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Del curso dictado por Duke University

Visual Perception and the Brain

140 calificaciones

Duke University

Visual Perception and the Brain

140 calificaciones

Learners will be introduced to the problems that vision faces, using perception as a guide. The course will consider how what we see is generated by the visual system, what the central problem for vision is, and what visual perception indicates about how the brain works. The evidence will be drawn from neuroscience, psychology, the history of vision science and what philosophy has contributed. Although the discussions will be informed by visual system anatomy and physiology, the focus is on perception. We see the physical world in a strange way, and goal is to understand why.

De la lección

Seeing Lightness, Darkness and Color

Definitions2:54

Light and Color8:20

How the Retina Initiates Color Vision (part 1)9:53

How the Retina Initiates Color Vision (part 2)7:26

Why Do We Have Color Vision?3:26

Describing Color Perception12:26

The Strange Way We See Color10:43

An Empirical Answer (part 1)7:23

An Empirical Answer (part 2)4:41

Topic Summary3:12

Module Summary0:24

Conoce a los instructores

Dale Purves
M.D.
Duke Institute for Brain Sciences

In this topic, we're going to talk about color.

And color vision has been of tremendous interest to everybody.

An interest that far outweighs its biological importance.

A lot of animals don't have color vision.

As we'll see in people who are color deficient or

color blind don't have that much of a problem getting along in the world.

But color, as I said, is fascinating and all the natural philosophers from

Isaac Newton to Thomas Young to Helmont and James Clerk Maxwell, we'll talk about

these people as we go along, have been interested in color vision and

as I say their devotion to it has outweighed it's biological importance.

But it does say something very important about vision, of course,

and anyone who wants to explain vision needs to explain color vision.

As well as the black and white vision that we talked about in the previous topic.

So let me begin with some definitions.

First of all, what is color?

Color is a set of perceptions that

are elicited by the spectral distribution of light.

What does that mean?

Well before, when we talked about luminance, we talked about the totality of

the energy that was falling on a detector, the photometer, or the retina.

And now we're going to talk about the distribution of that energy because that's

the basis for color vision.

So, as you know and as we'll talk about in a minute

Light has a variety of wavelengths and the distribution of wavelengths in

any stimulus that is coming to your retina can be described in terms of a spectrum,

the distribution across the range that we are able to see, 400 to 700 nanometers.

The energy distribution across that range is the basis of color vision.

There is of course a way of making physical measurements

of the relative intensities of wave lengths measured by a spectrophotometer.

A spectrophotometer is just a photometer.

It is not too complicated an instrument, but

an instrument that is made for the purpose of determining

the distribution of energy across that bandwidth.

This corresponds the physical measurement of

color in terms of wavelength energy or energy of different wavelengths

as we said before has a corresponding psychophysical measurement.

And that measurement has to be reported.

And it's the color that's reported by a normal subject, typically made, and

we'll go into this in a few minutes, typically made by comparison.

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