Modules 18-24 Flashcards
Light waves
Light (electromagnetic radiation) travels in waves
Can travel through air, empty space–and even some liquids and solids
Often diagramed as single wave, but actually two waves at 90 degrees from each other, one electrical and one magnetic
Amplitude (Light)
Intensity of energy (determines the brightness of light)
Wavelength (Light)
Length in space of each cycle of the wave (determines the hue of light)
Frequency (Light)
How fast the wave cycles (hz = cycles per second)
longer wavelength = lower frequency
shorter wavelength = higher frequency
Wavelength and frequency describe same thing that determines hue of light
Electromagnetic spectrum
Radio waves
Infrared waves
Visible spectrum
Ultra-violet
X-rays
Gamma rays
Scale goes up by frequency/wavelength
Cornea
Outer protective layer
Pupil
Hole for light to get in
Iris
Muscle around pupil allows hole to expand or retract
Lens
Curved structure behind helps filter light
Retina
Layer of photoreceptor cells in eye
Fovea
Point of central focus
Optic nerve
Goes to brain’s visual cortex
Blind spot
Where there are no photoreceptors where optic nerve connects
Visual Pathway
If something is on the left, goes to right side of both eyes, sent to the right side of thalamus, right primary visual cortex
If object on left, light bouncing off object will hit left side of retina in both eyes, down axons sending information to left thalamus and into left primary visual cortex
Retina
Has two types of photoreceptors rods and cones
Rods
Night vision, motion, more in periphery
Cones
Allow color perception more in fovea
Three cone types for short, medium, long wavelengths
No single cone type on its own gives us color information
The ratiosof firing rates between different cone types tell
us the hue of the light
Color vision deficiency “colorblindness”
Occurs when one cone type is absent, not fully functional, or has a tuning curve that is not sufficiently different from another cone size
Helmholtz’s trichromatic theory of color perception
Any color can be represented as position on three continua
Red vs. green
Yellow vs. blue
White vs. black
Can be demonstrated using negative afterimages (desensitization to color increases sensitivity to opposite color)
Opponent processing of motion
Waterfall illusion
Desensitization to unchanging direction of motion causes aftereffect of perceived motion in opposite direction
(if you stare at a waterfall for a while you desensitize yourself to downward motion, thus increased your sensitivity to upward motion, so when you look at a motionless rock it seems to float upwards)
Can occur with multiple directions in different parts of the visual field at the same time
Depth perception
Monocular and binocular depth cues
Monocular depth cues
Only need one eye
Size and height (closeness to horizon) in the visual field
Linear perspective: parallel lines converge in the visual field as they get farther away
Texture gradient: textures appear more densely packed, less spread out and detailed when they are farther away
Interposition/occlusion: if an object is partly blocking another, it must be closer
Atmospheric/aerial perspective (haze): light especially higher frequency light gets increasingly scattered as it travels through the air so more distant objects look fainter, blurrier, and bluer
Relative motion: when you’re moving, closer objects move across your visual field faster than distant objects
Binocular depth cues
Binocular/retinal disparity: the farther away an object is, the more similar its position on the two retinas (because it’s hitting the two retinas at a similar angle)
Binocular depth cues: convergence (how much you have to cross your eyes to focus on the object)
Feature detectors
Neurons that respond to specific features such as shape, angle, movement
Color constancy and lightness constancy
The brain adjusts our perception of color to keep colors constant under different lighting conditions
In the real world, that simplifies perception (objects don’t appear to change color just because lighting changes)
But we can exploit that to create optical illusions by manipulating images to imply different lighting conditions
Top-down process influences perception: we have expectations about what colors things should be
Color constancy and lightness constancy (cube)
In the image, the top-middle
square is made using the
same color as the side-middle
square. But the side-middle
square is implied to be in
shadow, so we perceive it as
a brighter color (because in
the real world, it actually
would need to be a brighter
color in order for It to reflect
the same amount of light as
the top-middle square even
when in shadow).
Color constancy and lightness constancy
We perceive the B square as lighter than the A square because:
It is implied to be in shadow, so in the real world it would have to
be lighter to reflect the same amount of light as the A square
It’s light compared to surrounding squares,
whereas the A square is dark compared to surrounding squares.
