Sensation and Perception Flashcards
Sense
How receptors detect information
Perception
Interpretation of sensations
Bottom-Up Processing
Analysis of the stimulus begins with the sense receptors and works up to the level of the brain and mind.
Top-down Processing
Information processing is guided by higher-level mental processes as we construct perceptions, drawing on our experience and expectations.
Analysis of the stimulus begins with perception and expectations
Cocktail party effect
You can hear one voice among many
If someone says your name from far away
Selective Attention
Directing our awareness to relevant stimuli while ignoring relevant stimuli in the environment.
Divided Attention
While we can perform some simple motor skills simultaneously (walking and chewing gum), for more cognitively complex tasks, we can focus on only one thing at a time
Inattentional blindness
Failing to see visible objects when our attention is directed elsewhere
Change Blindness
A type of inattentional blindness
The inability to see changes in our environment when our attention is elsewhere.
Choice Blindness
the failure to recall a choice immediately after we have made that choice
- similar faces
Pop-Out Effect
A visual stimulus that has mostly similar-looking objects but one differing object that pops out or stands out very noticeably from the other objects
Absolute Threshold
Smallest detectable level of a stimulus
The minimum stimulation necessary to detect a particular light, sound, pressure, taste or odor 50% of the time. (listening to pitches during a hearing test)
Difference threshold
Just noticeable difference
Ability to sense the difference between 2 stimuli
Weber’s Law
To notice a difference, two stimuli must differ by a constant proportion percentage (not a constant amount)
Signal Detection Theory
Predicts how and when we detect the presence of a faint stimulus (signal) amid background noise (other stimulation).
There is no single absolute threshold
Detection depends on
Person’s experience
Expectation
Motivation
Level of fatigue
Subliminal Stimulation
We process info below the absolute threshold for conscious awareness
To predispose one’s perception, memory, or response
Unconscious processing
Sensory Adaptation
Diminishing sensitivity to an unchanging stimulus
After constant exposure to a stimulus, our nerve cells fire less frequently
An adjustment of the senses to the level of stimulation they are receiving
The constant quivering of our eyes allows us to minimize sensory adaptation for vision
The smell in your friend’s house goes away after a few minutes
Gestalt
Instead of focusing on every small component, we see objects as part of a greater whole and as elements of more complex systems.
The brain creates a coherent perceptual experience that is more than simply the sum of the available sensory information
It does this in predictable ways
Common Region
Objects that are within the same region are perceptually grouped together
Similarity
when objects are similar you group them together
Proximity
we perceive objects which are close to one another as a group
closure
people will fill in blanks to perceive a complete object whenever an external stimulus partially matches that object
Continuity
elements that are arranged on a line or curve are perceived to be more related than elements not on the line or curve
Connectedness
when we see connections in disjointed objects
Figure Ground
Something is a figure and something is a background
Or something is a background and something is a figure
Depth Perception
Enables us to judge distances
Human infants have depth perception
Even newborn animals show depth perception.
Binocular Cues
Depth perception that we have because we have TWO eyes
Retinal disparity - binocular cue
Images from the two eyes differ. (how 3D works)
The amount of disparity (difference) between the two images
Can be used as a cue for distance
Convergence - binocular cue
Neuromuscular cues.
When two eyes move inward (towards the nose) to see near objects and outward (away from the nose) to see far away objects.
The angle formed at the convergence indicates the distance
Relative height
We perceive objects higher in our field of vision as farther away
Relative size
Relative size - If two objects are similar in size, we perceive the one that casts a smaller retinal image to be farther away
Interposition
Objects that block other objects tend to be perceived as closer
Linear perspective
Parallel lines appear to converge in the distance. The more the lines converge, the greater their perceived distance
Relative motion
Objects closer to a fixation point move faster and in opposing direction to those objects that are farther away from a fixation point, moving slower and in the same direction
Light and shadow
Nearby objects reflect more light than more distant objects
Objects that are shaded on top are seen as “sticking out toward us”
Phi phenomenon
The apparent motion created by lights flashing in sequence
Stroboscopic motion
Created by a rapid series of still pictures
dots in a circle
Perceptual constancy
The ability to recognize objects without being deceived by changes in their shape, size, brightness or color even as illumination and retinal images change
Color constancy
We perceive familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object
Color depends on context in its surrounding objects
Size constancy
We perceive objects as having a constant size, even if projected image appears to change sizes
Ponzo Illusion
The distant monster and the top red bar appear bigger because of distance cues.
