Sensation and Perception Chapter 4 Sensation and Perception

Sensation and Perception Chapter 4

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Sensation and Perception Sensation- the process of receiving information from the environment n Perception- the process of organizing sensory information and making it meaningful n Absolute Threshold- the level of sensory stimulation needed for sensation (and thus perception) to occur n Ex. A dim light in a well light room is barely visible, yet highly visible in a dark room n Ex. Slight ding is barely audible in a noisy room, yet highly audible in a quiet room n

Sensation and Perception n Subliminal Perception (Subliminal Messages)stimulation that is below our threshold and takes place below our level of consciousness 100 Watch clips of movies n Percentage of correct detections 75 50 Does subliminal advertising work? n Subliminal stimuli 25 0 Low Absolute threshold Intensity of stimulus Medium

Sensation and Perception Weber’s Law- to perceive a difference between 2 stimuli, they must differ by constant proportion n Sensory Adaptation- diminished sensitivity with constant stimulation n Ex. Smell when you walk in a restaurant n Ex. Light in a movie theater n

Whorff Hypothesis n Show list of colors and label the colors n List as many words for “love” as you can List as many words for “snow” as you can n n Whorff Hypothesis- the more words a culture has for something, the more they perceive it n Ex. Teenagers can think of many words for love n Ex. Eskimos have many words– we have only a few

Sensation- Vision- sense of seeing White Light- light as it originates (off the sun or off a bulb) before it is broken into different frequencies

Vision cont

Vision cont Cornea- clear outer covering of the eye n Pupil- adjustable opening in the eye n black circle n Gets larger in darkness to allow more light in, and smaller in brightness to keep light out n Iris- colored circular muscle that opens and closes the pupil n Lens- behind pupil to change shape and focus the image in the retina n

Vision cont Retina- inner surface in the back of the eye which contain million of receptors n Rods- visual receptor for black and white n Cones- visual receptors for color n Page 95 in the book Fire Truck n Fovea- central part of the retina where cones exist and images are projected n Optic Nerve- carries visual information to the brain for interpretation n

Vision cont n Blind Spot- portion of the retina where the optic nerve exits the eye, and there are no rods and cones n Put hand over one eye, place other hand straight out at arms length and one finger up, move hand SLOWLY outward, finger will “disappear” n Page 94 in the book

Vision cont

n n Nearsightedness - see nearby objects more clearly Farsightednesssee faraway objects more clearly Color Blindness - inability to perceive certain colors such as red and green Color blind test page 96 Vision cont

Vision cont n Afterimage- image that remains after stimulation of the retina has ended n Cones not used fire to bring the visual system back in balance Another afterimage activity on page 97

Vision n Opponent Processing Theory- opposing retinal processes enable color vision Red – Green n Blue – Yellow n Black – White n

Sensation- Hearing Audition- sense of hearing n Pitch- how high or low a sound is n n Depends on the frequency- how many times the wave passes through a point Timbre- the complexity of a sound n Intensity- how loud a sound is n Decibels- measure of sounds intensity (loudness) n

Hearing cont

Hearing cont n Eardrum- piece of skin stretched tightly over the entrance to the ear n n Cochlea- snail shaped part of the ear filled with liquid and small hairs Cilia- hair cells in the cochlea that receive different frequencies n n Like a real drum Sound waves hit the ear drum and vibrate, causing connected bones to vibrate Like strings on a musical instrument Auditory Nerve- bundle of nerves that carry sound from the ear to the brain

Sensation- Touch n Cutaneous Receptors- nerve receptors in the skin which respond to pressure, temperature, and pain n 3 Sensations of touch: Pressure n Temperature n Pain n

Sensation- Smell Olfaction- the sense of smell n Olfactory bulbs- units that receive odor molecules and communicate their nature to the brain n Pheromones- odor chemicals that communicate a message n

Smell cont Olfactory nerve Olfactory bulb Nasal passage Receptor cells in olfactory membrane

Smell cont Number of correct answers Women and young adults have best sense of smell 4 Women 3 Men 2 0 10 -19 20 -29 30 -39 40 -49 50 -59 60 -69 Age Group 70 -79 80 -89 90 -99

Sensation- Taste n Taste Receptors- chemical receptors on the tongue that decode molecules of food or drink to identify them n 4 Sensations of Taste: Salt n Sweet n Sour n Bitter n

Sensations n Sensory Interaction- principle that one sense may influence another n Ex smell and taste regarding food