We are familiar with checkerboard patterns,
so we expect the squares to alternate
between light and dark.
Sound waves
Sound waves are mechanical waves (they need a medium such as air to travel through)
Oscillation between compression (bunching together) and rarefaction (spreading apart) of molecules
Basically vibration
Sound waves are longitudinal, meaning the oscillation is in the same dimension (in this case the left–right dimension) that the wave is traveling.
But sound waves are typically diagrammed like this, with the vertical dimension representing the amount of compression/rarefaction
The air molecules aren’t actually traveling from left to right. What’s traveling is the energy. Although the regions where the air molecules are compressed are continuously moving from left to right, the Individual air molecules themselves are vibrating back and forth (watch the red ones)
When we diagram a wave like this the horizontal dimension can be thought of either distance or time (because a wave takes a certain amount of time to travel a certain distance through space)
Sound waves don’t actually travel in single straight line
Emanate from sound source in all directions
Amplitude (sound)
Intensity of energy (overall amplitude determines the loudness of sound)
Great amplitude = loud sounds
Small amplitude = soft sounds
Wavelength (sound)
Length in space of each cycle of the wave (determines the pitch of sound)
Frequency (sound)
How fast the wave cycles
Frequency is measured in Hertz (hz) meaning cycles per second
Humans can hear from 20 hz to 20 kHz but gradually lose sensitivity to high frequencies with age so adults can’t typically hear above 16-18 kHz and older adults can’t hear anywhere near that high
Long wavelength = lower frequency = low-pitched sounds
Shorter wavelength = higher frequency = high-pitched sounds
Complex sound waves
Most sounds are complex not simple sine waves without single consistent frequency
We can think of those complex sounds as made up of multiple component sine waves with different frequencies, amplitudes, and phases (starting positions in the cycle), added together
Frequency components
When you turn up the bass or turn down the treble on your stereo, you aren’t making the pitch of the sound lower, but your bringing out more of the lower frequency components within the sound
Fundamental frequency
Frequencies of the component sine waves are multiples of a single frequency (e.g. 100, 200, 300, 400, and 500 hz are all multiples of 100 hz), the lowest frequency is what typically determines the pitch that we perceive
Harmonics
Multiples of the component sine waves of a single frequency
Pinna
Like a cup to catch sound
Ear drum/tympanic membrane
Sound waves enter the ear canal and vibrate the tympanic membrane (ear drum)
Ossicles
Tiny bones that vibrations of tympanic membrane vibrate and that connects the tympanic membrane to the cochlea
Cochlea
Sound waves travel through fluid in the cochlea
Different frequencies stimulate different parts of the cochlea more than others
Sound receptors (hair cells)
Sound receptors in the cochlea transduce that energy into neural impulses transmitted to the brain through the auditory nerve
Semicircular canals
Part of the vestibular system that aren’t directly involved in hearing
Inter-aural differences
If sound is coming from the left, it is louder in the left ear
Inter-aural timing (phase) differences
If the sound is coming from the left, it hits the left ear earlier
Perceiving sound location
Learn to infer high/low, front/back information based on certain frequencies being more emphasized or de-emphasized due to angle at which wave hits pinna
Visual context clues also help
Olfaction
Sense of smell
Detects odorants
Different olfactory receptors in nose detect different chemicals
Most odors that we smell are actually patterns of stimulation of multiple different receptors
Unlike most other types of sensory informaiton, isn’t routed through the thalamus before reaching cerebral cortex
Odorants
small, airborne molecules that have odors and stimulate our olfactory receptors
Olfaction parts
Nasal cavity
Olfactory nerves (with receptors on ends)
Olfactory bulb
Olfactory tract on underside of cerebral cortex carry action potentials directly to the primary olfactory cortex (tract is same thing as a verve except that the word tract is typically reserved for bundles of axons that are entirely contained in the central nervous system)
Taste buds
Clusters of taste receptors
Mostly on tongue but also elsewhere in the mouth
Different types of taste receptors respond to different types of molecules dissolved in saliva
4 basic tastes
Salty: sodium chloride (NaCl) and other salts
Sour: acids (high concentration H+ ions)
Bitter: various molecules including many poisons
Sweet: simple carbohydrates
Additional tastes
Umami/savory: monosodium glutamate (MSG) a salt present in some protein-rich fods
Fat: fatty acids
These additional tastes don’t have entire taste buds dedicated to them but they do have receptors scattered around the tongue
What is responsible for different tastes?
