Sensation+Perception (Module 2 Ch 4) Flashcards
Memorize by October 10th
Psychophysics
The study of sensation and perception
Sensation
The interaction between your environment and your sense organs
External, objective, occurs first
Perception
Your brain processing, organizing, and interpreting sense information
Internal, subjective, occurs second
Transduction
The time from when the sense information leaves the sensory organ until it reaches the brain
The conversion of physical stimuli into neural impulses or info
Just Noticeable Difference
The smallest change in a stimulus for you to be able to notice that the stimulus has changed
Weber’s Law
The just noticeable difference isn’t fixed, so a stronger stimulus requires a stronger change
Absolute Threshold
How much of a stimulus is required for you to say that the stimulus exists
Differs from person to person
Introverts and people with autism and/or depression tend to be more sensitive (lower absolute threshold)
What is the difference between Just Noticeable Difference and Absolute Threshold?
Looking for change vs looking for existence
Sensory Adaptation
Our sensitivity diminishes when we have constant stimulation
This ensures we notice changes in stimulation more than stimulation itself
What does stimulus detection theory involve?
Stimulus intensity/strength, noise/distraction, and response criteria (how confident you have to be to say yes)
What are the four different responses to a stimulus?
Hit: stimulus + say it exists
Correct Rejection: no stimulus + say there’s no stimulus
False Alarm: no stimulus + say there is
Miss: stimulus + you say there isn’t
What does Liberal vs Conservative mean in terms of response criteria?
More likely to say it exists than doesn’t exists, leading to more false alarms vs more likely likely to say a stimulus doesn’t exists even if it does, leading to more misses
Bottom-Up Processing
Starts at the sensory receptors and works up to higher levels of processing (starting with the data and working up to the knowledge)
Requires more cognitive resources, but tends to be more accurate
Top-Down Processing
Starts at our knowledge or expectations, which influences how we process or perceive the data
Easier but is more likely to be wrong
What is the strongest, most dominant sense in humans?
Vision
Light vs Color
The physical stimulus for vision (which hits us in waves) vs the subjective experience of vision
Wavelength
The distance from one point on a wave to the same point on the next wave
Vision: shorter = cooler, longer = warmer
Frequency
The amount of waves in a given period
Sound: higher frequency = higher pitch
Amplitude
The height of the tallest point of the wave to the lowest point of the wave
Vision: lower = pastels, higher = darker
Sound: lower = quieter, higher = louder
Cornea
The external layer of the eye, whose main purpose is protection
Pupil
The black hole at the center of the eye, where no light reaches
Iris
A muscle in the eye designed to change the shape/size of the pupil, making it larger in low conditions and smaller in bright conditions
Lens
The circular object behind the pupil that focuses the light through the fluid of the eye and onto the retina
Accommodation (in vision)
When the shape of the lens changes depending on where you want to focus your vision
Retina
The back of the eye, where the sensory receptors are for vision
The last step of visual sensation
Fovea
The spot of greatest visual acuity (ie where you see the clearest)
Entirely composed of cones
Rods
A type of photoreceptor that’s active in low light conditions (important for dark adaptation) and works in shades of gray
120 million of them in the eye
Cones
A type of photoreceptor that detects color and fine detail, and requires bright light to function
6 million of them in the eye (mainly in the fovea)
Bipolar and Ganglion Cells
Collect information from the rods and cones of the eye to send through the optic nerve to the brain
The first step of visual transduction
How many cones and rods are connected to one bipolar cell?
One cone sends info to one bipolar cell, but multiple rods can all send info to the same (one) bipolar cell
Blindspot
The part of the retina that the optic nerve connects to
There are no rods or cones here
Myopic vs Hyperoptic
Nearsighted (image hits slightly in front of retina) vs Farsighted (image focuses behind the retina)
Sclera
The whites of the eye, which is important for social interactions in humans
Trichromatic Processing
When it comes to processing color, there are three types of cones in the eye, which each respond to a different wavelength of light
Does everyone have Trichromatic Vision?
Some people have Tetrachromatic Vision, meaning they have a forth cone
Herring’s Opponent Process
The cones of the eye have an opposition process that enhances one color while suppressing another
Afterimages
Visual images that remain after removal of or looking away from the stimulus
Explained by the opponent process theory of color perception
How does color blindness work?
It affects the cones of the eye
What pathway does vision take?
Retina, Optic Nerve, Optic Chiasm, Optic Tract, Thalamus, Primary Visual Cortex
Optic Chiasm
Where information from the left field of vision goes to the right hemisphere of the brain and vice versa
What are the three cells present in the Primary Visual Cortex and what do they respond to?
Simple (orientation info)
Complex (orientation and movement info)
Hypercomplex (multiple forms of orientation info; starts bringing the whole image together)
Feature Detectors
Neurons in the visual cortex that respond only to specific aspects of shapes, such as angles and movement
Where does visual information go after it has been processed by the Primary Visual Cortex?
To the temporal lobe (ventral stream) or parietal lobe (dorsal stream)
Ventral Stream
To the Temporal Lobe
AKA the “what” pathway
Helps with object identification or labeling what you’re seeing
Fusiform Face Area
A region in the temporal lobe that responds primarily to faces
Single Cells
Neurons that only fire/respond to images or thoughts of a specific person and nothing else
Dorsal Stream
To the Parietal Lobe
The “where” or “how” pathway
Helps locate objects in the environment
Tells us how objects are moving in relation to us
Apparent Motion
When you show a succession of images very quickly, it looks like fluid motion
This is how flip books work
Illusory Conjunction
When an image is flashed too quickly for you to have time to combine features or build complete images
What are the two kinds of depth cues?
