This course deals with an Introduction to Psychology as a Science. Psychology is the study of behavior and the mind. But all of us have tried to understand and predict behavior throughout our lives, first with our parents, then with our peers and teachers, and finally with our friends and co-workers. The difference is that psychological scientists conduct research that discovers the facts about behavior and our minds, so its principles are based on science and not just on intuition and experience. The course covers all areas of Psychology, discussing scientific findings relevant to each area. The content of the course has received approval from "Quality Matters", an organization that evaluates on-line courses. The learning outcomes are: (1) Students will be able to recognize and describe major psychological principles, theories and perspectives; (2) Students will be able to distinguish between different methods used by psychological scientists to study the different areas of psychology; (3) Students will be able to describe the "nature-nurture" controversy across different areas of psychology; (4) Students will know that the basic principles of psychology are based on sound research; and (5) Students will know how the nervous system and other biological systems are involved in understanding behavior and the mind.
Lecture Video 4.5: Depth Perception
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Section 4: Sensation and Perception
Information from the environment is translated by our senses into neural energy. This information is then interpreted by the brain (perception).
教學方
Dr. Anderson D. Smith
Regents’ Professor Emeritus
[BLANK_AUDIO].
Anderson Smith again. Today, we're going to talk about depth
perception. How we use vision to tell us how far away
something is from us. When we deal with visual perception,
we're really dealing with various kinds of qualities.
For example, we can tell, for, we could detect forms, detect objects by being
able to tell where the edges and borders of things are, we could detect color,
color vision and we also can perceive depth, how far away something is.
There are two kinds of depth perception cues, they're binocular cues where we,
use both, get feedback from both eyes. Then monocular cues, which don't require
both eyes, and we can get information from just one eye.
First are binocular cues, they are three kinds of feedback coming to the brain.
One is retinal disparity. The fact that our two eyes are separated
from each other and as we stare at something, we have two images slightly
apart from each other because the eyes are separated.
This is the, at the, the binocular cues that shoots for 3D movies for example
like they have two cameras, separated by the same distance as your two eyes are,
they take pictures with those two cameras, and then by using glasses, of
different types, then they can fix it so you only see the information in the left,
from the left camera in your left eye, and information from the right camera in
your right eye. So you have retinal disparity and things
look in three dimensions rather than two dimensions.
When I was a child I had something called lazy eye, when one of my eyes would sort
of drift off, and I, I would just be using one eye, which isn't good.
And so, they developed this treatment where I put a polaroid screen on the
front of my television set, and I wore polaroid glasses so that with my left eye
I could only see the left side of the television set.
My right eye can only see the right side of the television set.
And so when my eye drifted off, I could only actually see one side, and that was
supposed to treat and keep me from doing that.
It didn't work, I had surgery when I was a kid and they fooled with the muscles so
that I use both eyes now. So I have better depth perception.
There's also feedback from accommodation. That is, as information comes into the
eyes, the lenses change their shape to focus the information on the back of the
retina. And, if feedback from those muscles that
control the lens actually provides us information as to how far something is
from us, how much change did they have to make with the lenses.
And then there's Convergence, and that's as something is closer to my two eyes, to
focus on it would have to move converge closer to the object.
If it moves away from me, it will separate, unless I can use the feedback
from those muscles controlling the direction the eyes are pointing to give
me information about how far something is away.
But we also have Monocular cues. these are cues in the environment that we
don't really need to have muscle feedback or to eyes to, to detect how far
something is away. The first is position, or relative
height, and that idea is that if something is at the top of a visual field
it tends to be further away than if it's close top us at the bottom of the visual
field. So things at the top are higher tends to
be seen as further away. We also have Relative motion.
that is that is something is close or far away from us it tends to move differently
as we're moving. For example, if you're looking at the
window of the car, hopefully when you're the passenger and not the driver, and
you're looking at the side window you notice that things far away from you tend
to be moving with you. With things that are really close like
the side of the road tend to be going in the opposite directions.
Relative motion tends to give us information about how far something is
away. Also Relative size, if you have two
retinal stimulation that are exactly the same, but one is seen as being further
away it's going to be bigger. Than the one, because if it's further
away, it's causing the same sensation on my retina, it must be bigger, relative
size. Linear perspective is the fact that if
you have parallel lines going the distance they become closer together.
That's Linear perspecitve. Then there's Interpostition, the fact
that if an object is closer to me it's going to be in front of the an object
that's further away. So, if I bring it closer to me, it
actually, or take it further away, it will be seen as behind something,
interposition. And then finally, not finally, Light and
Shadow, we can use the Light and Shadow so that where the shadow is to tell us
where something is far away or close to us.
And then Aerial persepective. Things that are further away tend to be
seen as hazy, hazier than things that are close to us.
If you look at a mountain scene, the mountains that are further away are the
ones that are have the most haziness. Ones that are close by are clearer.
And we use all of these sort of cues, learned cues, to help us detect depth.
Now, here's an example at, of two of those monocular cues.
One is, linear perspective. The fact that the two railroad tracks are
obviously parallel, but as they go into the distance.
They converge, they become closer together, linear perspective.
And because of that, because of perceiving the railroad track where the
white bar is, is further away than the gold bar.
Even though they have exactly the same sensation, same stimulation of the
retina, its seen as bigger because it's clearly further away.
So, I can move that gold bar, which I've put on top.
And you can see they are exactly the same size, even though the one at the top is
seen as further away. Depth perception is one of those innate
characteristics that we have. And this was actually demonstrated by
Eleanor Gibson. With our apparatus, which is called a
Visual Cliff, and excuse my poor drawing of it.
But you place the infant on the checkered top of this, even though it has a glass
payne, plain that goes all the way across.
So this, the part that's clear with the, with the checkered drawing at the bottom
of the cliff. It's safe because it's, it's a glass
paint going across both sides. But if you put the infant on the, on the
checkered side and the mother stands at the far side and says, come on, come
here, the child will want to see the mother.
The interesting thing is it will not cross the Visual Cliff.
It will, it'll move away from Visual Cliff, it will cry if it wants to see the
mom. But it will not wander out into the
Visual Cliff. By the way, this is true all animals too,
you can have a goat, a lamb that's just a few days old, but is able to stand up,
and it won't go over to the Visual Cliff. So, there does seem to be an ina, innate
fear of heights or ability to detect depth.
but as we grow older. it becomes much more complex as we learn
all these other cues. It makes Depth Perception more complex
than just this sort of fear of falling off the cliff.
Anyway, that's Depth Perception. Thank you.
