Perception

The process of organizing, and interpreting sensory information enabling us to recognize meaningful objects and events Example:

Top Down Processing Processing information from the senses with higher level mental processes using our Using your background knowledge to fill in the gaps Example: – Closure Happy Birthday to you, happy birthday to you, happy birthday dear Aaron, happy birthday to…

Gestalt Psychology Gestalt - mind tends to perceive objects as a unified wholes rather than the bits and pieces that make up those wholes and patterns. – Examples: Necker cube – Do you see circles with white lines or a cube? Do you see the x in the center in the front edge or the back?

Figure Ground Relationship Figure –ground – organization of the visual field into Example:

Grouping Grouping – tendency to organize stimuli into coherent Examples – pictures on the right closure

Grouping Proximity - group objects that are close together as being part of same group Example – three girls standing in the hallway next to each other Similarity - objects similar in appearance are perceived as being part of same group Example – black toy poodles and red toy poodles are seen as two different groups of dogs Continuity - objects that form a continuous form are perceived as same group Example – grout between tiles is seen as a single straight line Connectedness – objects that are uniform and linked are perceived as a single unit Example – beads on a necklace Closure - how humans fill in visual gaps in order to perceive disconnected parts as a whole object. Example – IBM Logo

Depth Cues Depth Perception

Development of Depth Perception in Humans Is depth perception innate or gained through experience? Visual Cliff Experiment - Eleanor Gibson

Depth Perception Cues Monocular cues – depth cues that need only Used to judge distance of object Examples: – Interposition – Relative size – Linear Perspective – Relative height – Texture gradient – Shadowing – Relative Motion Binocular cues – depth cues that Used to judge distance of object Examples: – Retinal Disparity – Convergence

Interposition closer objects cut off the view of part or all of a more distant one

Relative Size the smaller of two objects is perceived as farther away

Relative Height objects higher in our field of vision furthest away

Linear Perspective provides a cue to distance when parallel lines seem to converge in the distance

Texture Gradient closer objects have a more distinct texture and farther away objects appear more densely packed and smooth

Light and Shadow brighter ones seems closer and dimmer one seems further away

Relative Motion objects beyond the fixation point appear to move with you, objects in front of the fixation point appear to move backward

Picture #1

Binocular Cues Binocular cues – Examples: Retinal Disparity - the difference between the visual images that each eye perceives because of the different angles in which each eye views the world. 3-D Movies – simulate retinal disparity Convergence - as an object comes closer our eyes have to come together to keep focused on the object.

Perceived Motion Perceived Motion by the of the image on our retina – objects Stroboscopic effect – continuous movement in a rapid series of slightly varying images – Example: Phi phenomenon – an allusion created when two or more adjacent lights blink on and off in quick succession Example:

Constancy Perpetual constancy – perceiving objects as Examples Shape Constancy Size Constancy Brightness Constancy Color Constancy

Perceptual Constancy Shape constancy – perceive objects as having a constant shape even though

Perceptual Constancy Shape Constancy illusion– some times we perceive the shape of something to change with the angle of our view

Perceptual Constancy Size constancy – perceive objects as having a constant size even though

Perceptual Constancy Size constancy illusion– sometimes we perceive objects as having a changing size because of the Moon Illusion Ponzo Illusion

Ames Room

Lightness Constancy Lightness constancy aka Brightness constancy – perceiving an object as having constant lightness even though Depends on… – Relative luminance – the amount of light an object reflects relative to its surroundings

Color Constancy Color constancy – familiar objects are perceived to be the same color even if Depends on what we’re comparing it to… – Surrounding context – perceived color is influenced by its surrounding context – Surrounding objects – perceived color is influenced by its surrounding objects Example: color of these blue circles are identical. Because the brain computes the color of an object relative to its context, the perceived color changes Apple in a bowl of fruit appears to be red even if the light changes because the brain perceives (expects) it to be red.

Warm-up Explain to your partner the idea of constancy – Discuss all 4 types of constancy and give an example of each – Discuss one illusion we discussed Friday and why the illusion occurs Moon Illusion Ponzo Illusion Ames Room illusion Brightness illusion (checkerboard) Color illusion (yellow and blue cube)

Sensory Deprivation and Restored Vision Experiments on sensory deprivation – Brains cortical cells don’t develop normal connections to – Critical period - specific time during which an organism has to experience stimuli in order to progress through developmental stages properly. There is a

Perceptual Adaptation Perceptual adaptation – the ability to adjust to artificially displaced or inverted visual field Demonstrates the impact of Example: – Displacement goggles -

Perceptual Interpretation How we interpret things…is it nature or nurture? Experience helps us construct perception: critical period in perception (also nature), perceptual adaptation, perceptual set, schemas, and context effects are all influenced by experience

Perceptual Set Perceptual set (aka mental predisposition) – mental predisposition to perceive one thing and not another – greatly influence what we perceive – Schemas – organized units of knowledge about objects and events –a file folder about a topic that is based on our experience. They help us interpret unfamiliar info/ambiguous situations Examples:

Context Effects Context effects – perceptual set can be influenced by the context (expectations and emotions, and motivations) Examples: –

Perception is a Biopsychosocial Phenomenon

Is There Extrasensory Perception?

Parapsychology

Claims of ESP Parapsychology – study of paranormal phenomena including Extrasensory Perception – claim that perception can occur apart from sensory input Examples: – Telepathy – mind to mind communication – Clairvoyance – perceiving remote events – Precognition – perceiving future events Psychokinesis (PK) – mind over matter (levitation)