Gradience

Categorical perception is the experience of percept invariances in sensory phenomena that can be varied along a continuum. Multiple views of a face, for example, are mapped onto a common identity, visually distinct objects such as cars are mapped into the same category and distinct speech tokens are identified as belonging to the same phonetic distinct and separate percept. Within a particular part of the continuum, the percepts are perceived as the same, with a sharp change of perception at the position of the continuum where there is identity change. Categorical perception is opposed to continuous perception, the perception of different sensory phenomena as being located on a smooth continuum.