Sensation and Perception Flashcards
Sensation
Detection of “raw” sensory info from the
environment
Perception
Understanding sensory info as meaningful
categories (“Meaningful” associations of raw sensory info)
Sensation is…
The process of detecting stimuli
– Environmental stimuli
– Internal stimuli (like hunger or pain)
Sensory Transduction
To sense the world, you must convert info from
the physical environment into neural impulses
Vision - Sensory Transduction
- Photons of light
Hearing - Sensory Transduction
– Vibrations in the air
Taste and Smell - Sensory Transduction
- Chemicals in air, water, and food
Touch - Sensory Transduction
- Pressure, temperature, vibration
Rods
– light receptors that fire in response to
different light intensities (light vs. dark)
Cones
– light receptors that fire in response to
different light frequencies (colors)
Sound converted to neural signals with…
mechanical engineering
Sound waves move…
tympanic membrane (ear drum)
The Ear Drum…
- moves a set of three tiny bones (ossicles)
- Ossicles send waves through fluid in the cochlea
- The “ripples” cause receptors to move at different
frequencies
Taste and smell converted into neural
signals through…
chemical detection
Taste
- Taste buds detect chemicals in food
Smell
- Receptors in the nasal cavity detect chemicals in the
air
Sense of touch converted to neural signals by…
receptiors that get squished, stretched, and deformed
Nociception
- Specialized receptors for detecting pain
Gate control theory of pain
- Pain may be reduced by increasing other stimulation
Sensory Threshold
- the minimum amount of detectable stimulus
Absolute Threshold
The absolute limit of sensory sensitivity
– What’s the quietest sound you could possibly hear?
Difference Threshold
– “Relative Threshold” or “Just noticeable difference”
– The smallest detectable difference
– How much louder before it actually sounds louder?
Perception is selective
TRUE, Different senses simultaneously active
– Only some things are actively perceive
Bottom-up Processing
The features of the stimulus
Top-down Processing
Influence of past knowledge, expectations, and experience
Perception can use expectations to…
“fill in the blanks”
You are always sensing multiple stimuli but…
only perceive specific stimuli
The grey strawberries are an example of…
Top-down processing (our brain filling in the gaps)
Gestalt Psychology
Perception involves how the mind organizes
patterns of sensations
Law of Similarity
- similar things appear grouped together
Law of simplicity
- Patterns are seen so the resulting structure is
as simple as possible
Law of Continuity
- Lines tend to be seen as following the
smoothest path
Figure-Ground
Object recognition occurs by making
distinctions between the object and
the background
Size Constancy
An object’s size seems constant despite the size of the raw visual image
– Knowledge of the object influences the perception of size
The picture of two rats sitting on the railyard as the exact same size, seems to show a bigger rat in the distance is an example of…
size constancy.
Shape Constancy
Object shape appears to remain the
same even though the visual image
changes
Perception is a combination of…
bottom-up and
top-down processing
Is color seen or perceived?
Percieved - The color you see depends on how your brain interprets it relative to other colors it’s seeing at
the same time
Brain bases its interpretation of color on…
The amount of available light and the presence of other colors
Your perception of color is only an estimate because…
the brain calculates what the color should look like
Perceptions are…
Interpretations of raw sensory information
Perceptual heuristics
“Automatic Shortcuts” the brain develops to interpret perceptions
“light-from-above” perceptual heuristic
- an image of hills flipped upside down will look like valleys based on how our brains have processed light to come from above
Motion detection perceptual heuristic
Alternating patterns of light and dark is a good indication of motion - brains can be fooled into seeing motion
Sine Wave Speech
- Distorted versions of speech that can be
understood if given prior expectation
The McGurk Effect
Perception of language phonemes
altered by visual cues - the mouth moving a certain way makes us believe we hear different things
Don’t necessarily see the world as it is, instead we…
see the world as you expect it to be
Ch. 3 Disembodied Woman
removal of Gallbladder - put on antibiotics
She loses her proprioception
Loses her ability to move her body unless she deeply focuses on it
She needed to use her eyes to compensate.
Proprioception
how our bodies continuously adjust and hold itself in space
Dr. Sacks looks at the disembodied womans parietal lobe because it controls…
so much with physical.
