object and scene perception

why perception hard?

stimulis on the retina is ambiguous

objects can be partially occluded or blurred

objects look different in different poses from diff viewpoints

structuralism

distinguish between sensations and perceptions

• sensations: elementary processes occur in response to stimulation

• perception: conscious awareness of objects and scenes

claims sensations combine to form perceptions - conscious awareness is sum of elementary sensations - nothing that isnt already present

gestaltism

conscious awareness is moe than sum of elementary sensations

two pieces of evidence

• apparent motion - two dots in quick succession = perceived movement

• illusory contours - contours seen in locations with no phyiscal contours

gestalt principles of grouping

• people perceive objects and scenes due to perceptual organisations

• can perceptually organise scene into constituent objects

grouping

parts of an image are perceptually bound to form a perceptual whole

segregation

parts of scene aerceptually separated to form separate wholes

7 key principles of grouping

1. good continuation - aligned contours grouped form single object

2. pragnaz/simplicity - grouping to make figure simple as possible

3. similarity - more similar objects more likely to be grouped

4. proximity - closer things more likely to be grouped

5. common fate - moving same way grouped together

6. common region - in same region grouped

7. uniform connectedness - connected regions + same visual

principles of segregation

figural cues - more likely to be seen if:

• in front of rest

• bottom of image

• convex/bulge

• recognisable

• experience

gist perception

when scene flashed rapidly may not be able to identify all objects but get overall perception about what scene about