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Sensation & Perception, Learning

Lecture 02/25/2025: Sensation, Perception, Learning I

• Quiz 2: includes 5.1-5.8 & lectures

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• Sensation = stimulation of sense organs

  • Raw sensory information

  • Ex: waves of light being received by receptors in your retina

  • Input (ex: sound waves, chemical stimulation of tongue)

  • Doesn‘t mean anything until its PERCEIVED

• Perception = making sense of that stimulation

  • selection, organization, and interpretation of sensory input

  • Conscious experience of sensory information

  • Brain is making sense of stimulus

  • Ex: patient w/ brain damage saw a “convoluted red form with a linear green attachment” instead of a rose

  • Ex: “if a tree falls in the forest but there's no one there to hear it… does it make a sound?”--- there’s no one there to perceive the sound

• Transduction = sensory information is translated into signals spread by neurons

  • Stimulation received by appropriate receptor

  • Neurons carry stimulation to thalamus and then to cortex

  • Cortex perceives

• Sensory information: the way we perceive depends on the type of sensory information received

  • Quality:: describes the basic information of a stimulation

    • Different sensory receptors

    • Ex: sweet vs sour

  • Qualitative: magnitude/intensity of stimuli

    • How fast are the neurons firing? 

    • How many neurons are firing?

    • Ex: a light can be brighter or dimmer (think screen brightness)

    • More subtle

  • Quantitative

• Sensory Thresholds: you don’t perceive everything you’re exposed to!

  • Absolute threshold: minimum intensity of stimulation must occur before you experience a sensation

    • How much does it take for you to feel like you perceived something?

    • Stimulus intensity you would detect 50% of the time

    • Ex: Candle flame seen from 30 miles away on a dark clean night is the minimum threshold for human perception

• Difference threshold: “just noticeable difference”, SMALLEST difference between 2 stimuli you can notice

  • How much does something have to change for you to notice the difference?

    • Ex: when commercials are much louder than the show/video you’re watching

    • Ex: shrinking size of a product you usually purchase

      • Manufacturers hope that this is below the just noticeable difference (evil)

      • OR: how much can they cut sugar before people notice?

• Signal Detection Theory:

  • States that perception is NOT objective, instead it depends on:

    • Sensitivity to the stimulus in presence of “noise”

    • “Noise” = anything that’s a distraction that may interfere with your perception of stimuli

    • Criteria used to make judgments from ambiguous information

    • Ex: older patient doesn’t want to wear hearing aids, so they’re going to say they hear things they don’t

  • Need to distinguish REAL responses from response biases

    • Patients can be biased to detect or not to detect

    • Can be “False Alarms” or “Misses”

      • Ex: False Alarm = daughter crying bc mom is doing hair but she’s not touching her

    • Human nature makes us more likely to be biased

  • Helps us capture accuracy by accounting for biases

• Perceiving forms & patterns

  • Same visual input can produce radically different perceptions

  • Ex: Blue black vs. White Gold dress

  • Experience of world is subjective because perception is ACTIVE

    • We are constructing our experience

• Sensory Processing: can happen in 2 ways

  • Bottom-up processing: paying attention to INDIVIDUAL features of stimulus and building up to a perception

    • More likely when something is ambiguous/new

    • Ex: seeing 13 or B on its own

  • Top-down processing: depends on context, we have some expectation/knowledge that influences perceptions

    • Ex: seeing 13 or B with context

• Constructing perceptions

  • We ACTIVELY CONSTRUCTING our perceptions

  • Most perceptions involve more than one sense!

  • Ex: what is a kiss like?

  • Ex: losing smell from COVID

  • Ex: McGurk effect 

    • What we see overrides what we hear

    • Ba vs Fa

  • Ex: Synesthesia 

    • Certain neurons stimulate different senses @ the same time

    • Ex: associating numbers w/ colors, certain music can sound blue

    • Pherell Williams sees certain colors in his mind when he hears certain notes

    • Podcast for extra credit option has one abt synesthesia for apa!

• The Visual System

  • We as a culture & in science talk a LOT about the vision

  • Ex: “dark times”, or “the eyes are the window to the soul”

  • Psychological research is also biased toward vision!

  • Impressionists = talk about how LIGHT changes the way we perceive things

  • Expressionists = used color to symbolize experience

• The Eye: KNOW THE PARTS OF THE EYE FOR QUIZ

  • Cornea: transparent window at front/outside of eye

  • Iris: Colored ring of muscle surrounding pupil

    • Constricts & expands to regulate the amount of light coming into pupil

    • Dilated =  less sharpness but more visibility

    • Constricting = sharpens image

  • Pupil = black opening at center of iris that 

  • Lens = INTERNAL transparent structure that focuses the light rays falling on to the retinal

    • Forms an upside down image on retina

    • Accommodation = when your lenses adjust to focus!

      • Focus on close object = eye gets rounder

      • Focus on distant objects = eye gets flatter

    • Common lens problem

      • Nearsightedness= close objects are clear, distant objects are blurry

      • Farsightedness= distant objects are clear

      • Cataract = lens becomes clouded

• Retina = paper thin neural tissue lining back of eye, 

  • Absorbs light

  • Processes Image

  • Sends information to brain

  • Damage can cause BLINDNESS

  • Contains millions of light sensitive receptors

• Nerves receiving from retina cells are like a ponytail bundled together and exit eye to optic disk 

• Optic nerve fibers = converge at a SINGLE spot 

• Fovea= spot in center of retina that contains only CONES

• Types of Specialized Visual Receptors

  • Cones = (CO- COLOR, CO-COnes)

    • Daytime vision (Daylight) & Color vision

  • Rods = specialized visual receptors that play a key role in night vision & peripheral vision

Vision & The Brain

• Light falls on the eye, but you SEE with your brain

• Retina receives & processes and sends to brain for interpretation

  • Axons leave back of eye and travel to optic chiasm

  • Axons from half of each eye cross over

• Thalamus has occipital lobe (primary visual cortex)

Lecture 2: Sensation & Perception 2:

• Sensation = raw sensory stimulation

• Perception = selection, organization, and interpretation of input

  • us making sense of it

  • An ACTIVE construction

• “Blind spot”: no receptors are present, so we can’t receive information

  • Why don’t we usually perceive our blind spot?

