PSYCH 7A Chapter Notes - Chapter 4: Occipital Lobe, Color Vision, Cerebral Cortex
Sensation and Perception
1. How We Sense and Perceive the World
●Sensation is the process of receiving stimulus energies from the external environment
and transforming those energies into neural energy
●Perception is the process of organizing and interpreting sensory information so that it
makes sense
●Bottom-up processing means taking in information and trying to make sense of it
● In top-down processing, we begin with some sense of what is happening (the product of
our experiences) and apply that framework to incoming information from the world
● All sensation begins with sensory receptors, specialized cells that detect stimulus
information and transmit it to sensory (afferent
) nerves and the brain
● The sense organs and sensory receptors fall into several main classes based on the
type of energy that is detected
○Photoreception:
detection of light, perceived as sight
○Mechanoreception:
detection of pressure, vibration, and movement, perceived as
touch, hearing, and equilibrium
○Chemoreception:
detection of chemical stimuli, perceived as smell and taste
●absolute threshold, or minimum amount of stimulus energy that a person can detect
●difference threshold The degree of difference that must exist between two stimuli
before the difference is detected.
●Weber’s law is the principle that two stimuli must differ by a constant proportion to be
perceived as different
○ 1 candle added to 20 candles vs 6 candles added to 120
●Subliminal perception refers to the detection of information below the level of
conscious awareness
●Signal detection theory focuses on decision making about stimuli under conditions of
uncertainty
● Expectations influence perception
● Psychologists refer to a predisposition or readiness to perceive something in a particular
way as a perceptual set
● The ability of the visual system to adjust to a darkened room is an example of sensory
adaptation—a change in the responsiveness of the sensory system based on the
average level of surrounding stimulation
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PSYCH 7A Full Course Notes
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Document Summary
Sensation and perception: how we sense and perceive the world. Sensation is the process of receiving stimulus energies from the external environment and transforming those energies into neural energy. Perception is the process of organizing and interpreting sensory information so that it makes sense. Bottom-up processing means taking in information and trying to make sense of it. In top-down processing, we begin with some sense of what is happening (the product of our experiences) and apply that framework to incoming information from the world. All sensation begins with sensory receptors, specialized cells that detect stimulus information and transmit it to sensory ( afferent. The sense organs and sensory receptors fall into several main classes based on the type of energy that is detected detection of light, perceived as sight. Mechanoreception: touch, hearing, and equilibrium detection of pressure, vibration, and movement, perceived as. Chemoreception: detection of chemical stimuli, perceived as smell and taste.
