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Objectives. Identify the sensesDefine sensation and perception Describe the structure of the eye and the mechanism of seeing and perceptionExplain the theory behind magic eye pictures.. Sensation. We have all heard about our senses. Have we? How many senses do we have.Write down as many sense
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1. Sensation and Perception
2. Objectives Identify the senses
Define sensation and perception
Describe the structure of the eye and the mechanism of seeing and perception
Explain the theory behind magic eye pictures.
3. Sensation We have all heard about our senses.
Have we? How many senses do we have.
Write down as many senses as you can think of
4. How many senses? Most people stop at FIVE
Vision, Hearing, Touch, Taste, Smell
Current thinking includes another sense
Kinesthaesia a sense of balance or position.
5. The Sixth Sense? Psychologists study the possible existence of a paranormal sense
At the moment, it is considered uncertain.
At Edinburgh University, the Centre for Parapsychology collects reports from all over the world and investigates them. A bit like Scully and Mulder but in real life.
6. The Sixth Sense Edinburgh have found that all but about 0.1% could be explained by existing theory.
A very high proportion were shown to be fraudulent.
The 0.1% remaining
Edinburgh say they cant be explained
YET!
7. Visual Perception Sensation: the physical stimulation of the sensory receptors
Perception: the process of interpreting and understanding sensory information
What happens when sensation and perception go wrong?
8. Breakdown in perception and sensation Anaesthetic e.g. Epidural during childbirth
Sensory stimulation is definitely taking place, but no perception of pain.
Schizophrenia e.g. auditory illusions
The voices are real enough, but sensory stimulation is not taking place.
10. The Retina Consists of nerve endings
Rods named because of their shape are most sensitive but only black & white
Cones sensitive to colour
11. The Blind Spot Test for your blind spot using the handout.
The explanation is that our mind tries to fill in the missing field of vision caused by the blind spot. It makes the best guess, based on the background.
But it may be disastrous.
14. Three Dimensions The image on the retina is in two dimensions (just like a photograph)
And yet we see in three dimensions we do exist in a solid world after all!
How can we perceive distance and dimensions?
15. Convergence Try the pencil test
Focus on the pencil and as you move it towards you still in focus, you should feel the muscles in your eye protesting!!
By storing the muscular position for focus at a particular distance, the mind can determine the distance of an object.
18. Retinal Disparity Another pencil test. Hold the pencil in front of you.
Close one eye, open it, then close the other.
What do you notice?
19. Disparity You get two views of the pencil
Just as you get two views of the man in the picture
20. 3D perception If we can superimpose the images from each eye, our mind will smooth off the image and what we see will appear in three dimensions.
21. Stereoscopic vision This is the principle behind the stereoscope
22. And also behind Magic Eye Pictures