Sensation & Perception Flashcards
Reception
When receptors for a particular sense detect a stimulus
Receptors
Detect stimulus
Receptive Field
Distinct region of sensory space that can produce a response when stimulated
Found on the body surface and in the muscles, joints, eyes, internal organs
Sensory Transduction
Physical sensation is changed into electrical messages that the brain can understand
At the heart of the senses
Sensation to Perception Stages
Signal > Collection > Transduction > Processing > Action
Neural Pathways
Where electrical information travels to the brain to where it is understood
T/F We sense many more things than we process each second
True
T/F No other factors influence how we understand the sensory information we receive
False
Theories of Perception
Nativist Theory Empiricist Theory Structuralist Theory Gestault Psychology Current theory of perception (innate/sensory and learned/conceptual)
Nativist Theory
Perception and cognition are largely innate and genetic
Born with all perceptual capacities, even though some not present at birth and develop as the individual matures
Opposite of Empiricist Theory (perception is learned and develops as the individual adapts to their environment)
Empiricist Theory
Perception is learned and develops as the individual adapts to their environment
Structuralist Theory
Perception is the sum total of sensory input: one can understand the mind by understanding its basic components
Focuses on Bottom-Up Processing (sensory data and works upward to the brain’s integration of that data)
Bottom-Up Processing
Starts with sensory data and works upward to the brain’s integration of that data
Gestalt Psychology
People tend to see the world in terms of organized wholes rather than constituent parts
Focuses on Top-Down Processing (starts with higher-level cognitive processes and works downward to sensory information)
Current Theory of Perception
Partially innate/sensory and partially learned/conceptual
Threshold
Minimum levels of stimulation needed for detection
Threshold Types
Absolute Threshold
Differential Threshold (JDN)
Terminal Threshold
Absolute Threshold
Minimum amount of a stimulus that can be detected 50 percent of the time
ex. lowest pitch sound
Differential Threshold
Minimum difference that must occur between two stimuli in order for them to be perceived as having different intensities
“Just Noticeable Difference” or “JDN”
Defined by E. H. Weber
Terminal Threshold
Upper limit above which the stimuli can no longer be perceived (highest pitch sound, etc.)
ex. highest pitch sound
Psychophysics
Study of the quantitative relations between psychological sensations and physical stimuli
Term coined by Gustav Fechner 1860 “Elements of Psychophysics”
Psychophysical explanations for perception of intensity
Weber’s Law
Fechner’s Law
Weber’s Law
Applies to all senses, but limited range of intensities
Stimulus needs to be increased by a contact fraction of its original value in order to be perceived as noticeably different.
(formula in book, pg. 25)
Fechner’s Law
Built on Weber’s Law, but more complicated
Strength of stimulus must be significantly increased to produce a slight difference in sensation
(formula in book, pg. 25)
J.A Swet’s Theory of Signal Detection (TSD)
Subjects detect stimuli not only because they can but also because they want to
Factors motivation into the picture, not just math; subjects respond differently (Response Bias)
Response Bias (individuals partially motivated by rewards and costs in detection)
Response Bias
Motivated by rewards, costs
Influences detection of stimuli
Subjects respond differently
What determines different responses to stimuli?
Response bias and stimulus intensity
Responses to Stimuli
False Alarm Hit Miss Correct Rejection Receiver operating characteristic (ROC)
False Alarm
Saying that you detect a stimulus that is not there
Hit
Correctly sensing a stimulus
Miss
Failing to detect a present stimulus
Correct Rejection
Rightly stating that no stimulus exists
Receiver Operating Characteristic (ROC) Curves
Graphical representations of a subject’s sensitivity to a stimulus
How do we see objects in relation to light?
We see the light they reflect
What is light composed of?
