All observation involves both perception and cognition. Sensory neurophysiology investigates the relation between the processes of perception and stimulation. Schizophrenics are more likely to rely on auditory cues than visual cues in speech perception. Aristotle focused on cognitive areas pertaining to memory, perception, and mental imagery. This causes loss of depth perception and binocular vision. Anesthesiology focuses on perception of pain, and pharmacologic alteration of consciousness. There is a relationship between areas of the brain associated with perception and mental rotation. Human senses are limited and subject to errors in perception, such as optical illusions. His early work focused on visual perception and attention. Illusions can occur with the other senses including those involved in food perception. Relativism is the idea that views are relative to differences in perception and consideration. Vasopressin has shown nootropic effects on pain perception and cognitive function. Dizziness is an impairment in spatial perception and stability. The extravert is focused on the outside world of objects, sensory perception and action. Piaget studied areas of intelligence like perception and memory that are not entirely logical.