PerceptionPerceptionContact With the World Around Us

Lauren BiegertAIS/D 2009

Based on the Theory of Knowledge Course Companion

ByDombrowski, Rotenberg, Bick

Contact With the World Around Us

Lauren BiegertAIS/D 2009

Based on the Theory of Knowledge Course Companion

ByDombrowski, Rotenberg, Bick

The Five SensesThe Five Senses

HearingTasteTouch SmellSight

HearingTasteTouch SmellSight

How Does Perception Work?

How Does Perception Work?

We have sense receptors in different parts of our bodies, as well as internal physical receptors for awareness of our own bodily sensations such as hunger, pain and arousal.

We have sense receptors in different parts of our bodies, as well as internal physical receptors for awareness of our own bodily sensations such as hunger, pain and arousal.

Three-fold processThree-fold process

1. Our sense receptors are stimulated by sensory information

2. The brain translates this sensory information into sensations such as sound, taste, temperature, pressure, smell or sight.

3. Higher centers in the brain either ignore or recognize the sensations and their meanings, based on neuronal networks of past association and expectation.

1. Our sense receptors are stimulated by sensory information

2. The brain translates this sensory information into sensations such as sound, taste, temperature, pressure, smell or sight.

3. Higher centers in the brain either ignore or recognize the sensations and their meanings, based on neuronal networks of past association and expectation.

Our Senses Are SelectiveOur Senses Are Selective

We do not sense all the stimuli that we’re potentially able to sense.

Why?

We do not sense all the stimuli that we’re potentially able to sense.

Why?

An Experiment An Experiment

Close your eyes and listen carefully to all the sounds around you for one full minute.

Which sounds were you not aware of prior to this exercise? Why not?

Close your eyes and listen carefully to all the sounds around you for one full minute.

Which sounds were you not aware of prior to this exercise? Why not?

Let’s Try It AgainLet’s Try It Again

For one minute close your eyes and concentrate on your sense of touch.

What sensations were you unaware of before this exercise? Why?

For one minute close your eyes and concentrate on your sense of touch.

What sensations were you unaware of before this exercise? Why?

Imagine that you are walking by yourself at night. Suddenly you

become aware that you are not alone. You feel a surge

of adrenaline. What sensations might you have

experienced that would have allowed you to recognize danger?

Imagine that you are walking by yourself at night. Suddenly you

become aware that you are not alone. You feel a surge

of adrenaline. What sensations might you have

experienced that would have allowed you to recognize danger?

The Word “Perception” is Ambiguous.

The Word “Perception” is Ambiguous.

We commonly use it to include our entire understanding of something, including our opinions.

We may say that we “perceive” something as desirable or dangerous, even though we don’t receive a value such as “desirable” through our senses.

We commonly use it to include our entire understanding of something, including our opinions.

We may say that we “perceive” something as desirable or dangerous, even though we don’t receive a value such as “desirable” through our senses.

Often we use the word “perception” as roughly equivalent to our conception (or ideas) about something.

Although it is difficult to separate physical perception from our whole understanding, attempting to restrict our attention to sense perception will help us as it will allow us to become more aware of the interplay between perception and conception, and how they come together to shape our knowledge.

Often we use the word “perception” as roughly equivalent to our conception (or ideas) about something.

Although it is difficult to separate physical perception from our whole understanding, attempting to restrict our attention to sense perception will help us as it will allow us to become more aware of the interplay between perception and conception, and how they come together to shape our knowledge.

We Don’t Perceive the World As It is, Only As We

Perceive It.

We Don’t Perceive the World As It is, Only As We

Perceive It.Bats and Dolphins use sonar for navigation.Homing Pigeons and Salmon have magnetite

deposits in their bodies that enable them to detect the Earth’s magnetic fields enabling them to find their way home.

Even the senses we share with other animals we possess to different degrees: We don’t smell as well as dogs, or see as well as eagles.

Bats and Dolphins use sonar for navigation.Homing Pigeons and Salmon have magnetite

deposits in their bodies that enable them to detect the Earth’s magnetic fields enabling them to find their way home.

Even the senses we share with other animals we possess to different degrees: We don’t smell as well as dogs, or see as well as eagles.

Our Knowledge is LimitedOur Knowledge is Limited

Not only is our knowledge dependent on our cultures, experiences and education, but on an even more basic level, we are dependent on our perception abilities as humans.

And on our interpretations.

Not only is our knowledge dependent on our cultures, experiences and education, but on an even more basic level, we are dependent on our perception abilities as humans.

And on our interpretations.

Our interpretation of sensations is likewise dependent on our human brains.

We see pink roses or taste sweet honey and it seems to us that the pinkness and the sweetness are in the roses and in the honey, rather than in their effect upon us.

But they’re really in our brains.

Our interpretation of sensations is likewise dependent on our human brains.

We see pink roses or taste sweet honey and it seems to us that the pinkness and the sweetness are in the roses and in the honey, rather than in their effect upon us.

But they’re really in our brains.

STIMULI SENSE RECEPTOR

SENSATION RESPONSE

ELECTROMAGNETIC ENERGY

EYES, RETINA LIGHT AND COLOREM RADIATION SHINING ON OBJECT RESULTS IN VISUAL PERCEPTION

“HEY, HERE’S THE BOOK I LOST!”

