Ted Talk: Optical Illusions – I think, I see, I wonder…

Perception Continued!

Get Out Your Notebooks!

Sense Perception‘Two thirds of what we see is behind our eyes.’

- Chinese Proverb

Sensation - material gathered from world

Interpretation - provided by our minds

Selectivity The role of the unconscious Expectations

Perception is Complex

You cannot process all of the sense data you are surrounded by

Your mind SELECTS which details to attend to. Ex. Traffic outside, computer hum, a roach in the

floor How does the mind ‘decide’ what to be

conscious of? Intensity and contrast are two seemingly

objective factors that may have evolutionary origin

Selectivity

Mood and Interest may affect selectivity Ex. Three friends walking trails at Radnor Lake,

an argument over music If your family buys a new car, you will

immediately start to notice every car in traffic that is similar

If a woman becomes pregnant, she will notice every pregnant woman

Subject Selectivity

Take one of the following phenomena and describe how it might be seen through the eyes of the following people:

a. a child dying in poverty as seen by a doctor, an economist, a social worker, the child’s father.

b. a sunset as seen by a religious figure, a physicist, a painter, a farmer

c. a tree as seen by a biologist, a logger, an environmentalist, a native American.

Time-Out!

How much of ‘seeing’ is done with our eyes?

What is the difference between ‘seeing’ and ‘perceiving’?

Knowledge Issue Concepts: Context, Expectations, Visual Grouping, Figure/Ground, Unconscious Activity

Optical Illusions

The way we see something depends partly on the context in which we see it.

Consider a man holding a bloody knife…how could context change our perception of what are eyes ‘see’?

Issue #1: Context

What we expect to see influences what we do see

This perceptual error is far from uncommon

Look at the image to the right…is there anything wrong?

Issue #2: Expectations

What cards do you see?

Issue #2: Expectations

We have a natural tendency to look for meaning in what we see and to group our perceptual experiences together into shapes and patterns

Shapes in clouds Man in the Moon

Issue #3: Visual Grouping

We tend to ‘highlight’ certain aspects of what we see (‘figure’) and treat the rest as background (‘ground’)

Allows reading and other forms of focused attention

Issue #4: Figure/Ground

We suffer not only from visual illusions, but also from illusions with each of our other senses. Can you give some examples of illusions with hearing, touch, taste, and smell?

Time-Out!

Many interpretations we routinely make are on an unconscious level

Ex. Image of someone approaching from down a hallway

Ex. Our face in the mirror

Issue #5: Role of the Unconscious