  • Our eyes are subtly moving all the time to receive more information and fill in the blind spots/fill in the blanks

• Light falls on eye but you SEE with your brain

  • Retina processes and sends information to brain 

• “What and Where” pathways

  • visual areas beyond primary visual cortex form 2 parallel processing pathways

  • Ventral stream (“What stream)”: projects from occipital lobe and specialized for perception and recognition of objects

    • What is this object

    • Damage can cause visual agnosia (inability to recognize objects, can see color/structure but can’t recognize objects themselves)

  • Dorsal stream (“Where stream”): projects from occipital lobe to parietal lobe and is specialized for spatial perception (determining WHERE an object is)

    • Think dorsal fin of dolphin 

• Visual Processing of Faces - Facial Perception

  • Humans = social animals, use faces to:

    • Differentiate from unique individuals

    • Judges people’s moods & attention

    • Allows you to discern someone’s age, race, sex, etc.

      • Ex: Still face experiment

  •  There’s evidence for processing faces differently

  • Prosopagnosia = unable to process faces

  • Face inversion effect: when faces are presented upside down, they are harder to recognize (as compared to other objects)

  • Margaret Thatcher Illusion: faces with inverted species when presented upside down are harder to distinguish

  • Prosopagnosia: specific deficit in the ability to recognize faces, despite ability to recognize other objects

    • Specific to facial recognition

    • Developmental prosopagnosia: present from birth

    • Acquired prosopagnosia: acquired following a brain injury

  • Fusiform gyrus: a region of temporal lobe critical for perceiving faces

    • Damage to this area is associated with prosopagnosia

• Color Perception

  • In order to see, there MUST be light

  • Light = electromagnetic radiation that travels in waves, which have:

    • Amplitude = height is brightness

    • Wavelength = distance between peaks is hue

    • Purity = variation is saturation of light

  • Color wavelengths translate into whatever object we have around us

  • An object appears to be a particular color because of the wavelengths of the light it reflects

    • Colors don’t actually exist in the physical world!

    • We have receptors for long wavelengths: red & orange

    • Medium: red & green

    • Shorter wavelengths: blue & Violet

      • Causes ambiguity between purple and blue sometimes

  • Trichromatic Theory of Color Vision: “3 main color groups”

    • Eyes have 3 types of cones tailored to 3 different wavelengths of light

      • Red, Green, Blue

    • We can see EVERY color in the rainbow b/c eyes do their own “color mixing” by varying ratio of neural activity from 3 types of receptors

      • Evidence: light of ANY color can be matched by combo of red, green, and blue

      • Light mixes differently than color!

        • Mixing all different types of light together will get you WHITE, while mixing color which makes it darker and darker

        • Turns white because there’s more light!

      • Color blindness: variety of deficiencies in the ability to distinguish among colors

        • Most common is ability to only see 2 colors, note 3 due to missing receptors

        • Serves as evidence for trichromatic theory, as one receptor is missing

  • Opponent Process Theory: color perception depends on receptors that make a antagonistic responses to three pairs of colors

    • The antagonist response means that opposing color gets stimulated

    • Loophole in trichromatic theory: don’t describe colors using only red, green, blue!

    • Afterimage = a visual image that persists after a stimulus is removed

      • Ex: seeing the dots after someone shines a light

    • When you perceive an afterimage, it's the complimentary color

      • Red vs. Green

      • Yellow vs. Blue

      • Black vs. White

• BOTH Trichromatic & Opponent Process Theory are TRUE

  • The eye has 3 different types of cones sensitive to 3 diff. Types of wavelengths

  • Cells in retina, thalamus, and visual cortex respond in OPPOSITE ways

• Making sense of visual stimuli:

  • Often, The world is more ambiguous than we realize

    • We have to hypothesize about perceptions of sensory information

    • Ex: Young lady vs. Mother in law

    • Context guides perceptual hypotheses

      • Ex: Orange jello ran out so chef used yellow w/ food dye and no one complained

• Figure & Ground

  • We naturally divide scenes into: (for bottom up processing)

    • Figure = thing that’s being looked at, the feature

    • Ground = background surrounding the figure

      • Ex: illusion w/ faces & vase, where vase is figure while black is background, black is figure while white is ground

• Gestalt principles = idea that we are perceiving some form out there in the world

  • Ex: List three or 5 of Gestalt principles, briefly describe, and give an example of each. (Might be on the test!!!)

  • Proximity: things that are near one another seem to belong together

    • Ex: 4 lines of little blue circles

    • Ex: students who sit together (are they together?)

  • Closure: we assume things are WHOLE

    • We group elements to create sense of completeness or closure

    • May fill gaps to make sense of it

      • Ex: Letter E but w/ white gaps, panda

  • Similarity: we GROUP items that are SIMILAR

    • If things are the same, we think they go together

    • Ex: turning on a sports channel and quickly identifying who’s on same team and who’s an opponent b/c opposite sides/jerseys

  • Simplicity: we see things as the simplest version POSSIBLE

    • Ex: 2 rectangles making an X vs. 5 little diamonds that are laid out just so that they are adjacent to each other to form a cross

    • Simplicity tends to win

  • Continuity: “Closure idea”, we fill in gaps to connect dots & make wholeness

    • Ex: Baby in prison vs. Bars of a crib

    • Ex: Individual dots fill out into a line mentally

  • Illusory Contours: “False Shapes/Boundaries”

    • We perceive boundaries (contours) as depth cues, even when they don’t exist!

  • Common Fate: Visual elements that move together are grouped together

    • Ex: school of fish moves together, so we perceive them as a WHOLE

• Perceptual Constancy = through experience w/ gravity & objects, we learn that things have stable characteristics

  • Tendency to experience a stable perception in the face of continually changing sensory input

  • Ex: not being shocked by a notecard having a blank side on the back, or by flipping it over, upside down, etc. (rotating paper)

  • Ex: view objects as having a stable size, color, brightness, and location

  • Ex: inflating a balloon is surprising to a baby

• Misleading cues

  • Visual illusions =  apparently inexplicably discrepancy appearance and perceptual reality 

  • Visual illusions work b/c we have expectations that we might not be aware of

  • Ex: which is wider, table A or B? Longer? (they’re actually the same table)

  • Ex: feeling fuller when portions are on smaller plate (they look fuller, and so you feel fuller)

• Depth & Distance

  • Depth perception 

    • Binocular depth cues: based on differing views of 2 individual eyes

      • Retinal disparity: object within 25 feet project images slightly differently

        • Distance between eyes causes brain to do mental trigonometry b/c of the distance between your eyes

        • Closer objects produce greater disparity 

          • Give brain information about distance

          • Must have 2 working eyes to perceive depth!

