Motion Perception, Perceptual Constancy, Perceptual Interpretation,

and ESP (it’s not real…)

Motion Perception & Perceptual Constancy

• Which car is bigger?• What is in my hand?

Motion Perception• Stroboscopic movement

- movementisexperienced whentheobjectappearstoundergoachangeinitslocation.displayingaseriesofstillimages,givingtheperception ofcontinualmotion. Thinkstrobelightorhowcartoonswork.

• Phi phenomenon - an illusion of movement created when two or more adjacent lights blink on and off in quick succession.

• Perceptual Constancy - perceiving objects as unchanging (having consistent shapes, size, lightness, and color) even as illumination and retinal images change.

Shape and Size Constancies

• Shape constancy – perceive the form of familiar objects as constant even while our retinal image of it changes

Shape and Size Constancies• Size constancy – we perceive objects as having a

constant size even when our distance from them varies – Connection between perceived distance and perceived size

• Moon Illusion – why does the moon look bigger when closer to the horizon?

• Monster Illusion• Ponzo Illusion

Take away distance cues-look through a tube

Shape & Size Constancy• Put your left hand in front of

your face• Move it back and forth

– Does it seem to grow and shrink?

• Probably only a little• Now put a finger in front of

your hand• Focus on the finger• Move the hand behind your

finger back and forth– What happened?

Ames Room

Lightness Constancy

• Lightness constancy –we perceive an object as having a constant lightness even while its illumination varies– AKA Brightness

constancy– Relative luminance –

amount of light an object reflects relative to its surroundings

– Square A looks darker than square B because of surrounding context, but they are the same

Color Constancy

• Color constancy - perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object.– Surrounding context &

objects

Perceptual Organization, Constancy, & Other Senses

• Do you hear clocks ticking as grouped sounds? (TICK-tick, tick-tock – rather than just tick tick tick tick…)

• Do unfamiliar languages sound like one long, continuous word? Can you tell when one word stops and another begins?

• THEDOGATEMEAT– The dog ate meat – The do gate me at

• Which did you arrange this as? – Because of: perceptual interpretation – our last section

of the unit…

AP Psych Unit 4.5 Perceptual Interpretation & ESP

1. Can you recall a time when your expectations have predisposed how you perceived a person or people?

2. Could you get through your day if you saw everything upside down?

3. First day in a new pair of glasses – or if you have ever put on a friend’s glasses (if you have 20/20) – how does it feel?

4. Have you ever experienced ESP? Explain.

Sensory Deprivation &

Restored Vision

• If a man born blind, and now adult, was taught by his touch to distinguish between a cube and a sphere – could he, if made to see, visually distinguish between the 2?

• Experiments on sensory deprivation - people with cataracts that could then see later in life– Just like the man in this picture,

humans have a critical period in early life to gain the ability for certain top-down processing in perception.

– if a sense is gained later in life, critical period was missed, they have problems with perception

– But some sensory restrictions later in life do no damage

Perceptual Adaptation• Perceptual adaptation - in

vision, the ability to adjust to an artificially displaced or even inverted visual field.

• Think about when you first get a new pair of glasses – you feel a little dizzy or your vision is off, but in a few days, your vision is perfect again

Perceptual AdaptationVisual Distortion Goggles

• Glasses that can shift everything you see drastically to the left or right

• Within a few minutes you can adapt!

• Remove the lenses – aftereffect• Upside-down inversion goggles –

experiment proved you can even adapt to that change after 8 days

Perceptual Set• Perceptual set - a mental disposition to perceive

one thing and not another – the mental predisposition greatly influences what we perceive (top-down).

• Based on our experiences, assumptions, & expectations

• Once we have a wrong idea about reality, we have trouble seeing the truth

• Read the piece of paper the teacher gives you and then write down what you see in the next slide:

• What is the picture in the middle?– If you look only at the picture on the left first,

you see a saxophone player– If you look only at the picture on the right first,

you see a woman

What do you see here?•Loch Ness monster OR a log?•When the media tells you it’s a monster, that’s what you see.•But are there ripples of water coming from the body? Think about a log before you look at it, and that is what you will see•(Do you believe in Nessy?)

Perceptual Set is Similar to Priming• What word do these letters spell?

– F O L K• What about these?

– C R O A K• And these?

– S O A K

• What do you call the white of an egg?

Schemas• Study shows that fries served in

a McDonald’s bag rather than a plain white bag are perceived to be more delicious

• Schemas – our pre-existing experiences form concepts / schemas that help organize and interpret new info and help with top-down processing

• Determines perceptual sets

Would you pay $28,000 for this?

• Schemas & Perceptual Sets are responsible for people claiming to see random facial patterns in the moon, food, etc..

Context Effects:• “—eel is on the wagon”• “—eel is on the orange”• Does the player in yellow look short?• Does the chasing monster in back look

aggressive? Does the chased monster in front look scared?

• Is the box on the floor or hanging from the ceiling?

• Need a baby to wear boy colors to know it’s a boy? Difficult without context?

Culture & Context Effects1. What is above the woman’s head?2. Where are these people?

Culture & Context Effects1. Westerners: window. East Africans: Box on her head2. Westerners: corner of a room. East Africans: under tree

Emotion and Motivation

• Walking destinations seem farther away when we are already tired

• Hills look steeper if we are wearing a heavy backpack

• Targets seem farther away if we are throwing a heavier item at it

• Baseball players say the ball seems bigger if they are hitting well

Motivation

• If you are told you will be rewarded for seeing a farm animal, you will see a horse

• If you are told you will be rewarded for seeing a sea animal, you will see a seal

Emotions• Teachers will be more strict

with students that have a reputation for being bad in the past, regardless of their current behavior or recent maturity

• Referees call fouls more often on players with a history of aggressive behavior

• When driving– you hate pedestrians, when walking –you hate drivers!

Perception is a BiopsychosocialPhenomenon

Claims of ESP• Parapsychology - the study of paranormal

phenomena (psi), including ESP and psychokinesis.

• Extrasensory Perception (ESP) - the controversial claim that perception can occur apart from sensory input– Telepathy – mind to mind

communication – sending thoughts to others or reading thoughts

– Clairvoyance – perceive remote events happening now

– Precognition – tell the future• Psychokinesis (PK) – mind over matter -

levitation

Parapsychology

Premonitions or Pretensions?• Why don’t psychics predict

lotteries? Make billions in the stock market? Predict 9/11?

• Psychics predictions rarely come true, only by chance– Nostradamus – even said

himself that his predictions could maybe be applied to events after they happen and interpreted to match that strange event

What About Déjà Vu?

• Do your dreams predict the future?• Do they only seem to because we

are more likely to recall dreams that seem to come true?

• What about the thousands of other dreams that don’t come true and that we never think about? Is it just by chance or do the dreams predict?.....

Putting ESP to Experimental Test

• ESP Experiments• Psychics are always

proved wrong in the lab• They are not on stage,

controlling an audience