Perception, A visual system

Psychologists typically make a distinction between sensation and perception. Sensations are uninterpreted sensory impressions created by the detection of environmental stimuli, whereas perception refers to the set of processes whereby we make sense of these sensations. Perception enables us to literally navigate through the world, avoiding danger, making decisions, and preparing for action. Visual perception has received the most attention from researchers, and then speech.

Perception is the organization, identification, and interpretation of sensory information in order to represent and understand the environment. The perceptual process allows us to experience the world around us. Take a moment to think of all the things you perceive on a daily basis. At any given moment, you might see familiar objects in your environment, feel the touch of objects and people against your skin, smell the aroma of a home-cooked meal and hear the sound of music playing in your next door neighbor's apartment. All of these things help make up our conscious experience and allow us to interact with the people and objects around us.
Visual perception

The problem of visual perception

At the back of the eye is an area called the retina, consisting of light-sensitive neurons. However, the retina is not light sensitive at the point where the optic nerve leaves the eye and this results in a blind spot in our visual field. However, most of the time we are unaware of the existence of the blind spots associated with each eye, except where a special procedure helps draw it to our attention (see here, for example). It seems that our brains perform a "best guess" operation and try to use context to fill in the gap.

Light from an object is inverted as it falls on the retina. The same pattern of light could be caused by an infinite number of different objects, yet our brains usually manage to make the correct interpretation. This is known as the inverse projection problem. How do we make sense of visual sensations? How do we distinguish one object from another? How do we perceive depth from the array of light stimuli that strike our retinas. The transformative nature of perceptual processes is also suggested by the existence of perceptual illusions.

Perception is our sensory experience of the world around us and involves both the recognition of environmental stimuli and actions in response to these stimuli. Through the perceptual process, we gain information about properties and elements of the environment that are critical to our survival. Perception not only creates our experience of the world around us; it allows us to act within our environment.


Perception includes the five senses; touch, sight, taste smell and taste. It also includes what is known as proprioception, a set of senses involving the ability to detect changes in body positions and movements. It also involves the cognitive processes required to process information, such as recognizing the face of a friend or detecting a familiar scent.