We do not perceive the world how it really is,

but as it is useful for us to perceive it.

PerceptionPerceptionThe process of organizing and interpreting information we get from our senses

•enables us to recognize meaningful objects and events.

In transformingsensations into perceptions,

we create the meaning

Selective AttentionSelective Attention

• Any moment we focus our awareness on only a limited aspect of all that we experience

• Example– directions video

Cocktail Party EffectCocktail Party Effect

• Ability to attend selectively to only one voice among many

Visual CaptureVisual Capture

The dominance of vision over other sense modalities, such that what is felt or heard conforms to what is seen.

Perceptual IllusionsPerceptual Illusions

• Once we have attended to certain stimuli, how do we organize them into meaningful perceptions?

• Dalmatian Picture

Perceptual Illusions

Perceptual Illusions

Perceptual Illusions

Perceptual Illusions

Perceptual Illusions

Perceptual Illusions

Perceptual Illusions

Visual CaptureVisual Capture

• When vision competes with other senses, vision usually wins- known as visual capture

• For example- watching a movie, in theatres we believe the sound is coming from the screen where people are talking, when really, it’s not

Perceptual OrganizationPerceptual Organization

• To transform sensory information into meaningful perceptions, we must organize it

• We must perceive objects as distinct from their surroundings, see them as having a meaningful and constant form, and discern their distance and motion.

GestaltGestalt

• German scientist became intrigued with how the mind organizes sensations into perceptions

• Given a cluster of sensations, the human perceiver organizes them into a gestalt

• Described principles by which we organize our senses into perceptions

Gestalt Psychology• Gestalt means “an organized whole”• These psychologists were concerned with how

and why we GROUP objects together.• They stated that humans can not help but

perceive stimuli in groups rather than individual or isolated elements

This explains why we see a cube and not a set of isolated holes or circles

Perceptual Organization: Gestalt

Grouping the perceptual tendency to organize stimuli

into coherent groups Grouping Principles

proximity--group nearby figures together similarity--group figures that are similar continuity--perceive continuous patterns closure--fill in gaps connectedness--spots, lines, and areas are

seen as unit when connected

Perceptual Organization: Grouping Principles

ProximityProximity

• We group nearby figures together.

Proximity

• Grouping nearby figures together

3 sets of parallel lines not six separate lines

SimilaritySimilarity

• Figures similar to each other we group together.

Similarity

• Grouping together figures that are similar to each other

9 separate shapes9 separate shapesOrOr

Two columns and oneTwo columns and oneColumn?Column?

ContinuityContinuity

• We perceive smooth, continuous patterns rather than discontinuous ones

Continuity

• Perceiving smooth continuous patterns not discontinuous ones

ConnectednessConnectedness

• When they are uniform and linked, we perceive spots, lines, or areas as a single unit

Perceptual Organization: Perceptual Organization: ClosureClosure

We fill in gaps to create a complete, whole object

Closure

• Filling in gaps to create a complete, whole object

Perceptual Organization

Figure and Ground--organization of the visual field into objects (figures) that stand out from their surroundings (ground)

Warm-UpWarm-Up

1. What is perception?

2. Give an example of bottom-up processing

3. Explain Gestalt Psychology and give one example of grouping.

4. Explain Cocktail Party Effect

PerceptionPerceptionOur perceptions are affected by Our perceptions are affected by

the biology of our sensory the biology of our sensory systems, but also by our previous systems, but also by our previous

experiences and cultural experiences and cultural expectations.expectations.

Or in other words our…Or in other words our…

SchemasSchemas

Take a moment to write down a few adjectives to describe each person based

on their pictures.

A B

Which one is better looking?Which one is better looking?

Perception is also often based Perception is also often based on…on…

Perceptual SetPerceptual Set A bias to perceive one thing and not another when A bias to perceive one thing and not another when

looking at things in our worldlooking at things in our world Sort of the same thing as a mental setSort of the same thing as a mental set So in some ways it can cause us to make errors in So in some ways it can cause us to make errors in

judgments when we are trying to perceive the world judgments when we are trying to perceive the world through our sensesthrough our senses

• What you see in the center is influenced byyour perceptual set

What do you see?What do you see?

Perceptual Set

Bill Clinton and who?

Perceptual Set-Schemas

Which is the real Madonna?

Perceptual Set-Schemas

• When we hold the eyes as a constant it is difficult to identify the correct Madonna. Now that the image is rotated it is easy to tell the difference.

Perceptual IllusionsPerceptual IllusionsUsed to reveal how we normally organize Used to reveal how we normally organize

and interpret sensationsand interpret sensations

Optical or Visual IllusionsOptical or Visual IllusionsDiscrepancies between the appearance of a Discrepancies between the appearance of a

visual stimulus and its physical realityvisual stimulus and its physical reality

Form Perception

• Figure-Ground

Relationship • When we look at objects we

see the object as the figure and its surroundings as the background – Airplane in the sky

Depth PerceptionDepth Perception The ability to see objects in three The ability to see objects in three

dimensions although the images that dimensions although the images that strike the retina are two dimensional.strike the retina are two dimensional.

Allows us to judge distance.Allows us to judge distance.

Perceptual OrganizationPerceptual OrganizationDepth PerceptionDepth Perception

Visual CliffVisual Cliff

Used to test infants depth perception

How do we transform two-How do we transform two-dimensional objects to three-dimensional objects to three-

dimensional perception?dimensional perception?

Binocular CuesBinocular Cues: : depth cues that depend on two depth cues that depend on two

eyeseyes

•Monocular CuesMonocular Cues: •depth cues that depend on one eye

Perceptual Organization: Depth Perception

Binocular cues retinal disparity

images from the two eyes differ

closer the object, the larger the disparity

convergence neuromuscular

cue two eyes move

inward for near objects

Perceptual Organization: Depth Perception

Monocular Cues relative size

smaller image is more distant

interposition closer object blocks distant object

relative clarity hazy object seen as more distant

texture coarse --> closefine --> distant

Perceptual Organization: Depth Perception

Monocular Cues (cont.) relative height

higher objects seen as more distant

relative motion closer objects seem to move faster

linear perspective parallel lines converge with distance

relative brightness closer objects appear brighter

Linear Perspective

Parallel lines seem to converge with distance.

Linear Perspective at WorkLinear Perspective at Work

•Relative SizeRelative Sizeif we know that two objects are similar in size, the if we know that two objects are similar in size, the

one that looks smaller is farther awayone that looks smaller is farther away

Relative Size

InterpositionInterpositionif something is blocking our view, we perceive it if something is blocking our view, we perceive it

as closeras closer

Motion PerceptionMotion Perception

What tools do we use to perceive What tools do we use to perceive motion…motion…

Stroboscopic movementStroboscopic movement Perceiving continuous movementPerceiving continuous movement ExampleExample

• MoviesMovies

Flip Book Example

Phi Phenomenon• An illusion of movement created when two or more

adjacent lights blink on and off in succession.

CataractsCataracts

•Definition: an eye disease in which the lens becomes covered in an opaque film that affects sight, eventually causing total loss of sight.

ESPESPThree types of ESP:

1. Telepathy- mind to mind communication

2. Clairvoyance- perceiving events as they are taking place

3. Precognition- perceiving future events

Also associated with ESP, psychokinesis (“mind over matter”