Sensation and Perception Optical Illusions OPTICAL ILLUSIONS ILLUSIONS

Sensation and Perception: Optical Illusions

OPTICAL ILLUSIONS. . .

ILLUSIONS AND PERCEPTION • ILLUSIONS DEPEND ON PERCEPTION • PERCEPTION HAS THREE LINKS

THREE LINKS TO PERCEPTION EXTERNAL / PHYSICAL VISUAL APARATUS INTERPRETATION OF STIMULUS

WHAT IS AN OPTICAL ILLUSION ? • illusions that deceive the human visual system into perceiving something that is not present or incorrectly perceiving what is present. 10/21/2021 5

TWO TYPES • PHYSIOLOGICAL ILLUSIONS • COGNITIVE VISUAL ILLUSIONS 10/21/2021 6

1. A PHYSIOLOGICAL ILLUSION • is the what happens to the eyes as a result of prolonged stimulation. i. e. brightness, tilt, movement, color etc. • repetitive stimulation misleads the visual system in the early stages of visual processing.

2. A COGNITIVE VISUAL ILLUSION • Exploits the predictive cues of early visual processing. • Misdirects in-built assumptions or knowledge while processing.

OPTICAL ILLUSIONS WORK BY EXPLOITING VISUAL CUES 1. 2. 3. 4. 5. Texture Gradient Relative Motion of the picture Linear Perspective Light and Shadow Relative Size and Dimension

OPTICAL ILLUSION 1 This is the Bunny/Duck illusion. At first glance, what do you see? Now give it some time, but do not focus on one certain area, and then ask Yourself; what do I really see? Now, look again. You might be surprised!!!!!!

OPTICAL ILLUSION 2 Do you see some squares or rectangles? Really, this is nothing more than a bunch of lines going in every which direction, but the way our mind interprets these lines are totally different!!

OPTICAL ILLUSION 3 This is probably the most famous illusion of all time! Almost everyone has seen it! What do you see at your first glance of this illusion! Do you see an old lady, or do you see a young women? They are both there!!

OPTICAL ILLUSION 5 This is probably one of the hardest illusions that I have ever seen. When you first look at this, do you see and old man with ivy leaves around him, or do you see a couple kissing? Be patient and give it some time!! You will eventually see it

OPTICAL ILLUSION 6 Do the sides of the square appear to be bent in? Wait, now that is Impossible! Believe it or not, they are as straight as they come. If you do not believe me, take a straight edge and see for yourself!!!

OPTICAL ILLUSION 7 How many ways can you view this cube? Is the blue side outside the box or is it inside? Is it on the back of the box of is it on the side? Examine this cube closely, and let the light blue side guide you!

OPTICAL ILLSUION 8 At first glance, what do you see--Could it be the word "liar" or is it something more. I would definitely give this one a second look!

OPTICAL ILLUSION 9 When you look at this, you probably see a triangle. There is not one there! The way the circle parts are cut out, make us think there is a triangle there even though there isn’t any!

OPTICAL ILLUSION 10 Are the diagonals parallel? You bet they are!

OPTICAL ILLUSION 11 I have heard this illusion called the dancing elephant and several other things. I want you to look at the elephants feet and legs. How many are actually there?

OPTICAL ILLUSION 12 Is this man playing a sax, or is there something more here?

OPTICAL ILLUSION 13 • When you read this, what does it say? • A Bird In The Bush? • If you read this more carefully you will find that it says A Bird In The Bush!!!

Stare at the black lightbulb for at least 30 seconds. Then immediately stare at a white area on the screen or at a sheet of paper. You should see a glowing light bulb!

THE END……DNE EHT