Year 11 Psychology Visual Perception

Sensation

The detection of light energy produced by stimulation of the visual receptors in the eye.This is a biological process that is the same (for healthy people).

Reception

First stage in the sensory process. Sensory information from the environment is received and processed by our sensory organs.

Perception

Organising, interpreting and giving meaning to what the sense organs initially process. This is an individual process due to different history/ interpretations, languages, culture.

Transduction

Process by which electromagnetic energy (light) received from the environment is converted into electrochemical energy (nerve impulse).

Transmission

Transfer of neural info from the eye to the brain via optic nerve

Selection

The detection and coding of particular features of a stimulus such as size, colour and movement. Process of sorting out or selecting the important messages from the senses and discarding any excess information. Done by feature detector cells in brain

Photoreceptors

Light-sensitive receptor cells in the retina. A cone or rod cell in the retina of the eye that responds to light by converting light energy (electromagnetic energy) into nerve impulses (electrochemical energy) so they can be transmitted to the brain.

Lens

Transparent flexible structure in the eye that focuses light on the retina by changing shape.

Receptors

Body cells that are specialised to detect and respond to sensory information

Visual illusions

Discrepancies that sometimes occur between objects in the real world and how we perceive these objects. It is a misinterpretation (error or distortion) of real visual sensory stimuli.

Rods

125 million in each retina are specialised photo-receptors for night vision and peripheral vision. Do not provide clear detail in the object. Mostly outside the fovea.

Optic nerve

This is the nerve that is involved in transmission of the electrochemical signals from the photoreceptors in the retina to the visual cortex in the occipital lobe of the brain.

Retina

Layers of specialised neurons that line the rear inner surface of the eye. It receives and absorbs light, processes images and transmits neural messages to the visual cortex of the brain. Contains photoreceptors -rods and cones.

Blind spot

There are no rods or cones at this part of the retina so it doesn't receive any information from this part of the visual field. It is where the Optic nerve leaves the retina.

Cones

Important for daylight vision, detection of fine detail (acuity) and colour vision.

Don't operate well in dim light.

Most numerous in the fovea

6.5 million cones

Perceptual set

Perceptual set is the predisposition, or 'readiness', to perceive something in accordance with what we expect it to be

Due to prior experience, motives, mood and context. Can help us to interpret it more quickly.

Photoreceptors

Light-sensitive receptor cells in the retina. A cone or rod cell in the retina of the eye that responds to light by converting light energy into nerve impulses so they can be transmitted to the brain.

pupil

the adjustable opening in the center of the eye through which light enters

Cornea

The clear tissue that covers the front of the eye. It helps to focus light onto the lens

ciliary muscle

muscle that helps focus light on the retina by controlling the curvature of the lens of the eye