  • Monocular depth cues = things you can perceive with only one eye/flat image that suggest depth

    • Based on image in either eye ALONE

    • Learned experience from use of eye

    • Identify which of the monocular depth cues being used here (in an image)

    • Linear perspective:

    • Texture gradients/Relative clarity:

    • Inclusion: if something’s in front, the other thing is behind

      • Ex: sphere blocking sphere

    • Relative size

      • Ex: men sitting in chairs in hallway

    • Familiar size

      • Ex: men sitting in chairs in hallway

    • Position relative to horizon:

    • Light & shadow:

    • Our learning about the way things look/are impact our perception

    • Motion parallax= when observing moving objects, closer ones appear to move faster than those far aways

    • Ex: Birds vs planes

03/04/2025: Lecture 3 (Sensation & Perception 3)

• Encouraged use of bullet points/Charts in essay questions instead of paragraphs

• Better to guess than leave blanks

• Audition = Hearing 

  • The sense of sound perception

  • Sound waves: a pattern of changes in air pressure during a period of time, produces the precept of a sound

    • Amplitude = loudness

      • Bigger waves, higher height

    • Frequency = pitch of sound

  • Sound waves arrive @ person’s outer ear, sound waves travel through eardrum, 

  • vibrate 3 bones (called the ossicles, 3 tiny bones called hammer, anvil, stirrup) which vibrate cochlea, oval window (membrane in the cochlea), cochlea = fluid filled coiled tube,  which stimulate fluid inside cochlea and move stereocilia, 

  • Basilar membrane = runs through cochlea; cochlear fluid makes it oscillated which stimulates hair cells to bend

    • Different sounds vibrate @ different locations on basilar membrane

    • High pitched = near base of basilar membrane

    • Lower pitched = closer to top of basilar membrane

    • snail-shaped

  • Hair cells: primary auditory receptors, send info to auditory nerve, which travels to thalamus & primary auditory cortex

  • Eardrum.Tympanic membrane : a thin membrane @ beginning of middle ear, sound waves causes it to vibrate

  • Perception done by the brain

  • Pitch is encoded by frequency & location

    • Temporal coding: looking at LOW frequency stimuli & the rate of firing of cochlear hair cells (hair cells match frequency of sound wave)

      • Low frequencies = up to ~4,000 Hz

    • Place coding: mechanism for encoding high-frequency auditory stimuli in which frequency of sound waves in encoded by location of hair cells along basilar membrane

  • Sound Localization: not only identifying what the sound is, but where it is coming from

    • Similar to binocular disparity

    • Brain integrates the different sensory info. Coming from each ear

    • Ex: Barn owls in the dark looking for prey

  • Vestibular system: perception of balance determined by receptors in the inner ear

    • Machinery related to balance is also intertwined with our auditory senses!

    • Ability to know where you’re located in the world and what you need to do

    • Uses info from receptors in the semicircular canals of inner ear

      • Contain a liquid when head moves, hair cells @ end of canal bend

      • Bending of hair cells generates nerve impulses that inform us of head’s rotation

    • Body’s sensory of where they are in the world

    • Ex: dizziness, being seasick or carsick, vertigo, etc.

  • Cochlear Implants

    • Cochlear implantation has helped people w/ severe hearing problem due to loss of hair cells in the inner ear

    • For people born deaf or w/ hearing damage/loss

    • Works by directly stimulating the auditory nerve, but doesn’t amplify sound

      • Rerouting sounds to come from electronics/computer

      • Best results in tiny babies b/c their brains are still plastic

    • Controversial because of the idea of “Audism”

      • “Fixing people” is offensive

      • Results for folks who are older than infants aren't as great 

  • Hearing Habits 

    • Wearing headphones/earbuds w/ super loud music a lot is a known cause of hearing loss

      • Can damage hair cells

      • Listen @ lower volumes & use earplugs for noisy environments

      • More pressure, more often = more damaging

      • Ex: young people listening to 92.6 decibels in NYC

      • Use apps to determine how loud/test your own habits

• Olfaction = Smell, Gustation = Taste

  • These senses are RELATED

    • External signals that trigger both taste and smell are CHEMICAL

  • Taste:

    • 5 basic sensations

      • Papillae:  raise bumps on tongue that have taste buds

      • Taste buds: within the papillae, sensory organs in mouth (NOT JUST ON TONGUE), contain receptors for taste

        • Send signals to thalamus

      • Diff types of tongue have diff receptors for taste, but they are distributed throughout the tongue

        • Sweet

        • Sour

        • Salty

        • Bitter

        • Umami (Japanese for savory/yummy)

        • Most foods are a mixture of 5 basic qualities!

        • “Mouthfeel” = texture of diff. Foods (ex: avocado vs chips)

      • Cultural influences can impact taste preferences!

        • Begin in the womb!

        • Ex: carrot juice vs. water before being born, etc.

        • What your mom was eating before you were born affects your taste preferences later on

    • Supertaster = having a higher density of papillae and therefore more taste buds

      • Underlying genetic factors

      • Tend to be: younger (lose tase buts with age), female rather than male

    • Nontaster = less density of taste buds, less dense taste experience

• Smell: does NOT go through thalamus!

  • Detection of odorants

  • Olfaction: sense of smell

  • Basic process:

    • Odorants pass into nose & nasal cavity

    • Contact olfactory epithelium (which contains receptors for smell)

      • Olfactory epithelium: a thin layer of tissue, within the nasal cavity, that contains the receptors for smell

      • Has Olfactory sensory neurons 

    • Tracts to Olfactory bulb: the brain center for smell, located below frontal lobes

      • pleasant/unpleasant smell is processed in brain’s prefrontal cortex

      • Intensity of smell is processed in areas of brain associated w/ emotion & memory

    • Hyposmia: reduced ability to detect odors

    • Anosmia: no sense of smell

    • phantosmia: smelling an odor that isn’t there

    • Parosmia: change in normal scent of odors

    • Goes to amygdala, associated with memory & STRONG EMOTIONS

      • Certain smells can have bigger associations with strong emotions

• Haptic Perception = Touch

  • Skin Contains receptors for touch

  • Anything contacting skin provides tactile stimulation

• Nociception = Pain

  • Congenital Insensitivity to Pain

    • Can be dangerous, can lead to early death b/c no pain signals (ex: appendix burst but they didn’t know)

  • The way we think about pain has a lot to do w/ emotional, physiological, and social aspects

    • Physiological aspect: different types of neurons respond to diff. Pains

      • Fast fibers = Sharp pain signals  

        • Myelinated

        • More efficient

        • Ex: OW!

        • Ex: burning fingers, pricking fingers, etc.

