Sensation and Perception 4 Sensation and Perception

Sensation: Receiving Messages About the World Sensation and Perception Sensation: Receiving Messages About the World Sensation- the process of receiving, translating, and transmitting messages from the outside world to the brain. Sense organs- see, hear, taste, smell, touch, balance, and experience the world Sensory receptor cells transmit sensation

Translating Messages for the Brain Sensation and Perception Translating Messages for the Brain Transduction – translates one form of energy (incoming stimuli) into another (sensory information)

Sensory Limits: How Strong Must Messages Be? Sensation and Perception Sensory Limits: How Strong Must Messages Be? Threshold – lower limits Absolute threshold – smallest to be detected Difference threshold – smallest difference between 2 stimuli to be detected 50% of time Sensory adaptation – one’s sensitivity to a stimulus varies from time to time

Sensory Thresholds Vision Hearing Taste Smell Touch A candle flame seen at 30 mi. on a clear, dark night Vision The tick of a watch under quiet conditions at 20 ft. Hearing One teaspoon of sugar in 2 gallons of water Taste 1 drop of perfume diffused into the entire volume of a 3 room apartment Smell The wing of a bee falling on your cheek from a height of 1 cm Touch

Perception: Interpreting Sensory Messages Sensation and Perception Perception: Interpreting Sensory Messages Perception- the process of organizing and interpreting information received from the outside world. Visual Perceptual organization Figure-ground Similarity Continuity Closure Proximity

Laws of Perceptual Organization Figure-Ground

Laws of Perceptual Organization Law of Proximity Law of Continuity

Laws of Perceptual Organization Law of Similarity Law of Closure

Perception: Interpreting Sensory Messages Sensation and Perception Perception: Interpreting Sensory Messages Perceptual Constancy Brightness constancy Color constancy Size constancy Shape constancy

The retina has a two-dimensional surface. Sensation and Perception Depth Perception The retina has a two-dimensional surface. Monocular cues - perception with one eye Texture gradient Linear perspective Superposition Shadowing Speed of movement Aerial perspective Accommodation Vertical position

Depth Perception Binocular cues – perception with two eyes Convergence Sensation and Perception Depth Perception Binocular cues – perception with two eyes Convergence Retinal disparity

Visual Illusions p. 148-151 The Ponzo Illusion The Müller - Lyer Illusion Which line appears longer? Most think the top line is longer. The lines are of equal length.

Color Perception Perceived color based on the surrounding stimuli Page 151

Multisensory Integration Sensation and Perception Multisensory Integration Integrate and interpret information from multiple senses simultaneously Limited ability and accident occurrence Motivation, Emotion, and Perception Motivation and emotions influence perception Past experiences influence all perceptions