Photons and waves measured by brightness and wavelengths
Hue
“Color”
Dominant wavelength of light
Brightness
Physical intensity of light
Eye: Parts
Cornea Lens Ciliary Muscles Retina Receptor Cells Rods Cones Fovea Cells
Visual Pathway to Cerebral Cortex: Parts
Optic Nerve (eye to brain)
Optic Chiasm (half of each eye optic nerve fibers cross and connect to other eye optic nerve %50 crossed; full picture)
Striate Cortex
Visual Association Areas of Cortex
Cornea
Clear protective coating on the outside of the ye
Lens
Located behind the cornea
Ciliary Muscles bend (Accommodate) to focus an image onto the retina
Ciliary Muscles
Bend lens (Accommodate) to focus image onto the retina
Retina
Located back of the eye
Receives light images from the lens
Receptor Cells: 132 million photoreceptor cells and other cells process information
Receptor Cells
Rods and cones
On the retina
Responsible for Sensory Transduction via chemical alternation of Photopigments
Sensory Transduction (converting image into electrical message for the brain to understand)
Rods
Particularly sensitive to dim light
Concentrated along sides of the retina
Used for night vision and peripheral vision
Cones
Concentrated in center of retina, area “Fovea”
Greatest Visual Acuity (best at seeing fine details)
Sensitive to color and daylight
See better than rods because fewer cones per ganglion cell than rods per ganglion cell
Fovea
Area of retina with greatest Visual Acuity (fine details)
Cones (color and daylight)
Visual Acuity
Scale of seeing fine details
Light direction through cells
Horizontal cells > bipolar cells > amacrine cells > ganglion cells (optic nerves)
T/F Stimulus in the left visual field is processed in the right side of the brain, vice versa
True; graph pg. 27 Optic Chiasm
Theories for the details of vision
Opponent-Color/Opponent Process
Trichromatic Theory/Component Theory
Opponent-Color/ Opponent-Process
Theory for color vision
Ewald Hering
Two types of color-sensitive cells exist: cones: blue-yellow response and cones: red-green
When one is stimulated, other is inhibited (no reddish-green colors, see red or green)
Afterimage (look at something red for while, see green when looking at white later)
Afterimage
See green when looking at white after looking at red for a while
Part of Opponent-Color/Opponent Process
“McCollough Effect”
Perceived because of fatigued receptors ; can no longer respond after overstimulated and fatigued so is overshadowed by its opposite
ex. see dark image after staring at white lightD
Trichromatic Theory/Component Theory
Three types of receptors in retina: cones that respond to red, blue or green
Thomas Young and Hermann von Helmholtz
T/F Research shows that the opponent-process theory seems to be at work in the lateral geniculate body, where as the trichromatic theory seems to be at work in the retina
True
Lateral Inhibition
Allows the eye to see contrast and prevents repetitive information from being sent to the brain
Once one receptor cell is stimulated, the others nearby are inhibited
What did David Hubel and Torsten Wiesel discover?
Cells in the visual cortex are so complex and specialized that they respond only to certain types of stimuli
ex. some cells respond only to vertical lines, whereas some respond only to right angles, and so on
Visual Field
Refers to the entire span that can be perceived or detected by the eye at a given moment
Figure and Group Relationship
Refers to the relationship between the meaningful part of a picture (the figure) and the background (the ground)
Depth Perception Parts
(Monocular and binocular cues)
Binocular Disparity (depth)
Apparent Size (size)
Interposition (closer/farther)
Linear Perspective (line distance perception)
Texture Gradient (texture changes)
Motion Parallax (movement overtime for near/far)
Binocular Disparity
Most important depth cue
Our eyes view objects from two slightly different angles, which allows us to create a three-dimensional picture
(fig. pg. 28)
Apparent Size
Gives us clues about how far away an object is if we know about how big the object should be
Interposition
Overlap of objects shows which objects are closer
When one object appears to obscure another, the partially covered object is perceived as being farther away
Linear perspective
Gained by features we are familiar with, such as two seemingly parallel lines that converge with distance
Texture Gradient
Way we see texture or fine detail differently from different distances
The closer the object, the more coarse and distinct the features appear. More distant objects appear finer and smoother in texture
Motion Parallax
Way movement is perceived through the displacement of objects over time, and the way this motion takes place at seemingly different paces for nearby or faraway objects
ex. ships far away seem to move more slowly than nearby ships moving at the same speed
Visual Cliff
Eleanor Gibson and Richard Walk
Developed to study if depth perception is innate
Thick layer of glass above a surface that dropped off sharply. The glass provided solid, level ground for subjects to move across in spite of the cliff below.
