Sensation and Perception Sensation and Perception Sensation stimulation

Sensation and Perception

Sensation and Perception • Sensation: stimulation of sense organs • Perception: selection, organization, and interpretation of sensory input Five senses: Vision Hearing Touch Taste Smell

We do not view the world as it is, but instead actively construct a perception of it,

Vision - components Cornea: where light enters the eye Lens: focuses the light rays on the retina Iris: colored ring of muscle, constricts or dilates via amount of light Pupil: regulates amount of light Cones: adapted for color vision, daytime light, and detailed vision Rods: adapted for vision in dim light

Vision - color

Figure 4. 12 Vision - color A replica of the Ishihara test for color blindness.

Figure 4. 9 Vision - color Negative afterimages. Stare at the dot near the middle of the flag for at least 30 seconds. Then look immediately at a plain sheet of white paper or a white wall. You will see the American flag in red, white, and blue. Reduced sensitivity to green, black, and yellow in the visual system, caused by prolonged staring, produces the complementary colors.

Vision - color Brightness Constancy. The orange squares within the blue squares are the same hue, yet the orange within the dark blue square is perceived as brighter. Why?

Vision - Acuity

Vision – Gestalt principles

Vision – Reversible Figures

Vision – Perceptual Set

Vision – Subjective Contours

Vision – Subjective Contours

Vision – Distal and Proximal Stimuli

Vision – Perceptual illusions

Vision – Perceptual illusions

Vision – Size and Distance The trade-off between size and distance: A given image on the retina can indicate either a small, close object or a large, distant object.

Vision – Attention One of the drawings used by Mackworth and Loftus (1978) to investigate attention. Observers attend to unexpected objects longer than they do to expected objects. In this drawing, observers looked longer at the octopus than they did at a tractor placed in the same spot. What do you think would happen if a tractor were shown upside down or on the roof of the barn?

Vision – Depth

Vision - Depth

Vision - Movement

More examples on the internet… • Left-handed v. Right-handed quiz http: //www. illusions. 1570 films. com/ • Illusions - many examples http: //www. scientificpsychic. com/graphics/ • I still can’t figure this out! http: //www. tommcmahon. net/2003/12/12_then_13_guys. html

(2) Hearing - components

Hearing – source and loudness

(3) Touch - Components

(4) Taste - Components Figure 4. 49 The tongue and taste

(5) Smell - Components