250 likes | 332 Views
Delve into the intricacies of sensation and perception as the brain deciphers sensory information through detection, interpretation, and adaptation. Explore ambiguous figures, sensory overload, JND, and Weber's Law.
E N D
Sensation and Perception Chapter 4
Defining Sensation and Perception • Sensation • The detection of physical energy emitted or reflected by physical objects. • It occurs when energy in the external environment or the body stimulates receptors in the sense organs. • Perception • The process by which the brain organizes and interprets sensory information.
Ambiguous Figure • Colored surface can be either the outside front surface or the inside back surface • Cannot simultaneously be both • Brain can interpret the ambiguous cues two different ways
The Riddle of Separate Sensations • Sense receptors • Specialized cells that convert physical energy in the environment or the body to electrical energy that can be transmitted as nerve impulses to the brain.
Sensory Overload • Overstimulation of the senses. • Let’s play an observation game! • Can use selective attention to reduce sensory overload. • Selective attention • The focusing of attention on selected aspects of the environment and the blocking out of others. • Inattentional blindness
Measuring Senses • Absolute threshold • Difference threshold • Signal-detection theory
Absolute Threshold • The smallest quantity of physical energy that can be reliably detected by an observer.
Absolute Sensory Thresholds • Vision: • A single candle flame from 30 miles on a dark, clear night • Hearing: • The tick of a watch from 20 feet in total quiet • Smell: • 1 drop of perfume in a 6-room apartment • Touch: • The wing of a bee on your cheek, dropped from 1 cm • Taste: • 1 tsp. Sugar in 2 gal. water
Pledge of Allegiance • I pledge allegiance
JND • Each slide of the Pledge of Allegiance increased the font size. • Did you notice?
Just Noticeable Difference (JND): The smallest amount of change in a stimulus that can be detected half the time. Stimulus Discrimination
Weber’s Law • JND is proportional to the magnitude of the stimulus • The larger the stimulus the larger the change must be to be noticed!!
For a difference to be perceptible, 2 stimuli must differ by a constant proportion, not amount Light: 8% Weight 2% Tone: .3% Weber’s Law:
Backmasking!! • Secret messages hidden in musical lyrics? • Let’s find out!! • Jeffmilner.com
Signal-Detection Theory • A psychophysical theory that divides the detection of a sensory signal into a sensory process and a decision process. (expectations, experience, anticipation)
Sensory Adaptation and Deprivation • Adaptation • The reduction or disappearance of sensory responsiveness when stimulation is unchanging or repetitious. • Prevents us from having to continuously respond to unimportant information. • Deprivation • The absence of normal levels of sensory stimulation.