A Very Short Introduction
2. Perceptual theories—direct, indirect, and computational
indirect or constructivist theories of perception and they share the idea that we need to construct or reconstruct our perceptions from limited sensory information. This view of perception sounds very plausible because we, as humans, are able to make cognitive inferences and hypotheses that go beyond the available evidence. Moreover, if our perceptions are only guesses or inferences about the external world, we should expect that we will sometimes perceive the world incorrectly and suffer from illusions, and this seems to be the case.
Gillian Butler and McManus Freda
2. What gets into our minds? Perception
7. Delusions about illusions
). In the Ebbinghaus illusion ( ), the circle on the right (surrounded by the smaller circles) appears to be larger than the same-sized circle on the left that is surrounded by larger circles. In both illusions, the size we perceive does not correspond to the real size, as can be verified by using a ruler or tape measure.