Gregory's illusions

Gregory's illusions demonstrate how our brain interprets sensory information, sometimes leading us to see things that aren't true. They reveal that perception isn't just about what we see—it's shaped by our past experiences, expectations, and mental processes. For example, illusions like the Müller-Lyer or the Ponzo trick show how context and perspective can distort size and depth perception. Gregory suggested that these illusions expose the constructive nature of perception, meaning our brains actively interpret sensory input, filling in gaps and making guesses based on prior knowledge, which can result in illusions or misperceptions.