Animals and babies were used as subjects
Both groups avoided moving into the “cliff” area regardless of the glass
Originated as market testing for glass-bottom boat excursions
Provided information about depth perception in infants
Dark Adaptation
Result of regeneration of retinal pigment
Mental Set
Framework for assessing a problem and identifying solutions based on our experience
What has worked for us in the past
ex. psychiatrist view symptoms like loss of appetite and lethargy as symptoms of depression, while oncologist might associate with cancer
Pragnanz
Overarching Gestalt idea that experience will be organized as meaningful, symmetrical, and simple whenever possible
Gestalt Ideas: Parts
Closure Proximity Continuation/ Good continuation Similarity Symmetry Constancy Minimum Principle
Closure
Tendency to complete the incomplete figures
Gestalt
(fig. pg. 30)
Proximity
Tendency to group together items that are near each other
Gestalt
(fig. pg. 31)
Continuation/ Good Continuation
Tendency to create a whole or detailed figures based on our expectations rather than what is seen
Gestalt
ex. see two intersection lines, not four line segments
(fig. pg. 31)
Similarity
Tendency to group together items that are alike
Gestalt
ex. see rows of alternating dots (shaded/unshaded), not one continuous block of dots
(fig. pg. 31)
Symmetry
Tendency to group together items that are alike
Gestalt
Constancy
Tendency of people to perceive objects in the way that they are familiar with them, regardless of changes in the actual retinal image
Includes: Size Constancy and Color Constancy
Gestalt
ex. book is perceived as rectangular in shape no matter what angle is it seen from
Size Constancy
Knowing an elephant is large no matter how it may appear
Gestalt: Constancy (tendency of people to perceive objects in the way that they are familiar with them, regardless of changes in the actual retinal image)
Color Constancy
Knowing the color of an object even with tinted glasses on
Gestalt: Constancy (tendency of people to perceive objects in the way that they are familiar with them, regardless of changes in the actual retinal image)
Minimum Principle
Tendency to see what is easiest or logical to see
Gestalt
Classic Illusions: Parts
Ambiguous Figures Figure-Ground Reversal Patterns Impossible Objects Moon Illusion Muller-Lyer Illusion Ponzo Illusion
Ambiguous Figures
Can be perceived as two different things depending on how you look at them
ex. duck/rabbit image or vase/face image
Figure-Ground Reversal Patterns
Ambiguous figures and can be perceived as two different things depending on which part you see as the figure and which part you see as the background
ex. art/fabric pattern looking
Impossible Objects
Objects that have been drawn and can be perceived but are geometrically impossible
Multistability (perception can alternate between two or more possible interpretations)
(fig. pg. 32)
Multistability
Perception can alternate between two or more possible interpretations
ex. Impossible Objects (Classic Illusions)
Moon Illusion
Shows how context affects perception
Moon looks larger when see it on horizon than when we see it in the sky
Horizon contains visual cues that make the Moon seem more distant than the overhead ski. In the overhead sky, we cannot correct for distance when we perceive the size of the moon because we have no cues
Phi Phenomenon
Tendency to perceive smooth motion
Explains why motion is inferred when there actually is none, often by the use of flashing lights or rapidly shown still-frame pictures, such as in the perception of cartoons.
“Apparent Motion”
Apparent Motion
Motion inferred when there actually is none
Part if Phi Phenomenon
ex. flashing lights or quick cartoon frames
Muller-Lyer Illusion
Most famous classic illusion
Two horizontal lines of equal length appear unequal because of the orientation of the arrow marks at the end.
