Chapter 5 - Sensation and Perception
Sensation (Bottom-Up Processing) - “the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment” (pg. 133)
Perception (Top-Down Processing) - “the process by which our brain organizes and interprets sensory information, transforming it into meaningful objects and events” (pg. 133)
Transduction - “the process of converting one form of energy into another that our brain can use” (pg. 132)
An early research area in psychology
Psychophysics - the study of the relationship between physical stimulation and psychological experience
Absolute Threshold - “the minimum stimulus energy needed to detect a particular stimulus” (pg. 133)
50% of a group detects the stimulus
Signal Detection - Individual absolute thresholds vary with our psychological state (expectations, motivations, and alertness)
Difference Threshold a.k.a., just noticeable difference (jnd) - The minimum difference in stimulation that a person can detect 50% of the time
Weber’s Law - Difference thresholds increase in proportion to the size of the stimulus
Color-sensitive cones are concentrated around the fovea, while the color-blind rods dominate the periphery of the retina.
Brain uses parallel processing of sensory information
Gestalt - German for “form”; “whole”
“The whole may exceed the sum of its parts”
All the parts (what your senses give you) form a whole object in your brain
Just the colors of a bird can’t help you identify it (blue, green, brown could be hummingbird or peafowl), but all parts put together can help you identify the species
Depth Perception - Visual cliff
Need both eyes to accurately estimate depth using retinal disparity
Retinal disparity - objects not being in the same place when off-center in front of you and looked at by one eye, helping you more accurately perceive distance
Two different ways to perceive depth - binocular cues and monocular cues
Binocular cues - use both eyes to perceive depth of objects close to us
Monocular cues - use one eye to perceive depth of objects far from us
Another basic aspect of vision
Provides an adaptive advantage
Troxler Effect - Objects in the peripheral retina disappear under conditions of steady, unmoving stimulation but are revitalized by movement in the periphery
Perceptual Constancy - “Perceiving objects as unchanging… even as illumination and retinal images change” (pg. 149)
Vision perceiving objects shrinking as they get further away BUT knowing they are NOT actually shrinking
The perceived direction of a sound is related to differences in the time at which the sound is received by each ear
Mix of Four Distinct and Basic Senses:
Pressure
Warmth
Cold
Pain
Combination Examples:
Cold + Warm = Hot
Cold + Pressure = Wetness
Touch localization - Noticing where on your body you experience touch
Touch localization is partly dependent on distance of the body part that is touched to the brain
Kinesthesia - “System for sensing the position and movement of individuals body parts” (pg. 159)
Vestibular Sense - “Sense of body movement and position, including the sense of balance” (pg. 159)
i.e., equilibrium
Functions of vestibular system (inner ear):
Maintains balance and upright posture
Controls eye position as we move our heads when viewing objects
Continuous Movement
Currents in the semicircular canals
Compensatory eye movements
Nystagmus - Reflex movement evoked by vestibular stimulation
Our ability to maintain balance depends on visual cues
Related to a cognitive style:
Field Dependence - Rely on visual cues
Field Independence - Rely on vestibular cues
Two Main Theories:
Social Influence Theory - Hypnosis can be explained through other psychological experiences (Putting on an act as a good subject, even subconsciously)
Dissociation Theory - Separating into parts of yourself (Believing when given the suggestion of something)
Dissociation - split in consciousness that allows some thoughts and behaviors to occur simultaneously with others
Hidden Observer - Part of your body still knows what’s going on
Hypnotic Susceptibility - person’s ability to become deeply hypnotized; suggestibility
What affects this:
Ability to become immersed in a role
Absorption - ability to become highly involved in sensory or imaginative sequences
Positive Attitude
Motivation - self motivated for hypnotism works best
Expectancy - skepticism makes it less likely to work
Sensation (Bottom-Up Processing) - “the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment” (pg. 133)
Perception (Top-Down Processing) - “the process by which our brain organizes and interprets sensory information, transforming it into meaningful objects and events” (pg. 133)
Transduction - “the process of converting one form of energy into another that our brain can use” (pg. 132)
An early research area in psychology
Psychophysics - the study of the relationship between physical stimulation and psychological experience
Absolute Threshold - “the minimum stimulus energy needed to detect a particular stimulus” (pg. 133)
50% of a group detects the stimulus
Signal Detection - Individual absolute thresholds vary with our psychological state (expectations, motivations, and alertness)
Difference Threshold a.k.a., just noticeable difference (jnd) - The minimum difference in stimulation that a person can detect 50% of the time
Weber’s Law - Difference thresholds increase in proportion to the size of the stimulus
Color-sensitive cones are concentrated around the fovea, while the color-blind rods dominate the periphery of the retina.
Brain uses parallel processing of sensory information
Gestalt - German for “form”; “whole”
“The whole may exceed the sum of its parts”
All the parts (what your senses give you) form a whole object in your brain
Just the colors of a bird can’t help you identify it (blue, green, brown could be hummingbird or peafowl), but all parts put together can help you identify the species
Depth Perception - Visual cliff
Need both eyes to accurately estimate depth using retinal disparity
Retinal disparity - objects not being in the same place when off-center in front of you and looked at by one eye, helping you more accurately perceive distance
Two different ways to perceive depth - binocular cues and monocular cues
Binocular cues - use both eyes to perceive depth of objects close to us
Monocular cues - use one eye to perceive depth of objects far from us
Another basic aspect of vision
Provides an adaptive advantage
Troxler Effect - Objects in the peripheral retina disappear under conditions of steady, unmoving stimulation but are revitalized by movement in the periphery
Perceptual Constancy - “Perceiving objects as unchanging… even as illumination and retinal images change” (pg. 149)
Vision perceiving objects shrinking as they get further away BUT knowing they are NOT actually shrinking
The perceived direction of a sound is related to differences in the time at which the sound is received by each ear
Mix of Four Distinct and Basic Senses:
Pressure
Warmth
Cold
Pain
Combination Examples:
Cold + Warm = Hot
Cold + Pressure = Wetness
Touch localization - Noticing where on your body you experience touch
Touch localization is partly dependent on distance of the body part that is touched to the brain
Kinesthesia - “System for sensing the position and movement of individuals body parts” (pg. 159)
Vestibular Sense - “Sense of body movement and position, including the sense of balance” (pg. 159)
i.e., equilibrium
Functions of vestibular system (inner ear):
Maintains balance and upright posture
Controls eye position as we move our heads when viewing objects
Continuous Movement
Currents in the semicircular canals
Compensatory eye movements
Nystagmus - Reflex movement evoked by vestibular stimulation
Our ability to maintain balance depends on visual cues
Related to a cognitive style:
Field Dependence - Rely on visual cues
Field Independence - Rely on vestibular cues
Two Main Theories:
Social Influence Theory - Hypnosis can be explained through other psychological experiences (Putting on an act as a good subject, even subconsciously)
Dissociation Theory - Separating into parts of yourself (Believing when given the suggestion of something)
Dissociation - split in consciousness that allows some thoughts and behaviors to occur simultaneously with others
Hidden Observer - Part of your body still knows what’s going on
Hypnotic Susceptibility - person’s ability to become deeply hypnotized; suggestibility
What affects this:
Ability to become immersed in a role
Absorption - ability to become highly involved in sensory or imaginative sequences
Positive Attitude
Motivation - self motivated for hypnotism works best
Expectancy - skepticism makes it less likely to work