What is the World Like What is the World Like

for Other People?for Other People?

Perception and RealityPerception and RealityThings Are Not Always Things Are Not Always

As They Seem...As They Seem...

What is the World Like What is the World Like for Other People?for Other People?

OverviewOverviewVantage Point Vantage Point

Line of Sight and Refraction ExperimentsLine of Sight and Refraction ExperimentsColor Blindness TestsColor Blindness TestsRose-colored Glasses Rose-colored Glasses

Thought Experiment Thought Experiment Real-world Experiments Real-world Experiments

Blindsight and Neglect PatientsBlindsight and Neglect PatientsHomework Essay:Homework Essay:

Thought ExperimentsThought Experiments

Vantage PointVantage Point

This is probably very obvious but it is a very This is probably very obvious but it is a very important limit upon our ability to perceive important limit upon our ability to perceive reality correctly:reality correctly:

Where you are relative to something else Where you are relative to something else makes a difference.makes a difference.

For example, if you are looking down on a soft For example, if you are looking down on a soft drink can it looks different than if we view it drink can it looks different than if we view it from the side.from the side.

Line of SightLine of Sight

We can only see things that are not obstructed by We can only see things that are not obstructed by something else.something else.

We can determine if something is obstructed by We can determine if something is obstructed by drawing a straight line from our eyes to the drawing a straight line from our eyes to the object.object.

Whatever we can draw a straight line to without Whatever we can draw a straight line to without it hitting anything else is in our it hitting anything else is in our line of sightline of sight

This means that two people can have different This means that two people can have different perceptions of reality depending upon where perceptions of reality depending upon where they are seeing it from.they are seeing it from.

RefractionRefraction

Fill out the handout as you conduct the refraction Fill out the handout as you conduct the refraction experiment.experiment.

Light Refraction Experiment Light Refraction Experiment

(1) Make experimental observations (e.g. (1) Make experimental observations (e.g. drawings) of light refraction of a pencil in drawings) of light refraction of a pencil in water from different angles.water from different angles.

(2) Think about additional methods of testing (2) Think about additional methods of testing whether pencil is really bent.whether pencil is really bent.

Refraction DiscussionRefraction Discussion

Did the pencil look the same or different when Did the pencil look the same or different when looking at it from different angles?looking at it from different angles?

Which of these angles is correct (the way the Which of these angles is correct (the way the pencil is really shaped)?pencil is really shaped)?

How can we test to see if the water really bends How can we test to see if the water really bends the pencil or if we are mistaken?the pencil or if we are mistaken?

Dot Numbers:Dot Numbers: Do You See Any Numbers?Do You See Any Numbers?

Dot Figures: Are any of these objects Dot Figures: Are any of these objects in the bigger picture? Which one(s)?in the bigger picture? Which one(s)?

Perceptual RangePerceptual Range

Normal humans can only see light that is in the Normal humans can only see light that is in the visible light spectrumvisible light spectrum

This is very similar to only being able to hear This is very similar to only being able to hear sounds in the audible frequency range sounds in the audible frequency range (20 to 20,000Hz); some animals (like dogs) (20 to 20,000Hz); some animals (like dogs) can hear high pitched sounds that we cannotcan hear high pitched sounds that we cannot

Some people have a disorder of their eyes called Some people have a disorder of their eyes called red-green color blindness so that red and green red-green color blindness so that red and green look the same to them. Their perceptual range look the same to them. Their perceptual range is smaller than other people.is smaller than other people.

Rose-colored GlassesRose-colored Glasses

What would it be like if we always had rose What would it be like if we always had rose (red) colored glasses on?(red) colored glasses on?

What would Red look like to us? How about What would Red look like to us? How about Blue? Think about it…Blue? Think about it…

Now pick up the transparency in front of you Now pick up the transparency in front of you and look at different colored objects through it.and look at different colored objects through it.

Can you still tell a difference between the colors Can you still tell a difference between the colors (red and blue, for example)?(red and blue, for example)?

How about the difference between red and grey?How about the difference between red and grey?

Color ChartColor Chart

Patients with Brain InjuryPatients with Brain InjuryWhat is the difference between the pictures on the left and the copies of them made on the right?

More Drawings by More Drawings by Spatial Neglect PatientsSpatial Neglect Patients

What is the difference between the drawings on the left and the copies of them made on the right?

Patient Asked to Patient Asked to Cross Out All LinesCross Out All Lines

What is the pattern of lines being crossed out?

Neglect DiscussionNeglect DiscussionHow would you describe what is happening to these How would you describe what is happening to these

patients with brain injuries?patients with brain injuries?

It is not that they can’t see things on the left at all:It is not that they can’t see things on the left at all:

If their eyes did not work all they would have to do is If their eyes did not work all they would have to do is move the paper to the right and look at the side they move the paper to the right and look at the side they could not see.could not see.

These patients are unaware that these pictures or These patients are unaware that these pictures or objects have left sides (even though they have all objects have left sides (even though they have all seen these objects (clocks or flowers) normally before seen these objects (clocks or flowers) normally before their accidents).their accidents).

Consciousness Consciousness

ConsciousConscious – The things that you are actively – The things that you are actively aware of in your mind (it is not the same thing aware of in your mind (it is not the same thing as your as your conscienceconscience; which is your moral sense); which is your moral sense)

SubconsciousSubconscious – The things that are going on in – The things that are going on in your mind that you are not actively aware of your mind that you are not actively aware of (may or may not become aware of them later)(may or may not become aware of them later)

UnconsciousUnconscious – When you are in a condition – When you are in a condition when you are not aware of anything going on when you are not aware of anything going on in the world or your mindin the world or your mind

ConclusionsConclusions

Is everything that is going on in a person’s mind Is everything that is going on in a person’s mind conscious or are some things subconscious? conscious or are some things subconscious?

Is your perception of the world the same as Is your perception of the world the same as everyone else’s even when observing the same everyone else’s even when observing the same thing or situation? Elaborate.thing or situation? Elaborate.

Does information coming to your sense organs Does information coming to your sense organs (like your eyes) mean that the information (like your eyes) mean that the information becomes conscious to you?becomes conscious to you?

What evidence do you have to support these What evidence do you have to support these conclusions?conclusions?

Mysterious Case of BlindsightMysterious Case of Blindsight

A person has an injury to the parts of the brain that A person has an injury to the parts of the brain that processes most (but not all) of the visual information processes most (but not all) of the visual information from the eyes (but his eyes are fine).from the eyes (but his eyes are fine).

When asked whether he can see anything, the person When asked whether he can see anything, the person reports they are totally blind (cannot see anything).reports they are totally blind (cannot see anything).

When the person is told to guess what they were shown When the person is told to guess what they were shown he/she does much better than pure chance.he/she does much better than pure chance.

How is this similar to Neglect patients? How is this similar to Neglect patients?

Essay HW question:Essay HW question:

What do these patients (Blindsight and Neglect) tell What do these patients (Blindsight and Neglect) tell us about the role the brain plays in perception?us about the role the brain plays in perception?