1 Sensation and Perception

2 What is Sensation?? There are sense receptors for smell, temperature, vision, hearing, and taste When the sense receptors detect an appropriate stimulus they convert the energy of the stimulus into electrical impulses that travel through neurons to the brain.

3 What is Perception? It is a set of mental operations that gives organization changes the sensory impulses into meaningful patterns.

4 What are the receptor cells for each of the Senses? Vision- Rods and cones in the eye Hearing-The hair cells in the inner ear. Smell-The receptor cells in the nose. Taste-The taste buds in the tongue. Touch-Nerve endings in the skin.

5 Absolute Thresholds Defined as the weakest amount of stimuli that can be sensed. Vision-A candle flame viewed from 30 miles on a dark night Hearing-The ticking of a watch 20 feet away. Smell-One drop of perfume in a small house. Taste-One teaspoon of sugar dissolved in 2 gallons of water. Touch-The wing of a fly falling on a cheek.

6 Difference Thresholds? Defined as The minimum amount of difference that can be detected between two stimuli.

7 The Structure of the EYE

8 Eye See You!! PartFunction A. LensInside the Iris that changes in shape to focus on objects B. IrisThe colored part of the eye that dilates and constricts according to the available light C. CorneaThe front surface of the eyeball that bends light rays D. RetinaA layer of tissue in the back of the eye that contains the rods and cones. Images are projected onto the retina E. Optic NerveComposed of ganglion cells that leave the eye and go to the brain F. Blind SpotThere are no rods and cones where the optic nerve leaves the eye and, thus, no vision G. FoveaA small area of the retina that has the sharpest and clearest vision because of the largest concentration of rods and cones.

9 What are the properties of Rods and Cones? RodsCones Type of Vision Black & White Color Light conditions Dimly LitWell lighted DistributionNot on fovea On fovea scattered on retina

10 Related Terms Afterimage –Is a color’s complimentary color The Blind Spot –The point where the optic nerve leaves the eye and where there is no vision.

11 The Structure of the Ear

12 Structure of the Ear PartFunction A. Ear DrumTissue that vibrates in response to sound waves and transmits sound waves to middle the middle ear B. Malleus (hammer)Vibrations cause the Malleus to vibrate Incus. C. Incus (anvil)The vibrations cause the Incus to vibrate the Stapes D. Stapes (stirrup)The Stapes vibrates the oval window E. Oval WindowThe oval window connects the middle ear to the cochlea. F. CochleaVibrations from the oval window causes motion to the fluid inside the cochlea G. Semi-circular CanalsInvolved in the sensing of movement of the body H. Auditory NerveCarries impulses from the ear to the brain

13 The Structure of the Tongue The sense of taste or gustation is activated by receptors called taste buds. Each bud has approximately 50 receptor cells. The basic tastes are sweet, sour, salty, and bitter. In some cultures, umami is considered to be a sixth taste. It is the taste of monosodium glutamate. Flavor is an interaction between taste and smell.

14 Perception Influences would include… –Bottom-Up Processing Small components are combined until a complete perception is formed. –Top-Down Processing Past experiences and knowledge are used to recognize the and identify the simpler elements of the whole figure. –Perceptual set An expectation of what will be perceived.

15 Gestalt Organizing Principles Figure-ground Similarity Proximity Continuity Closure

16 Perceptual Constancies Shape Constancy Size Constancy Brightness Constancy

17 Is it me or is this hallway getting smaller???? What is that light? We’ll have to bend down to get out!!

18 Is Mr. Matiya bigger than Mr. Wooley?

19 Right before your eyes!! Mr. Wooley is growing!!

20 Mr. Geiger? How small is Mr. Wooley?

21 How BIG are we?? In Real- Life?

22 Depth Perception The ability to see the world in three dimensions Binocular Depth cues such as convergence and binocular disparity

23 Depth Perception Monocular Perception –Interposition –Linear perspective –Relative Size –Texture Gradient –Shadows and shading –Motion parallax

24 Hall of Illusions The Devil’s pitchfork! Here doggie, come here

25 Hall of Illusions Triangles or…a cube?

26 Hall of Illusions Let me count using my fingers, that’s 1, 2,3, 4, 5, 6, 7, 8!!!! What cube?

27 Hall of Illusions Do not stare at the dot. I warned you!!!!

28 Hall of Illusions Why is it called an impossible triangle??? Jesus ?

29 Hall of Illusions Young lady or old lady? Are you, a Man or a Mouse?

30 Hall of Illusions Tree or wolf? Question mark or bird?

31 Hall of Illusions

32 The Impossible Triangle

33 An illusion or do we see what we want to see?? A hidden picture in the lettering of Coca-Cola of a man doing cocaine?

34 Hall of Illusions…The End