      • Slow pain fibers = dull, aching pain

        • Unmyelinated

        • More inefficient

        • Ex: ow ow ow ow ow ow

  • Somatosensory cortex helps identify & locate pain

  • There are different factors that determine when you’ll experience more or less pain

    • Gate Control theory: painful impulses from the pain receptors only reach the brain if the “gate” is open

    • Opening the gate: makes pain more likely to occur

      • Anxiety

      • Depression

      • Boredom

    • Conditions that close the gate:

      • Counter Stimulation makes pain less likely to occur

      • Distraction/Intense focus/concentration

      • Medication

      • Relaxation

03/06/2025: Learning

• On exam: Be able to label parts of the ear!

• On exam: different types of receptor cells (for vision, audition, taste and smell), see textbook table

• Learning = any relatively durable change in behavior or knowledge that is due to experience

• Humans & Beyond

  • Ex: human immune system learns what are pathogens

  • Ex: type of learning that can contribute to disorders to OCD

• Types of Learning:

  • Nonassociative learning: learning to adjust responses based on repeated stimulus

    • Based on noticing how you react to things, no rewards/punishments

    • Habituation: when our behavior response to a stimulus DECREASES

      • Ex: habituating to the surrounding greenery in summer

      • Dishabituation: opposite of habituation, dehabituating/attention being grabbed/being sensitive to surroundings as falls turn colors in fall

    • Sensitization: when our behavior response to a stimulus INCREASES

      • Desensitization: opposite of sensitization, when people become “desensitized” to stuff

      • Ex: Dog became sensitized to thunderstorms, became scared of them, another dog became desensitized to thunderstorms and isn’t as scared of them anymore

  • Associative learning: learning about the link/connection between 2 stimuli or events that go together

    • Can be conscious/unconscious

    • Stimulus = anything that can provoke/trigger some sort of mental/physical/behavior change (response)

    • Response = the reaction to stimulus

    • Classical conditioning: learning in which one stimulus gains the ability to invoke a response that another stimulus previously associated with another stimulus, making subtle and often physiological connections

      • Ivan Pavlov’s dogs (1903)

      • Studying digestion & role of saliva

      • Accidentally discovered this

      • Presented meat to dogs to produce & collect saliva

      • Presence of food tends to make dogs salivate

      • Dogs would start salivating before the food was even given to them, when they heard then sounds, music, lights (neutral stimuli) when he was preparing the food

      • Dogs began to associate unrelated stimuli (the metronome, NOT A bell!) and began to drool at the ticking itself (even without food) → conditioned reflex

      • Meat produces → salivation (no conditioning required)

      • Metronome (NS) + Meat (US) → Salivation (UR)

      • Metronome (NS) + Meat (US) → Salivation (UR)

      • Metronome (NS) + Meat (US) → Salivation (UR)

      • Metronome (NS) + Meat (US) → Salivation (UR)

      • Metronome (CS, conditioned stimulus)→ Salivation (CR)

      • Unconditioned stimulus (US) = evokes an unconditioned response (NOT LEARNED), meat produces the saliva 

      • Unconditioned response (UR) = unlearned response to unconditioned stimulus that occurs without previous conditioning

      • Neutrals stimulus (NS) = a stimulus that is not associated with response

      • Conditioned Stimulus (CS) = previously neutral stimulus that can evoke a conditioned response

      • Conditioned Response (CR) = a learned response to a conditioned stimulus because of prior conditioning

      • Classical conditioning in everyday life:

        • Anxiety/phobias: dentist’s drills, scary music in movies (ex: the shining but happy, harry potter but sensual)

        • Physiological processes: arousal to coffee smell, food aversions (ex: throwing up b/c of Fritos, stu food, freshens), some fetishes some placebo effects, scent associations (ex: ex’s cologne), song associations

        • Ex: food aversion

          • Illness (US) → Nausea (UR)

          • Oreos (NS) + Illness (US) → Nausea (UR0

          • Oreos (CS) → Nausea (CR)

      • Acquisition = acquiring/the beginning, first stage of learning something

        • Depends on:

          • Stimulus contiguity = the closeness of stimuli in time and space

          • Ex: the closer the bell and meat are in time, the easier it is to make that connection between those stimuli

          • Why it’s hard to stick to healthy habits

          • Stimuli are more likely to be conditioned if they are: novel, unusual, unexpected, or especially intense

        • Extinction = gradual weakening of and disappearance of a conditioned response

          • Happens when conditioned stimulus (CS) is repeatedly presented without unconditioned stimulus (US)

            • Ex: Bell with no meat

          • Time taken to extinguish depends on time taken to establish connection in first place

          • Spontaneous recovery = reappearance of an extinguished response after a break

            • Ex: no meat after bell, but on another day dog salivates anyway

        • Rescorla-Wagner Model = animals learn some stimuli are better predictors than others

        • Prediction Errors affect learning

          • Positive (presence) prediction errors: unexpected event occurs that strengthens the conditioned stimulus (CS) and Unconditioned Stimulus (US) association

            • Ex: dog is surprised by food b/c they didn’t hear can opener

            • Ex: watermelon cake tastes like cinnamon

          • Negative (absence) prediction errors: unexpected event does NOT happen, weakens Conditioned stimulus and Unconditioned stimulus association

            • Ex: can opener is working for your soup, dog = surprised 

      • Stimulus Generalization = when your conditioned response occurs with a stimulus is SIMILAR to the original stimulus

        • Ex: if all coldplay songs make you sad, snake phobia and jumping @ anything that looks like a snake

      • Stimulus Discrimination = when you DON’T get a conditioned response to a similar stimulus

        • The more distinct, the more discrimination

        • Knowing the diff between 2 things/stimuli

      • Higher-Order/Second-Order Conditioning = when a conditioned stimulus can be used to create additional conditioning

        • Ex: associating red hats with Donald trump, so red hat evokes feelings about trump and MAGA

    • Operant Conditioning:  Rewards and Punishments, association of voluntary action and a consequence, learning in which voluntary responses are controlled by their consequences

      • Described by Thorndike (first), Skinner, Watson

        • You’re gonna do things that lead to good consequences more, and do less of bad things (Law of Effect)

        • Law of Effect: any behavior that leads to a “satisfying state” of affairs is likely to occur again, and any behavior that leads to an “annoying state of affairs” is less likely to occur again

        • Thorndike and Skinner = cat in puzzle box, “Skinner box”

        • Ex: Pigeon “ping pong” competition for food

        • John B. Watson: shaped behaviorism, wanted to observe behaviors rather than thoughts

      • Reinforcement = an event following a response increases an organism's tendency to make that response

        • Usually provide some sort of reward

        • Ex: getting extra credit for asking a question

        • Applies to humans & animals

        • +/- doesn’t mean good and bad

        • Positive = presented

        • Negative response = taken away

        • Positive reinforcement (PRESENTED): when a response is STRENGTHENED b/c it is followed by the PRESENTATION of a REWARDING stimulus

          • Rewards

          • Working is rewarded by paycheck, makes you continue going to job

        • Negative reinforcement (ABSENT): when a response is STRENGTHENED b/c it is followed by REMOVAL of something bad/unpleasant stimulus

          • Because rats pushed buttons, they are not electrocuted

          • Ex: doing it to make sure your parents can stop hounding you for it

          • Ex: seat belt noise until you buckle up

          • Trick Question: Does negative reinforcement mean the opposite of positive reinforcement (reward)? 