Inward facing arrowheads make a line appear shorter than another line of the same length with outward facing arrowheads
(fig. pg. 33)
Ponzo Illusion
When two horizontal lines of equal length appear unequal because of two vertical lines that slant inward
(fig. pg. 33)
Autokinetic Effect
The way that a single point of light viewed in darkness will appear to shake or move
Reason for this is the constant movements of our own eyes
Purkinje Shift
The way that perceived color brightness changes with the level of illumination in the room
With lower levels of illumination, the extremes of the color spectrum (especially red) are seen as less bright)
Pattern Recognition
Most often explained by Template Matching and Feature Detection
ex. In order to pick the letter “o” out of a page of letters, we would probably first concentrate only on letters with rounded edges and then look for one to match a typical “o”
What did Robert Fantz discover?
Infants prefer relatively complex and sensical displays
What are humans sensitive to in sound?
Loudness & pitch
Amplitude
Physical intensity of a sound wave
Determines loudness
Frequency
The pace of vibrations or sound waves per second for a particular sound
Determines pitch; low frequency is perceived as low pitch or low tone, and vice versa
Measured in Hertz (Hz)
Humans hear best frequencies at 1,000 Hz
Timbre
Comes from the complexity of the sound wave
Major Parts of the Ear
Outer Ear (Pinna & Auditory Canal) Middle Ear (Typanic Membrane, Ossicles, Stapes) Inner Ear (Oval Window, Cochlea, Basilar Membrane, Organ of Corti, Vestibular Sacs)
(fig. pg. 34)
Outer Ear
Consists of Pinna & Auditory Canal
Vibrations from sound move down auditory canal to the middle ear
Auditory Canal
Vibrations from sound move to middle ear
Middle Ear
Consists of Typanic Membrane, Ossicles, Stapes
Typanic Membrane (eardrum) is stretched across the Auditory Canal; behind membrane are Ossicles (three small bones), and last is Stapes
Sound vibrations bump against the Typanic Membrane, causing the Ossicles to vibrate
Inner Ear
Responsible for hearing & balance
Oval Window is tapped by Stapes, vibrations activate fluid-filled, Cochlea, movement of Cochlear fluid activates the Hair-Cell Receptors on the Basilar Membrane and the Organ of Orti.
Traveling Wave
Movement on the Basilar Membrane
Inner Ear
Vestibular Sacs
Responsible for balance
Sensitive to tilt
Respond to hair movement
T/F Receptor cells in the inner ear activate nerve cells that change the information into an electrical message the brain can process
True
Auditory System: Parts
Olivary Nucleus
Inferior Colliculus
Medial Geniculate Body
System leads to Auditory Cortex
What is Hermann von Helmholtz is famous for?
Place-Resonance Theory of sound perception
different parts of the basilar membrane respond to different frequencies
Place-Resonance Theory
Sound perception
Different parts of the basilar membrane respond to different frequencies
Hermann von Helmholtz
Sound Localization
Achieved in different ways
Degree to which one of our ears hears a sound prior to and more intensely than the other can give us information about the origin of the sound
High-frequency sounds are localized by intensity differences, low-frequency sounds are localized by phase differences
Dichotic Presentation
Often used in studies of auditory perception and Selective Attention
In tasks, subject presented with a different verbal message in each ear. Subjects are asked to repeat (Shadow) one of the messages to ensure that the other message is not consciously attended to
Shadow
To repeat what is heard
Olfactory Bulb
Responsible for smell
Hair receptors in the nostrils send messages to Olfactory Bulb
At base of brain
T/F Smell is primitive sense and is strongly connected to memory and perception of taste
True
Five Basic Tastes
Sweet Bitter Sour Salty Umami (new; meaty/savory)
Taste Receptors
“Taste buds” “Papillae”
Lie on the tongue
Saliva mixes with food; flavor can flow easily into the tongue’s taste receptors
Papillae
“Taste Receptors” “Taste Buds”
Lie on the tongue
Saliva mixes with food; flavor can flow easily into the Taste Receptors
Somatosenses
Gives us information about the physical body apart from major sensory organs
Sensory data (touch, heat, pain, pressure, balance, vibration, orientation, muscle movement)
Somatosenses: Parts
Touch Heat Pain Pressure Balance Vibration Orientation Muscle Movement
What does human skin sense?