All types of taste receptors are spread across the tongue uniformly
Combination of gustatory (taste) information and olfactory (smell) information give things flavor
Also influenced by tactile information from the mouth
The flavor of chocolate or cinnamon is mostly produced by smell and not by taste per se
Insula
Located deep in cerebral cortex at junction between frontal, parietal, and temporal lobes
Where primary gustatory processing is
Sometimes considered a fifth lobe in itself
Learning
Process of acquiring new information or behaviors
Associative learning
Learning an association between two things (when event A happens, event B tends to happen)
Cognitive learning
Acquisition of information through observation (observational learning) or through experience
Behaviorism
Dominated psychological science in first half of 20th century
Focused on objective measurements
Considered mind as an impenetrable black box where can only measure the inputs (stimulus) and outputs (response)
Classical Conditioning
“Unconditioned Stimulus” (e.g. food) naturally produces “Unconditioned Response” (e.g. salivation)
Neutral Stimulus (e.g. tone) does not naturally produce a response
After repeatedly pairing the US with the NS, the NS becomes a “Conditioned Stimulus” that produces a “Conditioned Response” (e.g. salivation) on its own
Pavlov’s dog
“Little Albert” experiment
Instilled phobia in an infant through classical conditioning
The phobia generalized somewhat to other furry objects
(NS white rat, UCS loud noise, rat becomes CS)
5 major processes in classical conditioning and operant conditioning
Acquisition
Extinction
Spontaneous Recovery
Generalization
Discrimination
Acquisition
Forming the association
Extinction
Classical: Losing the association after CS is repeatedly presented without the US thus turning the CS back into an NS
Operant: losing the association after behavior repeatedly occurs without consequence
Spontaneous recovery
Classical: After extinction association comes back on its own (without reintroducing the pairing) when the CS is presented after a long time has gone by without it being presented
Operant: after extinction, association comes back on its own (without reintroducing the pairing) when behavior occurs after a long time has gone by without the behavior occurring
Generalization
Classical: Extension of association to stimuli that are similar to the CS (e.g. Little Albert associating fluffy white things in general with scary sound)
Operant: Extension of association to similar behaviors
Discrimination
Classical: Distinguishing CS from similar stimuli that aren’t associated with the US (e.g. dog learning only certain pitched tones and not others are associated with food)
Operant: distinguishing conditioned behavior from similar behaviors that aren’t associated with the consequence
Operant conditioning
Type of associative learning involving an association between behavior and consequence
Types of consequences in operant conditioning
Reinforcement (reward) increases the behavior
Punishment reduces the behavior
Positive vs. negative reinforcement
Positive reinforcement: pleasureable stimulus
Negative reinforcement: removal of unpleasant stimulus
Don’t confuse negative reinforcement with punishment
Remember reinforcement is a reward. In this context, positive and negative simply refer to whether something is added or removed respectively.
Primary vs. conditioned reinforcers
Primary reinforcer: naturally rewarding (food)
Conditioned reinforcer: not naturally rewarding but has learned association with reward (money)
Continuous reinforcement schedules
Behavior reinforced every time
Partial (intermittent) reinforcement schedules
Behavior reinforced inconsistently (results in slower acquisition, but also resistance to extinction)
Fixed ratio: behavior reinforced after a certain number of repetitions
Variable ratio: behavior reinforced after inconsistent number of repetitions
Fixed interval: behavior reinforced after certain amount of time
Variable interval: behavior reinforced after inconsistent amount of time
(fixed/variable=consistent/inconsistent
ratio/interval=repetitions/time)
B.F. Skinner
Behaviorist researcher known for his work on operant conditioning
Operant chamber “Skinner box”
Shaping: producing a precise desired behavior by only reinforcing increasingly close approximations of it
Both classical and operant conditioning are highly relevant to the study of these behaviors
Addiction, phobias, and more generally, throughout our lives we form various expectations and preferences and habits through associations
Memory
Persistence of learned information/behavior over time
Recall
Generating the information from scratch (e.g. answering a short-answer or fill-in-the-black question)
Recognition
Knowing it when you see it (e.g. answering a multiple choice question)
Faster relearning
Not needing as much time to learn something the second time implies that the memory from the first time wasn’t completely gone
Ebbinghaus’ Retention Curve
The more times he practiced a list of nonsense syllables on Day 1, the faster he relearned it on Day 2
Information Processing Model of Memory
Considers mind as a computer
Encoding –> storage –> retrieval
Atkinson–Shiffrin model of memory
Stimulus creates a sensory memory (ether iconic “visual” memory or echoic “auditory” memory) attention to this memory turns it into a short-term memory which includes working memory and can be rehearsed to reinforce, it is then encoded into the long-term memory where it can be retrieved back to the short term memory.