            • NOOOOO

      • Types of reinforcers:

        • Primary = reinforcers that are inherently reinforcing because it satisfies the biological need

          • Ex: food, water, warmth, sex, affection

          • When working with animals, primary reinforcement works better

• Secondary reinforcement = reinforcer that acquires reinforcing power by being associated with primary reinforcers

  • Depend on learning

  • Ex: money, good grade, attention, flattery, appraise, applause

• Punishment = when consequence WEAKENS the tendency to make that response

  • Positive punishment = PRESENTING a stimulus decreases the likelihood of a behavior

    • Make a response LESS likely

    • Ex: getting rejected harshly discourages you from asking ppl out again

  • Negative punishment = REMOVING a stimulus decreases the likelihood of a behavior

    • Make a response LESS likely

    • Ex: parents taking away privileges

  • Test yourself with the slides!

• Social learning: 

• Operant conditioning = rewards & punishments

• Positive = presented

• Negative = taken away, absence

• Punishment= trying to STOP a behavior/make it less likely to occur

• Reinforcement = trying to encourage a behavior/make it more likely to occur

• Positive reinforcement: ex: sugar water if bar is pressed

• Negative reinforcement: taking away something BAD, response is strengthened because it is followed by REMOVAL of unpleasant stimulus

  • Ex: keep cleaning your room b/c then your parents won’t nag

  • NOT Punishment (punishment = trying to STOP  a behavior)

• Punishment = when consequence weakens tendency to make that response

  • Positive punishment = presenting something bad 

  • Negative punishment = removing something good (ex: taking away freedoms)

• Primary reinforcers: reinforcers that inherently present a biological need

• Secondary reinforcers: reinforcers that acquires reinforcing power by being associated with primary reinforcers

  • Typically used in humans

  • Ex: money, good grades

• Types of Reinforcers:

  • Intrinsic = coming from within, inherently related to activity being reinforced

    • Ex: enjoyment, satisfaction, pride

    • Ex: feeling pride when you go for a run/study well everyday/satisfied with your work

    • Better for motivating behaviors LONG TERM, maintaining behavior changes

  • Extrinsic = coming from externally, not inherently related to activity being reinforced

    • Ex: Money, applause, hugs to study more

    • Ex: being bribed

    • Better for motivating NEW behaviors, INITIATING behavior changes

  • Start w/ extrinsic rewards → Intrinsic rewards develop

• Reinforcement over time:

  • Animals can take a long time to perform the exact desired behavior

  • How do I reinforce more quickly?

    • Shaping: reinforcing behaviors that are increasingly similar to desired behaviors

      • Successive approximations: starting with any behavior that even slightly resembles the desired behavior

        • Ex: swimming school, training dolphins to dance

  • Time impacts operant conditioning!

    • Longer delays result in unlearning the behavior!

    • Ex: why you shouldn’t yell at your dog for stuff they did while you were not home

  • Temporal Discounting: when the value of a reward diminishes over time, means “less and less and less”

    • Ex: money is less valuable to us if it’s far away (would you rather have $10 rn or $20 a year later?)

  • Schedules of Reinforcement (how are we allocating rewards to strengthen behavior): pattern of presentation of reinforcers over time, how many behaviors are being rewarded

    • Continuous reinforcement (all being rewarded): every time you do the thing, you get the reward, very predictable

    • Intermittent/Variable/Partial reinforcement (some are rewarded): sometimes, not as predictable, sometimes you get reward and sometimes you don’t, not as predictable

    • Which one produces a LONGER LASTING behavior change? Intermittent reinforcement, unpredictable makes you learn it b/c you want to remember the reward (ex: dog wants the treat, is gonna ask for it b/c it doesn’t know), if you never know, you put more effort into it

      • Ex: Lottery, Praise from teachers, 

    • Which one produces a shorter term behavior change? Continuous reinforcement, if the reward ever goes away, it’s easy to learn that reward is gone, behavior is easy to unlearn

    • Interval Schedules: reinforcement depends on the amount of time passing

      • Fixed interval schedule: reinforcer is given after a stable time interval

        • Ex: every 3 weeks

      • Variable interval schedule: reinforcer is given after responses following a VARYING time interval

        • Ex: once every 2 min on average (can be after 1, 2, 3 min)

        • Ex: Radio contests had 2 tickets each hour but you don’t know when in the hour (minute 5 vs 55 vs 15)

    • Ratio schedules: number of times needed to get rewarded, the number of times the response must be made to get reinforcement

      • Fixed ratio schedule: reinforcer is given after stable/fixed # of responses

        • Ex: sell 5 cars and get a bonus

      • Variable ratio schedule: reinforcer is given after a CHANGING or VARIABLE # of responses

        • Ex: slot machine pays out after every 100 tries, on AVERAGE (you never know WHEN it will actually pay out)

      • Continuous, Fixed & Ratio learning is Faster but easier to extinguish

      • Variable learning is slower but stays long term (lasts longer), hard to extinguish

      • Partial-Reinforcement Extinction Effect: tendency of behavior learned through partial reinforcement (think variable) to last longer & be harder to extinguish

• Dopamine Activity Underlies Rewards

  • Dopamine = important component of neural reward system

  • Dopamine release sets reward value of:

    • unconditioned stimulus (Classical conditioning)

    • Reinforcer (operant conditioning)

  • Drugs that block dopamine block conditioning

  • The more deprived you are, the more rewarding/more dopamine released in pursuit of thing that removed deprivation

    • Ex: the greater the hunger, the greater the dopamine release when you do finally eat

    • More dopamine is released under conditions of deprivation compared to released under no deprivation

    • Ex: catfish

  • Robinson & Berridge: there’s a difference between wanting something and liking something, introduced the distinction between the wanting and liking of a reward