Touch
Pain
Cold
Warmth
Free Nerve Endings
Detect pain and temperature changes
In the skin
Meissner’s Corpuscles
Receptors in skin that detect touch or contact
Pacinian Corpuscles
Touch receptors that respond quickly to displacement of skin
Two-Point Threshold
Minimum distance between two close objects touching skin to determine there are in fact two instead of one object touching skin
Size is determined by the density and layout of nerves in the skin
Physiological Zero
Temperature that is sensed as neither warm nor cold
Ronald Melzack and Patrick Wall’s Gate Control Theory of Pain
Looks at pain as a process rather than just a simple sensation governed in one center in the brain
Pain perception is related to the interaction of large and small nerve fibers that run to and from the spine
Pain may or may not be perceived depending on different factors, including cognition
Phantom Limb Pain
Occurs when amputees feel sensations of pain in the limbs that have been amputated and no longer exist
Endorphins
Neuromodulators that kick in to reduce or eliminate the perception of pain
Orienting Reflex
Tendency to turn toward an object that has touched you
Vestibular Sense
Allows us to orient ourselves in space and maintain balance
Inner ear in Vestibular Labyrinth (series of interconnected structures continuous with the Cochlea)
Vestibular Labrynth
Series of interconnected structures continuous with the Cochlea
Contains three tubes “Semicircular Canals” (detect head motion and help to maintain equilibrium)
Semicircular Canals
Three tubes in Vestibular Labrynth
Detect head motion and help to maintain equilibrium
Kinesthetic Sense
Awareness of the body’s movement
Spindles (tiny receptors in the muscles throughout the body, provide muscle memory, allowing us to sense how our limbs are moving in space with out visual confirmation)
Related to: Proprioception (cognitive awareness of where our bodies are in space)
Proprioception
Cognitive awareness of where our bodies are in space
Selective Attending
Process of tuning in to something specific while ignoring all other stimuli in the background
ex. what your date is saying vs conversations in the background
Models of Selective Attention
Spotlight Model
Filter Model of Attention
Attenuation Model of Attention
Divided Attention/Multitasking
Spotlight Model
Suggests that humans focus on one particular task while all the other tasks remain in the background until the spotlight focuses on a different task
Attention has: Focus (primarily attended to), Fringe (periphery), and a Margin (limit)
William James
Filter Model of Attention
Says that any information not attended to is filtered out and decays; explain why we are not constantly bombarded with sensory inputs
Sensory input goes from sensory stores through a selective filter, which blocks unattended messages.
Only the information attended to makes it into our working memory
Donald Broadbent
(fig. pg. 37)
Attenuation Model of Attention
Altered Donald Broadbent’s theory of Filter Model of Attention (information not attended to is filtered out and decays)
Addresses Cocktail Party Effect phenomena (person involved in a conversation can detect their name or something equally salient from across a crowded room
Sensory input flows into our sensory stores (Broadbent’s model), but instead of going through a selective filter it goes through an attenuating filter, turning volume down or up on the information
And, rather than decaying, unattended information still goes through higher level processing and into working memory, so it is available on this other channel if need be
Anne Treisman
(fig. pg. 37)
Cocktail Party Effect
Phenomena, person involved in a conversation can detect their name or something equally sailent from across a croweded room
Anne Treisman’s Attenuation Model of Attention
Divided Attention
“Multitasking”
Occurs when a person’s attention is split among multiple tasks
ex. reading a book while listening to music
Research shows that when people multitask, they are more likely to make mistakes and/or move more slowly through their task. This is due to?
Cognitive Load
Cognitive Load
The amount of mental effort involved
Resource Model of Attention
Addresses issue of multitasking/cognitive load, suggesting humans have a limited amount of attention at any given time
Simulations
Use perceptual cues to make artificial situations seem real
Subliminal perception
Is the perceiving of a stimulus that one is not consciously aware of
ex. unattended message in the dichotic presentation or visual information that is briefly presented
Osmoreceptors
Deal with thirst