Binocular (using both eyes) and Monocular (using one eye)
What does Binocular vision do?
Looks for the difference in images picked up by both eyes to determine how far away something is
Familiar Size
We use our familiarity with objects to understand why there might be changes in their size
Ex: if it looks smaller than expected, then it must be further away
Linear Perspective
Parallel lines appear to converge the further away they are
Texture Gradient
The closer things are to us, the more clear their texture
Interposition
Things that are closer to us are in front of things that are further away from us
Relative Height
Things that are closer to us are at the bottom of our field of vision, while things that are further away are at the top
Perceptual Constancy
The brain’s ability to maintain perception of an object’s size or shape despite changes in retinal image
What is Gestalt grouping?
How we decide that two things should be grouped together in our perception
Simplicity or Pragnanz
We process information in the simplest way
Closure
We create closure when closure is not there (ie we perceive a whole object in the absence of complete information)
Continuity
We tend to see things are continuous even if we don’t have reason to see them that way
Similarity
We group similar objects together
Proximity
We groups things based off how close they are to each other
Common Fate
We groups objects together if they are moving together/in the same direction
What affects our perception of sound besides frequency and amplitude?
Complexity/Purity: we are not hearing sounds in isolation; multiple sound waves are reaching our ears at the same time
The more complex, the more difficult to process
What are the parts of the outer ear?
The pinna, auditory canal, and eardrum
Pinna
The fleshy part of the ear, which catches sound waves and funnels them into the ear
Tympanic Membrane
AKA the eardrum
Vibrates based off of how the sound waves hit it
What is inside the middle ear?
An air pocket (which is sealed of by the tympanic membrane)
The ossicles, or smallest bones in our body, which vibrate and amplify sound waves
What are the three ossicles (in order from tympanic membrane to the end of the middle ear)?
The hammer (malleus), anvil (incus), and stirrup (stapes)
Cochlea
Part of the inner ear
The inner organ and last step of sensation
Filled with fluid, which moves based off the vibrations from the stapes
Basilar Membrane
Located in the fluid of the cochlea
Where sensory receptors for the ear are located
Hair Cells
The receptor neurons for hearing, located on the Basilar Membrane
Semicircular Canals
Important for balance
The way the fluid sits in these canals tells your body how its positioned
Place Theory
A theory of sound perception that says that your perception of pitch is based on where movement on the basilar membrane in occurring
Temporal or Frequency Theory
A theory of sound perception that says that sound is processed by how quickly the hair cells are firing (more firing = higher frequency = higher pitch)
Localization
Determining where a sound is located based off of which side of the head the information reaches first and/or which side the info is slightly louder
Location Gestalt Grouping
If two sounds are coming from the same location, we group them together
Temporal Gestalt Grouping
If two sounds start or stop at the same time, we group them together
Music
Grouping notes and instruments together so that other people will process the sound in the way the musician intends
Perfect Pitch
When you can name the musical note that you hear
Associated with a larger, denser temporal lobe
Sensorineural Hearing Loss
Occurs in the inner ear
Issue with the hair cells
More common with age
Hearing aids don’t help very much
Conduction Hearing Loss
Occurs in the middle ear
Issue with the information or vibration being transferred from the tympanic membrane to the ossicles
What are two kinds of skin sensations?
Touch and Pain
Mechanoreceptors
Receptors in the skin that are sensitive to various tactile qualities
What does it mean when we say that touch is a plastic sense?
The somatosensory cortex can change
Phantom Limb Pain
When you lost a limb that your originally had, but sometimes still feel like it’s there and in pain
Nociceptive Pain
Pain from skin and/or tissue damage, detected by nociceptors
Sensitive to temperature, chemical irritation, and pressure
A-Delta Fibers
Responsible for fast, sharp, stabbing pains
C Fibers
Responsible for dull, throbbing pain
Less myelinated than A-Delta
Slower transmission
Referred Pain
There are areas on the spinal cord and/or somatosensory cortex that deal with multiple body parts, both inner and outer, so sometimes the brain confuses which location the pain signal is coming from
Haptic Perception
Understanding our world through touch
Kinesthesia
Your understanding of how your body is positioned and moving
What are chemical senses?
Smell and Taste
Works by connecting molecules to sensory receptors
Why is smell a unique sense?
It doesn’t go through the thalamus, it is directly connected to the olfactory bulb in the forebrain
What are the receptors in your nose?
Olfactory
Papillae
The little bumps of the tongue, which each house hundreds of taste receptor neurons
What are the 5 primary taste sensations? Why are they important?
Sweet, Sour, Bitter, Salty, and Umami/Savory
We associate each one with certain foods (ex: umami = meat, soy, beans)
This influences our cravings, as we crave foods that are bodies might be lacking in (ex: craving an orange because you need vitamin C)
Gustatory Cortex
Where taste sensations are processed
Synesthesia
When a person experiences sensations in one sense when a different one is stimulated
When the senses get mixed up or don’t separate