    • Dopamine plays a role in the WANTING

• Phobias & Anxiety

  • Phobia: an acquired fear that is out of proportion to real-life threat

  • People can LEARN fears through conditioning, a phobia can be CREATED

    • Infamous example: John Watson (Behaviorist) & Rosalynd Raynor, “Little Albert”, CLASSICAL CONDITIONING

      • Created fear with a loud jarring sound & white rat, white rat alone can stimulate fear responses, made him fear other fluffy things, too

  • Someone can have a bad experience that contributes to them developing a phobia, or a phobia can simply be created/fall out of the sky

  • Relief of avoidance/engaging in rituals can actually reinforce anxious & obsessive thoughts

  • Instead, exposure therapy is recommended

  • Exposure therapy: based on idea that exposure to a fearful stimulant in a safe, therapeutic environment may effectively treat phobias

  • Drug Addiction: 

    • Accessories used for drug addiction can be a conditioned stimulus (CS)

    • Cues associated w/ drugs can trigger cravings & tolerance

    • People can be conditioned & develop tolerance in specific contexts/settings

      • Ex: a diff location can prompt a diff response b/c you usually have drugs in a certain environment

  • Learned Helplessness: learning that you don’t have control of your environment

    • Ex: some dogs didn’t even try to go through the wall, they just took the shocks one after another

    • Related to depression

• Social learning: 

  • Modeling: copying/imitating a behavior you see in others

  • Vicarious/Observational (“Social Cognitive Learning”) learning: seeing what someone else does & thinking about the consequences, learning to engage in a behavior or not to engage in a behavior after seeing others being rewarded/punished for performing that action

    • Ex: Albert Bandura 1970s

    • We don’t have to learn by classical & operant conditioning completely

    • Bobo experiment: kids watched a grownup play w/ Bobo doll more violently, are they going to play with it more violently too?, answer: YES

    • RESULT: kids showed observational learning/vicarious learning

    • Ex: Tiktok challenges

    • What determines whether vicarious/observational learning will occur?

      • Attention: observe model’s behavior & consequences

      • Retention: you need to remember what they did to copy it

      • Reproduction: you have to be able to convert memory into overt behavior, have to be able to carry out

      • Motivation/Incentive: you have to have some motivation to reproduce a response, you have to believe that it will benefit you

        • Ex: motivation for speeding b/c good things happen to her dad while speeding vs bad things happen to her dad while speeding

Essay Q: Observational learning- what leads someone to this?

• Instructed Learning: an extension of social learning, learning associations and behavior through verbal communications

  • Plays a key role in development

Chapter 5- Sensation and Perception

5.1 Sensory Information is Translated into meaningful signals

• We see, hear, taste, smell, feel from touch results from brain processes that ACTIVELY CONSTRUCT perceptual experiences from sensual information

• Sensation = detection of physical stimuli and transmission of that information to brain

  • Ex of physical stimuli: light/sound waves, molecules food, odor, temperature, pressure changes

  • Essence = DETECTION

• Perception = brain’s further processing, organization, and interpretation of sensory information

  • Results in our conscious experience of the world

  • Essence = construction of useful and meaningful information, kind of like interpretation

    • What can we make sense of this signal? 

    • Ex: associating the sensations (the smell, tingly feeling, sharp taste) of being splashed in the face while taking a sip with root beer

• Sensation & Perception are integrated into experience, but at the same time experience guides perception! (two-way street)

  • Bottom up processing: based on the physical features of the stimulus

    • Ex: recognizing the splash of root beer based in scent, moisture, taste

  • Top down processing: how our knowledge, expectations, or past experiences shape our interpretation of sensory information

    • Context impacts perception

    • This means that what we EXPECT to see influences what we PERCEIVE

    • Ex: we expect an apple to be red and apple-shaped, so when we are unlikely to see a blue, apple-shaped object as a real apple

    • What makes proofreading our own work so difficult

• Transduction: the translation of stimuli by sensory receptors into neural signals so that they can be interpreted/processed by the brain

  • The brain cannot process the physical stimuli directly, so stimuli have to be TRANSLATED into signals that the brain can interpret

    • Involves specialized cells called sensory receptors

    • Sensory receptors receive stimulation (either chemical or physical) 

    • Chemical stimuli: taste & smell

    • Physical: vision, hearing, touch 

  • Each sense organ contains specialized receptors that detect specific types of stimuli

• Brain requires qualitative and quantitative information about a stimulus to function effectively

  • Qualitative information: most basic qualities of a stimulus

    • Difference between a flute’s sound and a tuba’s honk

    • Sweet vs. Salty

    • Ex: traffic light is green

    • Different sensory receptors respond to different qualitative stimuli

  • Quantitative information: degree/magnitude of those qualities

    • Like their intensity

    • Ex: how loud the tuba’s honk is, how salty the pasta is

    • Ex: traffic light is extremely bright/ phone brightness is really high 

    • Depend on the RATE of the neuron’s firing and/or HOW many neurons are firing

5.2 Detection Requires a Certain Amount of Stimulus

• Sensory organs are constantly acquiring info. From environment

  • But you don’t notice it until it surpasses a certain threshold

  • Absolute threshold: minimum intensity of stimulation that MUST occur before you experience a sensation

    • Stimulus intensity you would detect 50% of the time

    • Ex: how loudly will someone in the next room have to whisper for you to hear it?

      • Absolute threshold: quietest whisper you could hear 50% of the time

  • Difference threshold (“just noticeable difference”): SMALLEST difference between 2 stimuli that you can notice

    • Ex: commercial being louder than the TV show

    • Weber’s Law: states that the just noticeable difference between 2 stimuli is based on a proportion of the original stimulus rather than on a fixed amt. Of difference

      • More intense stimuli require bigger changes for you to notices

        • Ex: 5 lb package vs 5 lb + 1 oz. package will be difficult to notice the difference 

• Signal Detection Theory (SDT): states that detecting a stimulus is not an objective process, instead is it's a subjective decision with 2 components

  • Sensitivity to stimulus in presence of “noise”

  • Sensitivity = determined by what your senses can detect

  • Criteria used to make the judgement from ambiguous information 

  • Objective implies that the process isn’t influenced by personal feelings/opinions

    • Ex: Radiologist looking for a faint-shadow on an x-ray that might signal an early-stage cancer, this is a subjective decision b/c their judgement can be influenced by medical training, experience, motivation, attention, awareness of consequences, etc.

