mental construction of reality

The mental construction of The mental construction of realityreality

What is the link between What is the link between perception and reality?perception and reality?

Hermann Grid

Where are the grey dots? Not on the paper, so where?

What do you see?Where are

these ‘non-existent’ shapes?

What is going on?

sense data sense data

Brain works out what is the best story it can tell your mind based on the sense data

What ‘story’ is your brain telling you?

that the central area

is curved, three

dimensional?

What story is your brain telling you?

that the image is

three dimensional?

What is the real pattern here?

Does your brain ‘flip’ between the diamonds and the rectilinear pattern?

Imagine

1. How can this be as you could not hear the conversations?

2. What does this suggest about the way our brains work?

You are in a noisy room with lots of people

talking, including yourself. You can’t hear

the other conversations, but suddenly you

hear your name mentioned across the room.

1. Why do we not see small dark spots there?

2. What does this suggest about the way our brains work?

In each eye there is a blind spot. The blind

spot is a small area near the centre of the

visual field where the optic nerve leaves

the eye to go to the brain. There are no

light receptors in this small area (hence the

name blind spot).

1. How can this be?2. What does it suggest about the way our

brains work?

Professional tea tasters can distinguish between

literally thousands of brands of tea. Wine tasters

can tell you the grape, year, country, region,

vineyard and even which side of the valley a

particular bottle of wine has come from. But these

professionals have no more taste buds than you or

I do. They have no more nerves in their tongues,

and those they do have are not any more sensitive

than the norm.

Upside-down glasses

What happens when you wear upside-down glasses?2.At first?3.After some time?

The mental construction of realityThe mental construction of reality

Previous ExperiencePrevious Experience ReasonReason ExpectationExpectation EmotionEmotion Preconceived ideasPreconceived ideas

If the brain has to make sense of the sensory data, what does it use to make sense of this?

Should we trust eye-Should we trust eye-witnesses?witnesses?

Case of Ronald CottonCase of Ronald Cotton

13 mins

How accurate are memories?How accurate are memories?

2 mins

2 mins

2 mins Bugs Bunny Effect

The Case of Jean Charles de Menezes,The Case of Jean Charles de Menezes,killed at Stockwell Tube, July 2005 killed at Stockwell Tube, July 2005

Eyewitnesses saidEyewitnesses said Dressed in "baseball Dressed in "baseball

cap, blue fleece and cap, blue fleece and baggy trousers.“baggy trousers.“

wearing a large winter wearing a large winter coat, which "looked out coat, which "looked out of place“ in summer.of place“ in summer.

wearing a "bomb belt wearing a "bomb belt with wires coming out.“with wires coming out.“

jumped over the ticket jumped over the ticket barrier, ran down an barrier, ran down an escalator and tried to escalator and tried to jump on to a train.jump on to a train.

In factIn fact Dressed in jeans and Dressed in jeans and

light denim jacket, no light denim jacket, no tool bag or bomb belttool bag or bomb belt

Used his Oyster card Used his Oyster card to get through barrier, to get through barrier, did not jump over it or did not jump over it or runrun

The Case of Jean Charles de Menezes,The Case of Jean Charles de Menezes,killed at Stockwell Tube, July 2005 killed at Stockwell Tube, July 2005

Eyewitnesses saidEyewitnesses said Five shots heardFive shots heard Three shots heardThree shots heard Police challenged JCM Police challenged JCM

but he refused to obey but he refused to obey instructionsinstructions

Police shouted Police shouted “Everybody Out!”“Everybody Out!”

In factIn fact Police issued no warning Police issued no warning

or instructionsor instructions Police had been following Police had been following

JCM for about an hour as JCM for about an hour as he travelled from home on he travelled from home on foot and bus to Stockwellfoot and bus to Stockwell

was already on the was already on the ground, several police ground, several police officers piled on top of him officers piled on top of him when shotwhen shot

Eight shots, 7 to head 1 to Eight shots, 7 to head 1 to shouldershoulder

This lessonThis lesson

The mental construction of realityThe mental construction of realityShould we trust eye-witnesses?Should we trust eye-witnesses?

How is this relevant to us?• Confirmation Bias• Coherence test

HomeworkHomework

Read chapter 4 of text bookRead chapter 4 of text book Read “Two fish swimming along” by David Read “Two fish swimming along” by David

Foster WallaceFoster Wallace– What are its main points about perception and What are its main points about perception and

knowledge of the world?knowledge of the world?

Once Zhuangzi dreamt he was a butterfly, a butterfly Once Zhuangzi dreamt he was a butterfly, a butterfly

flitting and fluttering around, happy with himself flitting and fluttering around, happy with himself

and doing as he pleased. He didn't know he was and doing as he pleased. He didn't know he was

Zhuangzi. Suddenly he woke up and there he was, Zhuangzi. Suddenly he woke up and there he was,

solid and unmistakable Zhuangzi. But he didn't solid and unmistakable Zhuangzi. But he didn't

know if he was Zhuangzi who had dreamt he was know if he was Zhuangzi who had dreamt he was

a butterfly, or a butterfly dreaming he was a butterfly, or a butterfly dreaming he was

Zhuangzi. Zhuangzi.

Brain in a vat?Brain in a vat?