Background: What We Actually See

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来自 Duke University 的课程

Visual Perception and the Brain

129 个评分

Duke University

Visual Perception and the Brain

129 个评分

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.

从本节课中

Background

Background: What We Actually See3:03

The Strange Way We See the Physical World (part 1)8:11

The Strange Way We See the Physical World (part 2)7:05

The Inverse Problem7:36

Summary of Topic One2:02

与讲师见面

Dale Purves
M.D.
Duke Institute for Brain Sciences

So in this first module we're going to be talking about things that we need

as a background for the course.

I'm going to begin by trying to get you involved

in the mysteries of vision, by telling you

a little bit about what we actually see and describing the peculiarities of that.

So let's begin with some basic definitions,

and the first one is perception.

I already said perception is what we are aware of, so

that's about as good as it gets.

If you want to define perception in terms of vision,

it's what when we look out at the world, we're actually aware of seeing.

And you might ask well, what about you're not focused on that, and

you're seeing stuff but you're not really aware of it?

Yeah that's true.

And the same kinds of mechanisms and strategies apply,

but basically when we're talking about perception, we're talking about what we

see and, generally speaking, we're aware of what we see.

Or at least we can be.

That's very different than physical measurements.

So you can make physical measurements of the world that's out

there with instruments.

They can be simple, they can be complex.

You can use a ruler, a protractor,

something like the photometers in your smart phones.

Or much more complicated instruments but basically these are physical measurements

that physicists and business scientists have been making for a long, long time.

That's quite distinct from psychophysical measurements, measuring

what we actually see and there is really no way because that is subjective.

Physical measurements, of course, objective, but what we see is subjective.

There's no real way of measuring that in the same sense.

But, nonetheless,

it can be made with measurements that are comparative measurements.

So, this is a strategy that was undertaken first in the 19th century

by German vision scientists and psychologist of that era.

And basically you can understand what you're seeing and measure it in

a very good way, but not in the same objective way that we measure angles and

line lengths, and so on, you can do that by making comparative measurements.

You take a standard stimulus and

you ask somebody to adjust another stimulus until the two match.

And in those kinds of ways and there are different ways of doing that.

We'll talk about some of them as we go along.

In that way you can make psychophysical measurements that are pretty useful.

But they're not the same as physical measurements and

you need to understand that.

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