• Response bias: participant’s tendency to report/not report detecting the signal in an ambiguous trial

  • Participant may be strongly biased against responding and need a great deal or a small amount of evidence that the signal is present

  • Ex of radiologist: possibility of causing painful & unnecessary treatment may bias radiologist to not report the signal, but possibility of missing a potentially deadly fast-growing cancer may cause the radiologist to diagnose the cancer w/ weak x-ray evidence (yes, cancer is present)

  • Response bias = tendency that can be biased/pushed around depending on consequences of decision 

• Sensory adaptation = decrease in sensitivity to a constant level of stimulation

  • Ex: becoming “nose-blind” to cat’s smell as a cat-owner

5.3 The Brain Constructs a Stable Representation of the World from the Five Senses

• Sometimes our perception of one's sense is influenced by input from another sense

  • Ex: biting into an orange and expecting smell/taste/sound but instead tasting a lime

  • Ex: cinnamon flavored watermelon-looking ice cream cake

• Synesthesia: unusual combinations of sensations (like hearing the taste of food)

  • Ex: bill hates driving because the sight of road signs tastes like a mixture of pistachio ice cream and earwax

  • Ex: sounds are color

5.4 Sensory Receptors in the Eye Transmit Visual Information to the brain 

• Light passes through the cornea (eye’s thick, transparent outer layer)

• Cornea focuses the incoming light

• Light enters lens

• Light is bent further inward & focused to form an image in retina (thin inner surface in back of eyeball)

• Retina: thin inner surface of back of eyeball which contains the sensory receptors that transduce light into neural signals

  • Retina contains sensory receptors that transduce light into neural signals

• Pupil is dark circle @ center of the eye, small opening in front of the lens

  • Contracting = closing

  • Dilating = opening

  • Controls how much light enters eye

• Iris determines eye color & controls pupil size

• Accommodation: muscles behind the irs change shape of lens

  • Flattening = focus on distant objects

  • Thickening = focus on closer objects

  • Presbyopia = difficulty focusing on closer objects, increases w/ age

    • That’s why people over 40 need reading glasses

• Retina has 2 types of receptor cells: Rods & Cones

  • Rods = retinal cells that respond at extremely low levels of light and result in black and white perception, responsible for night vision

    • Poor @ fine detail, don’t support color vision

    • Why everything is gray on a moonless night

    • Also why it’s hard to read in the dark

    • Approx. 120 million rods in retina

  • Cones (Cones for COLOR)= retinal cells that respond to higher levels of light and result in color perception

    • Approx 6 million cones in retina

    • Densely packed in fovea

    • Become increasingly scarce toward the outside edge of the retina

  • Fovea = center of retina where cones are densely packed

• Transmission from eye to brain

  • Sensory receptors in the retina generate electrical signals

    • These sensory receptors contain photopigments

    • Photopigments: protein molecules that become unstable and split apart when exposed to light

    • This splitting/decomposition alteres mem. Potential of the photoreceptors, triggering action potentials in downstream neurons

    • Other cells in middle layer of retina perform computations

    • Ganglion cells = first neurons in visual pathway, first neurons to generate action potentials in seeing

    • Ganglion cells send signals along axons from inside eye →thalamus

      • Axons gathered into a bundled into optic nerve

      • Optic nerve exits retina

        • Point where optic nerve exits retina = blind spot

    •  half of the axons in the nerves cross Optic chiasm 

      • Causes info from left visual space to be projected to right hemisphere of brain & right visual field to be projected to left hemisphere of brain

    • Primary visual cortex: cortical areas in occipital lobes at back of head

• “What” and “Where” pathways

  • Theory: visual areas beyond primary visual cortex form 2 parallel processing streams

  • Ventral stream: specialized for perception & recognition of objects (WHAT)

    • Projects from occipital lobe → temporal lobe

    • Ex: determining color & shape

    • Object agnosia = inability to recognize objects

  • Dorsal stream: specialized for spatial perception, determining WHERE an object is and relating it to other objects in the scene, (WHERE)

    • Projects from occipital lobe → parietal lobe

• Trichromatic Theory: color vision results from activity in 3 types of cones that are sensitive to different wavelengths of light

  • Sensitive to short wavelengths: blue-violet light (S)

  • Sensitive to medium wavelengths: yellow-green light (M)

  • Sensitive to long wavelengths: red-orange light (L)

• Color blindness= having partial blindness for certain colors

• Opponent Process Theory: describes the second stage in visual processing

  • Red and green are opponent colors

  • Blue and yellow are opponent colors

  • Ex: afterimages

• Lightness = color’s perceived intensity

5.6 Perceiving Objects Requires Organization of Visual Information

• Gestalt principles

  • Proximity: the closer 2 figures to each other, the more likely we are to group them and see them as part of the same object

  • Similarity: We tend to group figures according to how closely they resemble each other (whether that be in shape, color, or orientation)

  • Good Continuation: we tend to group together edges or contours that are smooth and continuous as opposed to having abrupt/sharp edges

  • Closure: we tend to complete figures that have gaps

  • Common fate: we tend to see things that move together as belonging to the same group

• Object Constancy: correctly perceiving objects as constant in their shape, size, color and lightness despite raw sensory data that could mislead perception

  •  idea that leads us to perceive the object as static/unchanging despite changes in the sensory data that compose the object

  • Ex: image in ,mirror is much smaller than parts of you being reflected

    • Size constancy: requires knowing how far away an object is 

    • Shape constancy: requires knowing what angle(s) we are seeing the object from

    • Color constancy: requires comparing the wavelengths of light reflected from the object with those reflected from its background

    • Lightness constancy: requires knowing how much light is reflected from object & its background

  • Perceptual systems are tuned to detect changes from baseline conditions

• Facial Perception

  • Any pattern in the world that has facelike qualities will look like a face

  • Humans = highly social animals, therefore able to notice the subtle differences in facial features that make individuals unique & slight different configurations of features to convey facial expressions

    • Person’s mood, attentiveness, sex, race, age, etc. by looking @ person’s face

    • Prosopagnosia: deficits in ability recognize faces (but not objects)

      • People w/ prosopagnosia cannot tell one face from another but can still recognize whether or not it is a face and whether or not its upside down

        • Can be from birth/genetic factors

        • Developmental or from injury

    • People struggle to recognize faces, especially known, that are inverted/upside down

5.7 Are Faces Special?

• Faces aren’t special b/c they’re faces, but b/c they are objects w/ special properties

• Expertise hypothesis: suggests that faces are only special b/c they are objects with certain properties that we interact with extensively

• Proponents of expertise hypothesis can apply to other objects/people

  • Ex: bird expert

5.8 Perception of Depth, Size, and Motion is Guided by Internal and External Cues

• Depth Perception:

