Mr. Silimperi Council Rock High School South Chapter 5 Sensation Sensation II

Transcription

1 Mr. Silimperi Council Rock High School South AP Psychology Name: Date: Chapter 5 Sensation Sensation II Psychophysics study of the relationship between physical characteristics of stimuli and our psychological experience of them Light- brightness Sound- volume Pressure- weight Taste- sweetness 1. Absolute Threshold minimum stimulation needed to detect a particular stimulus 50% of the time Absolute Threshold Intensity No No No Yes Observer s Response Detected Yes Tell when you (the observer) detect the light.

2 2. Difference Threshold minimum difference between two stimuli required for detection 50% of the time just noticeable difference (JND) Difference Threshold No No Yes Observer s Response Tell when you (observer) detect a difference in the light. 3. Signal Detection Theory a. predicts how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise) i. Penny Saved simulation b. assumes that there is no single absolute threshold c. detection depends partly on person s i. experience ii. expectations iii. motivation iv. level of fatigue v. ie. HOW SOON WOULD YOU NOTICE A RADAR BLIP OF AN APPROACHING SHIP? Percentage of correct detections Subliminal stimuli Subliminal When stimuli are below one s absolute threshold for conscious awareness 0 Low Absolute threshold Medium Intensity of stimulus

3 4. Weber s Law- to perceive as different, two stimuli must differ by a constant minimum percentage a. light intensity- 8% b. weight- 2% c. tone frequency- 0.3% 5. Sensory adaptation- diminished sensitivity as a consequence of constant stimulation GEE, THIS WATER IS cold! COMON IN. THE WATER IS FINE! 1. Transduction conversion of one form of energy to another in sensation, transforming of stimulus energies into neural impulses 2. Wavelength the distance from the peak of one wave to the peak of the next 3. Hue dimension of color determined by wavelength of light 4. Intensity amount of energy in a wave determined by amplitude brightness loudness Short wavelength=high frequency (bluish colors, high-pitched Great amplitude (bright colors, loud Long wavelength=low frequency (reddish colors, low-pitched Small amplitude (dull colors, soft

4 SPECTRUEM OF ELECTROMAGNETIC ENERGY This spectrum ranges from gamma rays as shorts as the diameter of an atom to radio waves over a mile long. The narrow band of wavelengths visible to the human eye (shown enlarged) extends from the shorter waves of blue-violet light to the longer waves of red light.

5 Mr. Silimperi Council Rock High School Sensation and Perception Name: Date: Eye Anatomy Part Cornea Function Pupil Iris Lens Retina Fovea Optic Nerve Rods Cones Blind Spot

6 1. Accommodation- the process by which the eye s lens changes shape to help focus near or far objects on the retina 2. Acuity- the sharpness of vision 3. Nearsightedness- condition in which nearby objects are seen more clearly than distant objects because distant objects in front of retina 4. Farsightedness- condition in which faraway objects are seen more clearly than near objects because the image of near objects is focused behind retina normal nearsighted farsighted vision vision vision Location in retina peripheral retina near center of retina Color sensative detect black, white and gray; NO fine detail and color vision; YES Color sensitivity in low dim light? twilight or low light HIGH daylight or well-lit conditions; LOW # 120 million 6 Million

7 Mr. Silimperi Name: Council Rock High School South Date: AP Psychology Chapter 5 Sensation Vision pgs As feature detection cells are working separately and simultaneously the brain s higherlevel cells respond to combined information from those same cells. parallel processing Finally the brain recognizes and matches the constructed image with previously stored information / images and past experiences (assumptions, interests, and expectations) and thus identifies the stimulus (seeing Cartman). = conscious perception of the person you know! I see Cartman. HOW? Light rays reflect off him and travel into my eyes. The rods and cones, bipolar cells and ganglion cells convert the light waves energy into neural impulses. The brain receives the impulses and goes through FEATURE DETECTION(Hubel & Weisel) = brain responds to visual input Color Depth Movement Form Bars Edges Gradients of light

8 1. Trichromatic (three color) Theory Young and Helmholtz three different retinal color receptors red green blue Additive color mixing People who suffer red-green blindness have trouble perceiving the number within the design 2. Opponent-Process Theory- opposing retinal processes enable color vision ON OFF red green Afterimage effect green red Pg. 187 blue yellow yellow blue black white white black 3. Color Constancy Perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object My red mustang is red in my garage with no lights on, and red in the driveway as well with the sun shining on it!