Visual PerceptionChapter 3

Sensation & PerceptionSensation: Occurs when our sensors (internal & external) detect & respond to information.

Perception: assigning meaning to the information that we sense. This occurs in the brain and is a personal interpretation.

When you view the next 3 images, your eyes will gather information, then you brain will select certain parts of that information, organise the parts and finally interpret and evaluate them.

Role of the eye in Visual Perception

View clip on the eye

Reception, Transduction, Transmission

Reception: photoreceptors (rods & cones) in the retina detect light stimulus

Transduction: Light energy (EM) is converted into electrochemical energy

Transmission: Electrical message is sent to the visual cortex in the brain via the optic nerve.

AT 2: From Light To Lobe

Movie clip: Sensation & perception

Perception: Gestalt principles

Gestalt – the way we organise parts into a wholeWe mentally ‘fill in’ the parts that we can’t see.

1. figure-ground organisation Object is the figure, everything else is backgroundNeeds a line or boundary (contour)Contour is part of the object

2. Closuretendency to mentally fill in or

ignore gaps in the object

3. SimilarityTendency to group similar

features together

Perception: Gestalt principles

4. Proximity tendency to perceive parts that are close

together as belonging together.

Perception:Depth principles

Perception:Depth principles

Ability to accurately estimate the distance of an object (can see 3-D)

1. Binocular (requires both eyes) Convergence Retinal disparity

Perception:Depth principles

Ability to accurately estimate the distance of an object (can see 3-D)

2. Monocular (requires only one eye)AccommodationPictorial Cues

linear perspective interposition texture gradient relative size height in the visual field

Perception:Perceptual constancies

3. Perceptual Constanciesshape constancysize constancy brightness constancy

Explorationshttp://faculty.washington.edu/chudler/chvision.htmlhttp

://academics.tjhsst.edu/psych/oldPsych/perception/

Folio Activity: Stroop Effecthttp://faculty.washington.edu/chudler/words.html

Perceptual Set