Ex - A more distant object can create the same-size image as a nearer one only if it is actually larger—the illusion makes the object that is farther away look larger, when in reality it is not
Moon illusion
The moon looks up to 50% larger when on the horizon compared to when it is high in the sky
Adelbert Ames’ room
Even though one girl looks taller than the other, the room is distorted (the girls are actually the same height)
Shape Constancy
We perceive the form of familiar objects as remaining the same even if projected retinal image changes
Lightness/brightness constancy
We perceive an object as having a constant lightness even when its illumination varies
Relative luminance
Amount of light an object reflects is relative to its surroundings
White Objects
Reflect all light, absorb none
Black Objects
Absorb all light, reflect none
Sclera
White
Iris
Colored. Controls size of pupil; regulates amount of light that enters eye
Pupil
Black. Hole. Light enters, hits lens.
Cornea
Covering. Bends light to provide focus
Lens
Light hits here. Shifts shape to focus light
Retina
Membrane at back of eye. “Movie screen.” Where light energy transduced to neural signals
Fovea
Sharpness. Contains cones. Color.
Rods
Shapes
Cones
Color
Ganglion Cells
Connects retina to brain
Blind spot
area of retina where the optic nerve leaves the eye
Optic Nerve
Axons of ganglia, project to brain
Feature Detection
Different parts of the visual cortex detect different components of vision (shape, edges, motion, color).
Parallel processing
doing many things at once
Sound Localization
the ability of an organism to discover the location of something producing sound waves based on intensity and timing
Conduction Deafness
Something goes wrong with the sound and the vibration on the way to the cochlea: eardrum damage, fluid in middle ear, earwax or foreign object located in middle ear.
You can replace the bones or get surgery or a hearing aid to help.
Nerve (Sensorineural) Deafness
The hair cells in the cochlea get damaged. Loud noises can cause this type of deafness.
NO WAY to replace the hairs.
Cochlear implant is possible.
Can be linked to disease, biological changes with heredity, aging, prolonged exposure to ear-splitting noise or music
Cochlear implants
Electronic devices that enable the brain to hear sounds.
Frequency
Long waves…low frequency…low pitch
We measure sounds in decibels
Absolute threshold for hearing = 0 decibels
Amplitude determines loudness
Frequency theory
A sound heard is replicated and matched by the same amount of nerve impulses that are then transmitted to the brain.
This theory falls short as a neuron has a refractory period which does not allow a neuron to fire faster than 500 impulses per second, as the human ear can definitely hear frequencies much louder than 500Hz (can hear up to 20,000Hz)
Place theory
Different parts of the cochlea, in the inner ear, process sounds of different frequencies.
Multiple neurons fire at once either near the opening of the oval window, which transmits lower-pitched sounds.
Five basic tastes
Sweet - energy source
Salty - sodium essential to physiological processes
Sour - potentially toxic acid
Bitter - potential poisons
Umami - proteins to grow and repair tissue
Taste buds
Little bumps on top and sides of the tongue
Taste receptor cells inside taste bud pores
Umami
Savory
Ketchup, anchovies, so sauce, seaweed
Sensory interaction
one sense may influence another
Interaction of smell and taste
McGurk Effect
Change your ears to match what you see
Olfaction
Chemical sense
Odor molecules
Olfactory bulb
Olfactory nerve
In the skin are receptor cells for
Pain
Pressure
Temperature
Touch Localization
Depend on the relative lengths of the pathways from the stimulated parts to the brain.
Hair cells
detect movement and pressure
Vestibular sense
monitors your head’s/body’s position and movement
the inner ear - near the swirly thing
Nociceptors
Sensory receptors that detect hurtful temperatures, pressures or chemicals
Gate-control theory
the spinal cord contains a “gate” that controls whether pain signals get sent to the brain or not
Psychological influences
We edit our memories of pain (which often differ from the pain we actually experienced)
We record pain at the peak moment, register pain at the end
Social-cultural influences
We tend to perceive more pain when others also seem to be experiencing pain
Our experience of pain is much more than neural messages sent to the brain
Synesthesia
The extraordinary sensory condition in which stimulation of one modality leads to perceptual experience in another. Literally, the term means “to perceive together.”
Perceptual adaptation
In vision, the ability to adjust to an artificially displaced or even inverted visual field
Given a new pair of glasses or new contact lenses, we may feel a little strange, even dizzy. Within a day or two, we adjust
Perceptual set
A bias or readiness to perceive certain aspects of available sensory data and to ignore others
Motivation on perception
Motivated individuals may interpret ambiguous stimuli in a way that supports their goals or desires
Motivation influences what individuals choose to focus on. When motivated, people are more likely to selectively attend to information that is relevant to their goals or needs.
Emotion on perception
A person in a positive mood may perceive ambiguous stimuli more positively, while someone in a negative mood may interpret the same stimuli more negatively.
Emotional stimuli often capture attention more easily than neutral stimuli.
- A person feeling fear might be more attuned to stimuli related to potential threats.
Context Effects
Our brain can work backward in time to allow a later stimulus to determine how we perceive an earlier one
Schemas
Used to organize and interpret unfamiliar information