Some subliminal information can slip into the long-term memory from sensory memory, but most is discarded if we don’t pay attention to it
Explicit (declarative) memory
Facts and experiences (can be described in words)
Uses conscious/effortful processing
Implicit (nondeclarative) memory
Skills and associations (can be demonstrated through behavior)
Uses unconscious/automatic processing
Long-term knowledge systems
Information can be sent to long term storage and also retrieved from long term storage (e.g. when we memorize a math formula we encode it to long term memory; then when we’re doing a math problem we retrieve that formula from long term storage back into working memory where we can use it)
Phonological loop
Does auditory tasks (e.g. memorizing a series of numbers)
Episodic buffer
Does tasks not covered by other components
Visuospatial sketch pad
Does visual/spatial tasks (e.g. deciding the best route from current position)
Central executive
Controls flow of info, delegates tasks to the other components
Baddely’s model of working memory
One piece of evidence we have separate resources for phonological vs. visuospatial tasks:
It’s more difficult to do two phonological or two visuospatial tasks simultaneously than to do one phonological and one visuospatial task simultaneously (harder to memorize phone number while humming a tune than while drawing a picture)
Conformation that we use phonological loops for memorizing series of digits: people whose native language uses more syllables for digits tend not to be able to memorize as many digits as people whose native language uses only one syllable for most digits
Encoding strategies
Chunking: easier to remember series of numbers in blocks/pairs than as whole series
Deep processing: elaborate, come up with examples and scenarios
Hierarchical organization: organize items into meaningful categories and subcategories instead of just having one big long list
Spaced/distributed practice: practicing for 1 hr/day for 10 days better than studying for 10 straight hours
Testing effect: use flash cards instead of just rereading or recopying notes
Self-reference: connect concepts to yourself and things you’re interested in
Memories stored
Information not stored in single, precise locations in brain but rather distributed across various regions
Reactivation
Much of the same brain activation that was present when experiencing something is reactivated when remembering that experience
e.g. when we visualize something we remember seeing much of the pattern of neural firing is similar to when we were seeing it in the first place
Explicit memory
Semantic memory: facts and general knowledge
Episodic memory: experiences we can replay in our mind
Both largely formed by (not stored in) hippocampus which is one of the last brain structures to mature explaining infantile amnesia
Implicit memory
The cerebellum helps form and store implicit memories such as associations created by conditioning
The basal ganglia are deep brain structures involved in movement; they help form implicit memories for procedures
Emotion and memory
Emotion tends to enhance encoding of memory (emotion suggests meaning and importance)
Flashbulb memories
Vivid memories of intense, unexpected events
But there can be illusory confidence (vividness doesn’t necessarily indicate accuracy)
Recency effect
Items near the end of a list are easier to recall than items in the middle (still in short-term memory and little retroactive interference)
Fades if there is a delay before testing
Primary effect
Items near the beginning of the list are easier to recall than items in the middle (little proactive interference)
Consolidation
Encoding information into a stable, long-term memory
Especially occurs during sleep
Long-term potentiation (LTP): repeated communication between neurons strengthens their synaptic connection
Hebb’s law: “cells that fire together wire together”
Context dependence of memory
Tend to remember information better when we are in same mood/state/environment where we learned or studied it
That’s because of retrieval cues (elements associated with the memory that help retrieval)
