensory information gets passed into short-term memory, filtering out the noise around you. Your brain actively organizes whatever makes it through, and that constructive process sometimes goes wrong, producing illusions. By studying visual illusions, psychologists can see how your knowledge, expectations, and biological limits shape your private view of reality.
Entrance exams frequently test the difference between illusions (misreading a real stimulus) and hallucinations (perceiving something that is not there at all). Memorize the classic examples like the Müller-Lyer and Ponzo illusions, and remember they show how the brain leans on background context and learned depth cues to judge size. You should also expect questions on selective attention acting as the gatekeeper between sensory memory and short-term memory.
Part of Basic Psychology, module “Sensation & Perception”. Sign in (free) to read the full notes, flashcards and the lesson quiz.