Any of the relatively independent sensory systems such as vision, hearing, smell, taste, and touch, the traditional five senses originally identified in about 350 bc by the Greek philosopher Aristotle (384–322bc), who recognized that touch includes different senses within itself. In 1904 the Austrian physiologist Max von Frey (1852–1932) identified the four component sensations of touch as heat, cold, pain, and pressure, pressure now being known to include sensations of texture and vibration. The sensory systems associated with the vestibular system, kinaesthesis, proprioception, and the magnetic sense are also sometimes regarded as sensory modalities. Also called a modality or a sense or a communication channel. See also cross-modal matching, cross-modal transfer, egocentre, modality effect, Molyneux's question, synaesthesia (1).