View
826
Download
4
Category
Tags:
Preview:
Citation preview
By Miguel Cortinas and Ryan Longo
Optical Illusions
Main Objective
• Explain the idea of optical illusions and their cause.
Introduction to Optical Illusions
• Optical Illusion- (visual illusion) caused by visually perceived images that differ from reality.
• The information gathered by the eye is processed in the brain to give a perception that does not match up with the physical measurement of the stimulus source.
• Three main types: Literal, Physiological, and Cognitive.
Literal Illusions
• Literal optical illusions are images that differ from the objects that create them.
• Artists may use objects such as fruit or foliage to create a portraiture or scenery.
Physiological Illusions
• Physiological illusions are the effects on the eyes and brain of excessive stimulation of a specific type.
• Artists may use color or movement to confuse the viewers' eyes and brains.
Cognitive Illusions• Cognitive illusions are
where the eye and brain make unconscious inferences.
• They can also be known as "mind games".
• Perspective and color heavily influence this genre.
Idea of Optical Illusions
• When we witness an illusion, we perceive something that does not correspond to what is actually out there—what exists in the real world.
• Illusions fool us! They convince us of things that are not true.
• Dictionary definitions of illusion usually state that an illusion is a sensory perception that causes a false or distorted impression, or a misrepresentation of a "real" sensory stimulus.
Illusions
• Illusion is a kind of wrong perception.
• In an illusion, an external stimulus is always present. In other words, illusions are caused by external stimulations.
• Illusions are almost universal.
• The same situation arouses the same type of illusion in most people.
Hallucinations
• Hallucination is a false perception.
• During hallucinations, no external stimulus is present. Hallucinations are caused by internal stimulations.
• A hallucination is seeing, hearing, tasting, smelling or feeling things that do not really exist.
• Certain drugs can cause hallucinations.
• Certain mental illnesses can cause hallucinations.
• People who have hallucinations are not necessarily ill.
• Lack of sleep can also cause hallucinations.
Don’t Believe Your Eyes• Illusions are misperceptions that are perceived by most
people, and are based on a specific stimulus received under certain conditions.
• Some experiments with animals indicate that several species of mammals and birds are "fooled" by illusions in much the same way we are.
• Illusions are different from both hallucinations and delusions.
ExamplesThis just looks like a normal triangle right? But where does it end?
At first look this cube looks fine, but look at the center stem.
Is It A Rabbit or A Duck??
Evaluation Questions
1. What is an optical illusion?
2. What are the causes of optical illusions?
3. What are the 3 types of illusions?
4. How do optical illusions differ from hallucinations and delusions?
Any Questions???
Bibliography• Block, J. (n.d.). What is an Illusion?.sandlotscience.com
. Retrieved October 29, 2013, from http://www.sandlotscience.com/EyeonIllusions/whatisanillusion.htm• Nierenberg, C. (n.d.). Optical Illusions: When Your Brain Can't
Believe Your Eyes. ABC News. Retrieved October 29, 2013, from http://abcnews.go.com/Health/EyeHealth/optical-illusions-eye-brain-agree/story?id=8455573• Nin, A. (n.d.). Causes of Optical Illusions.buzzle.com
. Retrieved October 29, 2013, from http://www.buzzle.com/articles/causes-of-optical-illusions.html
Recommended