Perception

PSY Chapter 4

Attention/Selection

Determines what you will attend to/perceive
Focusing on SOME stimuli and IGNORING other stimuli
Must FILTER OUT irrelevant information to attend to stimuli of interest

2 Concepts of Filtering Theory

1) Dichotic Listening: The presentation of TWO DIFFERENT messages presented at the SAME time

EXCEPTIONS: Similarity of info, physical property of message (same intonation, voice, etc.) or level of meaningfulness

2) Stroop Effect: Double conflicting stimulus—must IGNORE the meaning of a word to attend to the task

External Factors

1) Intensity + Size

2) Contrast + Novelty
3) Repetition
4) Movement

Internal Factors

1) Motives + Needs (What do you need in the moment?)
2) Preparatory Set (Personal factors, prior experience with presented material)

3) Interest
4) Emotional State + Personality

Perceptional Organization

The process of COMBINING sensory objects into PERCEPTUAL OBJECTS—making sense of the visual world

Gestalt

Seeing the objects as part of a WHOLE

3 Ways of Perceptual Organization

1) Perceptual Grouping: Perceiving stimuli and grouping them into PATTERNS

2) Organizational Patterns: Seeing PATTERNS and not CLUSTERS of STIMULI

3) Follow the 7 Laws of Perceptual Organization which are INNATE

7 Laws of Perceptual Organization

1) Figure + Ground
2) Proximity + Nearness
3) Similarity + Likeness

4) Closure (Perceive a WHOLE object when it is not depicted as whole)

5) Continuity
6) Symmetry

7) Common Fate (Elements are perceived as moving TOGETHER as an organized group)

Perceptual Constancy (Stability)

A tendency to perceive objects as RELATIVELY STABLE/UNCHANGING despite the changing sensory input

Size Constancy

Perceiving an object having the same SIZE regardless of DISTANCE

Ames Room

A titled room illusion where objects appear to be larger/smaller than they SHOULD be

EXCEPTION to size constancy

Key is distance + angle

Honi Phenomenon

Exception to the AMES ROOM

People will experience LESS size distortion when looking at a familiar person

Shape Constancy

The tendency to perceive objects as having the same SHAPE regardless of the angle you look at the object from

Brightness + Color Constancy

Visual objects appear CONSTANT in their degree of whiteness/blackness/greyness regardless of the INTENSITY OF LIGHT

Accommodation

The role played by the muscles in/around your eyelines
Looking at NEAR objects: Round out
Looking at FAR objects: Flatten out

Monocular Depth Perception

Stimuli that operate INDEPENDENTLY on each eye

Linear Perspective

FARTHER objects are from eye, CLOSER they appear to each other

Clearness + Aerial Perspective

The more CLEAR we see an object, the CLOSER it appears

Interposition

An object PARTIALLY BLOCKED by another seems FARTHER AWAY than obstructing object
(EX: Skyscrapers)

Shadows + Light

Far objects seem DARKER
Near objects seem BRIGHTER

Texture + Density Gradient

Detailed/rough textures seem CLOSE

Fine/soft textures seem FAR

Movement

Differences in the SPEED of movement across your eyes cues to DISTANCE/DEPTH

Binocular Depth Perception

Stimuli that depend on BOTH eyes interacting at the SAME time
Closer the object, the more DISPARITY ~2.5 inches due to distance of the eyes

Convergence

The joining of different images produced by the retinal disparity so that a SINGLE image is seen

Stratoscopic Motion

Rapid presentation of SEPARATE images, each SLIGHTLY different from PRECEDING one
Goal = Continuous motion

Autokinetic Motion

Small stationary spot of light in a COMPLETELY DARK room will appear to move if you FIXATE on it for a period of time
Due to a lack of visible boundaries to compare light to

Induced Motion

Vision INCORRECTLY tells us that a figure is moving THROUGH the ground
Ex: Sun behind a cloud

Phi Phenomenon

If you arrange two spots of light in a COMPLETELY DARK room and alternatively illuminate them, this gives the affect of a single light MOVING from one position to another

10 Factors that AFFECT Perception

1) Motivation: One’s needs/desires

2) Expectation: Knowing in ADVANCE what one is supposed to perceive

3) Personality: People project their emotions/needs/wants on to a figure (Projective tests)

4) Sensory Deprivation: Whether for a short, long, or critical period of time

5) Drug-Induced Experience

6) Extra Sensory Perception (ESP): Test with playing cards, those with ESP ranged from 4-8 points (number of correct guesses on what a card was)

7) Cultural Experiences

8) Learning: Size constancy develops around age 8

9) Maturation: Nature vs. Nurture

• Nativists: Everything is INNATE (Gestalt)

• Impiracists: Everything is EXPERIENCE
  

• FANTZ Experiment: After 6 months, take mobile down—children perceive the ENTIRE face

• VISUAL CLIFF EXPERIMENT: By 14 months, a baby has developed DEPTH PERCEPTION

10) Context

Illusions

An incorrect perception

Muller/Lyre: Line segments arrowhead illusions