Perception Theory

In order to receive information from the environment we are equipped with sense organs example eye, ear, and nose. Each sense organ is part of a sensory system which receives sensory inputs and transmits sensory information to the brain.

Hearing is the ability to perceive sound by vibrations through the ear. The inability to hear is known as deafness. Hearing involves the computationally complex task of separating the sources of interest (Moore 2009). Sound does not usually come from a single source, it may come from multiple sources and directions are superimposed as they arrive at the ears.

Taste is another of the five senses. It is the ability to detect flavour of substances including but not limited to food. The sensation can be categorised into five tastes: sweetness, bitterness, sourness, saltiness and umami. Humans receive tastes through sensory organs called taste buds (Daniel 2005).

Olfaction is the sense of smell and this sense is mediated by sensory cells of the nasal cavity. The inability to smell is known as anosmia.

Touch is a perception resulting from activation of the skin including hair follicles and also the tongue, throat and mucosa. The loss of impairment of the ability to feel is called tactile anaesthesia while paresthesia is a sensation of tingling, prinking or numbness of the skin.

Visual perception is the ability to interpret information and surroundings from the effects of light reaching the eyes, the result of this is known as eyesight or vision. The loss of vision is known as blindness. There are two schools of thought about how vision is carried into the body. The first "emission theory" postulates that vision occurs when rays emanate from the eyes and are intercepted by visual objects. The second school advocates the "intro-mission" approach which sees vision as coming from something entering the eyes which represent an object (Finger 1994).

Gestalt theory of visual perception:-
 

Gestalt means when parts identified individually have different characteristics to the whole (Gestalt means "organised whole") for example describing a tree, its parts are trunk, branches, leaves, perhaps blossoms or fruit. But when you look at an entire tree, you are not conscious of the parts, you are aware of the overall object, the tree. Parts are of secondary importance even though they can be clearly seen. There are six principles associated with the Gestalt theory which are: - proximity, similarity, common fate, good continuation, closure and finally area and symmetry.

A major theoretical issue on which psychologists are divided is the extent to which perception relies directly on the information present in the stimulus. Some argue that perceptual processes are not direct, but depend on the perceiver's expectations and previous knowledge as well as the information available in the stimulus itself.

This controversy is discussed by 2 theorists:-

Gregory (1970) who argues that perception is a constructive process which relies on top-down processing and Gibson (1966). He argued against the idea that perception involves top-down processing. Gibson criticises Gregory's suggestion of visual illusions as artificial examples and not images found in the normal environments. Instead Gibson argues that perception is direct and not subject to hypothesis testing as suggested by Gregory. He further postulates that there is enough information in our environment to make sense of the world in a direct way, "sensation is perception: what you see is what is what you get".


Further reading:
http://www.users.totalise.co.uk/~kbroom/Lectures/gestalt.htm

http://www.lumosity.com/landing_pages/42
http://www.simplypsychology.org/perception-theories.html