VIBRATIONS OR WAVES WITH A FREQUENCY BETWEEN 20 AND 20,000 HZ

EAR SOUNDTHE PRESENSE OF CERTAIN AUDITORY FREQUENCIES RESULTS IN AUDITORY PERCEPTION

“ I HATE THIS COLDPLAY SONG!”

CHEMICAL COMPOSITION

MOUTH, TASTE BUDS, CHEMORECEPTOR CELLS

SWEET, SALTY, SOUR, AND BITTERTHE PRESENSE OF CERTAIN COMPOSITIONS RESULTS IN TASTE

“MMMMMMM THESE COOKIES ARE CHOCOLATEY!”

ODOR MOLECULES NOSE, OLFACTORY RECEPTOR NEURONS

SMELLMOLECULE COMBINATIONS RESULT IN PERCEPTION OF SMELLS

“OH YUM, IS SOMEONE BAKING COOKIES?

PRESSURETEMPERATURE

SKINNERVE ENDINGS

HOT, COLD, TEXTURES, PRESSURE, PAINTHESE STIMULI RESULT IN TOUCH

“THIS COFFEE IS TOO HOT TO DRINK!”

Humans add to their sense perception with

technology

Humans add to their sense perception with

technology Night vision goggles X-ray machines Video cameras Microphones Ultrasound Compasses Thermometers Smoke detectors Sonar

Night vision goggles X-ray machines Video cameras Microphones Ultrasound Compasses Thermometers Smoke detectors Sonar

Perception varies from person to person

Perception varies from person to person

Synesthesia--some people can “smell” colors and “feel” tastes.

Wine tasters and perfume “noses” have extraordinary capabilities to sense certain things.

How do you know your sense of perception is “normal”?

Synesthesia--some people can “smell” colors and “feel” tastes.

Wine tasters and perfume “noses” have extraordinary capabilities to sense certain things.

How do you know your sense of perception is “normal”?

Receiving stimuli is only the first part.

Receiving stimuli is only the first part.

Our brains have to make sense of the stimuli.

Even when we are not aware of it, our brains are actively engaged in interpreting the stimuli they receive.

Our brains have to make sense of the stimuli.

Even when we are not aware of it, our brains are actively engaged in interpreting the stimuli they receive.

Read this passageRead this passage I cdnoult blveiee that I cluod aulaclty

uesdnatnrd what I was rdanieg. The phaonmneal poewr of the hmaun bairn! Aoccdnig to a rscheearch at cmabirgde uinervisity, it deons’t mtater what odrer the ltteers in a word are, the olny iprmoatnt tinhg is that the fsirt and lsat ltteer be in the rghit pacle. This is bcuase the hmuan mnid deos not raed evrey leettr by isletf, but the word as a wlohe. Azinmng! And I awlyas tuohght sleplnig was ipmorantt.

I cdnoult blveiee that I cluod aulaclty uesdnatnrd what I was rdanieg. The phaonmneal poewr of the hmaun bairn! Aoccdnig to a rscheearch at cmabirgde uinervisity, it deons’t mtater what odrer the ltteers in a word are, the olny iprmoatnt tinhg is that the fsirt and lsat ltteer be in the rghit pacle. This is bcuase the hmuan mnid deos not raed evrey leettr by isletf, but the word as a wlohe. Azinmng! And I awlyas tuohght sleplnig was ipmorantt.

Our brains translate stimuli into sensations such as temperature, scents, images and sounds., which are meaningless without the last step.

If you didn’t understand English, would that passage have made any sense?

Our brains translate stimuli into sensations such as temperature, scents, images and sounds., which are meaningless without the last step.

If you didn’t understand English, would that passage have made any sense?

The final stepThe final step

Stimuli are not processed by our brains as if they were blank slates. Rather the resulting sensations are being integrated,compared and contrasted with everything you’ve perceived before.

This process helps us recognize and interpret the sensations.

Stimuli are not processed by our brains as if they were blank slates. Rather the resulting sensations are being integrated,compared and contrasted with everything you’ve perceived before.

This process helps us recognize and interpret the sensations.

A TestA Test

Our brains make judgments based on previous experiences.

Which red line is longer?

Our brains make judgments based on previous experiences.

Which red line is longer?

Gestalt TheoryGestalt Theory

We tend to perceive objects as meaningful patterns or groups, rather than as collections of separate parts.

When you look at your friend, you recognize her face immediately, without being aware of all its separate components.

We tend to simplify visual information, grouping it in patterns that are easier to process. It works quite well for us, except that sometimes we recall what’s not there.

We tend to perceive objects as meaningful patterns or groups, rather than as collections of separate parts.

When you look at your friend, you recognize her face immediately, without being aware of all its separate components.

We tend to simplify visual information, grouping it in patterns that are easier to process. It works quite well for us, except that sometimes we recall what’s not there.

Find the face in the beansFind the face in the beans

And sometimes our senses play tricks on us.

And sometimes our senses play tricks on us.

Are A and B the same color?

Are A and B the same color?