Perception and reality
In the case of visual perception, some people can actually see the percept shift in their mind's eye.[13] Others, who are not picture thinkers, may not necessarily perceive the 'shape-shifting' as their world changes. The 'esemplastic' nature has been shown by experiment: an ambiguous image has multiple interpretations on the perceptual level.
This confusing ambiguity of perception is exploited in human technologies such as camouflage, and also in biological mimicry, for example by European Peacock butterflies, whose wings bear eye markings that birds respond to as though they were the eyes of a dangerous predator.
There is also evidence that the brain in some ways operates on a slight "delay", to allow nerve impulses from distant parts of the body to be integrated into simultaneous signals.
Perception is one of the oldest fields in psychology. The oldest quantitative laws in psychology are Weber's law-which states that the smallest noticeable difference in stimulus intensity is proportional to the intensity of the reference-and Fechner's law which quantifies the relationship between the intensity of the physical stimulus and its perceptual counterpart (for example, testing how much darker a computer screen can get before the viewer actually notices). The study of perception gave rise to the Gestalt school of psychology, with its emphasis on holistic approach.