People respond to the world they see, not the world that is really there. The outside observer does not know how people interpret the world, so cannot understand or predict their behaviour. The trait theorist fails to find consistency of behaviour, because the theorist's way of seeing things and judging consistency is not the person's way of seeing things; people are consistent by their standards, but not by the psychologist's. The learning theorist's extrapolation from Thorndike's cats or Pavlov's dogs to humans fails, because people respond to the stimulus they see, not the one the psychologist has provided. Perceptual, and phenomenological, accounts of personality argue that understanding how people see and interpret the world and the people in it gives the key to understanding personality.

Perceptual approaches vary in the extent of their ambition. Some simply try to include perceptual factors in a more general model. Thus Mischel's cognitive social learning theory takes account of how people see the world, and how they value what they see. At this level, any adequate theory of human personality should include perceptual factors, as, indeed, Allport's trait theory does. Other perceptual approaches go far beyond this, and assert that how people perceive things is the sum total of personality, or even of all psychology. The Oxford English Dictionary defines as phenomenalism ‘the metaphysical dogma that phenomena are the only objects of knowledge or the only realities’.