Front page: Front page The brain: What is visual perception?
“visual perception is the end product of vision”
It can be described as the way the brain interprets what the eyes see.
The brain An Introduction to Visual Perception! The brain: THE BRAIN
The brain receives information from the retina, then using a hierarchical method processes this information using different parts of the brain e.g. lateral geniculate nucleus and the primary and secondary visual cortex of the brain.
The main problem with visual perception is that it is not simply a translation of the image seen by the retina, making it difficult for scientists to explain what we actually see. The brain Slide4: This can be altered by previous experiences.
The Chairs theory
It can effect the way you see a situation.
The Taxi theory
It is used in media to make you have the opinion of someone that they want you to have.
The Bad guys/good guys theory Slide5: Human Vision Human vision is not the only way the world is seen,
Animals see the world in different ways.
some animals don’t even see the world but rely on other senses e.g. bats and dolphins
Flies have what’s known as composite eyes, a TV run at 25 frames per second but to a fly this is very slow.
birds such as hawks can see up to 8 times further than a human. The range of distance is measured in dioptres, a child’s is 14, an old persons is 1, however a diving bird’s vision is 50 dioptres.
field of vision also is limited on a human to between 160-240, where as a hare’s field of vision is 360.
Different creatures vary the amount of brain is dedicated to vision, the octopus dedicates 50% to sight but we still don’t know how other creatures make sense of what there eyes see. No single creature can see all what others can. We forget that the human world of vision is only one such world.
Slide6: Homo significans The world is seen in different ways by different creatures, as humans we put a large emphasis on visuals. We do not always believe our eyes, we know that a pencil in a glass jar will look bent and that a moon closer to the horizon will appear bigger and that there are such things as optical illusions.
Humans as a species are driven by a desire to find meaning. This relates to the title, because as humans we are all “homo significans”- meaning makers.
This is proved with a few simple shapes and lines, that the mind strives to find meaning in.
What do you see here:
Your more likely to see five pairs close together than 4 pairs more spaced with a line either side spare. We do this because the brain puts the closer objects together. herman: Hermann Von Helmholtz, seen as the founder of visual perception studies believed vision was a form of unconscious inference, (Inference is the act or process of deriving a conclusion based solely on what one already knows)
Two well known assumptions are that light comes from above and that objects are viewed from above, not below.
Visual illusions are where this process goes wrong e.g…
Hermann Von Helmholtz herman The Scintillating grid illusion: The Scintillating grid illusion Black spots will seem to appear very quickly at the intersections. Optical illusion: Optical illusion Focus on the black dot and move your head back and forth
This creates the illusion that two circles are moving Gestalt Theory: Gestalt Theory The Gestalt Theory originally came about in the 1890’s.
Gestalt is German for “Shape/Form/Likeness”
There are 3 main Gestalt psychologists:
Max Wertheimer (Is credited as the founder of the movement of Gestalt Psychology)
The concept of Gestalts Psychology was originally foundered by an Austrian psychologist called Christian Freiherr von Ehrenfels
The major problem with the Gestalt laws and principles are that they are mainly descriptive and not explanatory. Gestalt Theory: Gestalt Theory
The Gestalt Principles can be split into 3 groups:
Figure and Ground
Similarity, Proximity, Common Fate and Good Continuity
Closure, Area and Symmetry
Gestalt Theory: Gestalt Theory
Figure and Ground explains how we put different elements
together to make one scene or a whole image.
“Figure” is the more dominant shape.
“Ground” can be referred to as the Background.
What do you see this image as?
A Goblet on a Black background
A Black Silhouetted Profile on a White background.
Once you have identified the figure, the rest of the
image becomes the ground.
Camouflage is most likely a breakdown in the figure ground perception. When the dominant shape is so much like the ground it
disappears from view.
Can you spot the bird?
FIGURE AND GROUND The most famous “Figure and Ground” image is the one by the Danish psychologist Edgar Rubin.
Gestalt Theory: Gestalt Theory When we have similar objects of size, shape and colour again we form groups.
This image is grouped together Squares and Circles
by colours SIMILARITY Gestalt Theory: Gestalt Theory When objects which are closer to each other we tend to associate them together to form groups.
You will see columns rather than You will see rows rather than rows columns
Real life example. MTV Music awards.
We group this image into 2 parts, the top left this shows us this is the MTV music awards, and the bottom right which groups together the sponsors of the awards. PROXIMITY Gestalt Theory: Gestalt Theory Objects which are facing the same direction or appear to be travelling in the same direction are usually grouped together.
The arrows which are pointing in a Again the lines facing upwards tend
common direction are usually grouped to be grouped together.
COMMON FATE Gestalt Theory: Gestalt Theory Seeing things as a whole is important however seeing in a whole is not necessarily what we are meant to see.
What do you see here?
CONTINUITY Gestalt Theory: Gestalt Theory Seeing things as a whole is important however seeing in a whole is not necessarily what we are meant to see.
What do you see here?
Well there are two answers.
Continuity makes us see 2 lines crossing
Is it actually 4 lines, A-O, O-D, C-O and O-B
CONTINUITY Gestalt Theory: Gestalt Theory If we have a large pattern with missing components we tend to fill in the missing parts to create the image we actually see.
When joined you can see a triangle.
This image can be seen as an “S” shape
Looking at this object we tend to form a 3D sphere.
If you look closely this image looks like the snake.
These two images can be closed
together to form a circle and a square.
Real Life example. WWF Logo / IBM Logo
This image can be closed
This image creates the to make a panda
illusion of 3 letters, I, B and M
CLOSURE Gestalt Theory: Gestalt Theory This principle shows us that when areas are overlapping, the smallest area is seen as the figure and the larger is the ground. When we look at this object, we see this as one object on top of the another instead of a hole in the larger area.
We can reverse this perception by adding shading.
On a black larger object we now see is hole.
AREA Gestalt Theory: Gestalt Theory
Objects which are symmetrical, we are more likely to group
This principle also describes looking at an image and perceiving it as a
whole figure instead of it’s individual parts.
What do you see here?
2 Overlapping diamonds
2 Large diamonds and 1 small diamond
2 L-Shapes and 1 diamonds
If you are viewing this according to the principle you are
Most likely viewing this as 2 overlapping diamonds. SYMMETRY Gestalt Views In Psychology: Gestalt Views In Psychology Conclusion: Conclusion Any Questions?: Any Questions? Watch the black cross
To see the green circle