  • We can distinguish between 2D and 3D b/c they have diff. Depth cues

  • Bino(TWO eyes)cular depth cues: available from both eyes and are only present when viewing 3D world

  • Convergence: type of binocular depth cue that refers to the way the eye muscles turn the eyes inward when we view nearby objects

    • Ex: to focus on a closer object requires eyes to converge more than if the object is farther away

    • Brain uses info. From how much eyes are converging through feedback from muscles to perceive distance

    • Ex: looking at eraser cap right in front of face to do a cross-eyed trick and show friends in elementary school

  • Mono(ONE eye)cular/Pictorial depth cues: available from each eye alone, provide organizational info used to infer depth

    • Occlusion: a near object occludes or blocks an object that is farther away

    • Relative size: far-off objects project a smaller retinal image than close objects do, assuming that the far-off and close objects are the same physical size

      • Ex: man in chair and other man in background, man in background appears smaller b/c he’s farther away than the man in chair

    • Familiar size: because we know how large familiar objects are, we can tell how far away they are due to retinal images

    • Linear perspective: seemingly parallel lines appear to meet/converge in the distance

    • Texture gradient: as a uniformly textured surface recedes, its texture continuously becomes denser

    • Position relative to horizon: All else being equal, things below horizon that look higher in visual field are perceived as farther away while objects above horizon that appear lower in visual field are perceived as as being farther away

    • Motion Parallax:  monocular depth cue observed when moving relative to objects, where objects that are closer appear to move faster than the objects farther away

      • Ex: birdie vs plane

      • arises from the relative speed with which objects move across the retina as a person moves

  • Motion depth cues: emerge when we move through space & depend on relative changes to visual input w/ motion

  • Binocular/Retinal Disparity: a depth cue caused by distance between a human’s 2 eyes, each eye receives a slightly different retinal image

    • Reason why when you look@ something w/ one eye closed and then switch them it looks like it moved

    • One of the most important cues to depth perception!

  • Stereoscopic vision: ability to determine an object’s depth based on that object’s projections to each eye

• Size Perception:

  • Distance matters: size of an object’s retinal image depends on the object’s distance from the observer

    • Farther the object, the smaller its retinal image

    • Size perception sometimes fails!

  • Optical illusions that result in errors in size estimates when normal perceptual processes incorrectly represent distance between viewer & stimuli

• Motion Perception: brain uses several causes to detect motion

  • When our head is still and our eyes move as we stay focused on an object

  • Stroboscopic movement: perception illusion that occurs when 2+ slightly different images are presented in rapid succession

    • Motion illusion b/c brain fills in gaps

    • Movies are made of still-frame images

  • Motion aftereffects: provide evidence that motion-sensitive neurons exist in the brain

    • Occur when you gaze @ a moving image for a long time end then look at stationary scene & experience a momentary impression that the new scene is moving in the opposite direction from the image

      • Direction-specific neurons begin to adapt to motion, become fatigued & less sensitive

      • Stimulus is suddenly removed, motion detectors that respond to all other directions are now more active than fatigued motion detectors

5.9 Audition Results from Changes in Air Pressure

• Audition is second to vision as a source of info. About the world

• Audition: hearing, the sense of sound perception

• Hearing begins w/ movements and vibrations of objects that can cause the displacement of air molecules → Displaced air molecules make change in air pressure → change travels through air 

• Sound wave: pattern of the changes in air pressure over time, produces perception of a sound

  • Amplitude: determines loudness of sound

    • High amplitude = loud sound

    • Low amplitude = soft sound

  • Frequency: determines pitch of sound, measured in Hz

    • Low frequency = low-pitched

    • High frequency sound = high-pitched sound

• Sound waves arrive @ outer ear → travel down auditory canal to eardrum (beg. Of middle ear) → eardrum vibrates → vibrations transferred to ossicles → ossicles transfer eardrum’s vibrations to the oval window (within cochlea & inner ear) → oval window’s vibrations create pressure waves in cochlear fluid → prompts basilar membrane to oscillate → movement of basilar membrane stimulates hair cells to bend & send info to auditory nerve → auditory neurons in thalamus extend axons to primary auditory cortex (in temporal lobe)

  • Eardrum/Tympanic Membrane: thin membrane that marks the beginning of the middle ear, sound waves cause it to vibrate

  • Ossicles: 3 tiny bones (Hammer, anvil, stirrup) 

  • Oval window: membrane located within cochlea in inner ear

  • Cochlea: fluid-filled tube that curls into snail-like shape, contains basilar membrane

  • Basilar membrane: runs through center of cochlea

  • Hair cells:  primary auditory receptors

• Vestibular system: relies on ears to maintain balance

  • Vestibular sense: perception of balance determined by receptors in inner ear, uses info from receptors in the semicircular canals of inner ear

  • Canals have liquid that moves when head moves, bending hair cells at ends of canal → bending generates nerve impulses that inform of head’s rotation 

  • Explains why inner ear infections or standing up too quickly can make us dizzy

  • Ex: seasick, carsick 

    • Conflicting signals arriving from visual & vestibular systems

• Cochlear Implants: small electronic devices that help provide sense of sound to a person who has a severe hearing impairment

  • First successful neural implant in humans

  • Helps people w/ hearing loss due to loss of hair cells in inner ear

  • Directly stimulates auditory nerve rather than amplifying sound (hearing aid)

  • Concerns about it affecting deaf culture

5.10 Pitch is Encoded by Frequency and Location

• Pitch is encoded via 2 mechanisms:

  • Temporal Coding: mechanism used to encode relatively low frequencies where firing rates of cochlear hair cells match frequency of sound wave, can only do high frequencies if diff. Groups of cells take turns firing (volleys)

    • Firing rates of cochlear hair cells match the frequency of the pressure wave

    • Ex: sound of a tuba

  • Place Coding: mechanism where the frequency of a sound wave is encoded by the location of the hair cells along the basilar membrane

    • Diff. frequencies activate receptors @ diff LOCATIONS

    • Higher frequencies vibrate better @ base, lower frequencies vibrate better toward tip of basilar membrane (inside cochlea)

      • Hair cells @ base of cochlea are activated by high frequency sounds, hair cells @ tip of cochlea are activated by low frequency sounds

      • Therefore, frequency of sound waves is encoded by receptors on the area of the basilar mem. That vibrates the MOST

• Sound Localization:

  • Locating origin of sound is important, but sensory receptors can’t code WHERE events occur

  • Instead, brain integrates sensory information coming from each ear

  • Ex: sound reaches right ear first b/c phone is closer to right side of body

  • Ex: barn owls

5.11 Are Your Listening Habits Damaging Your Hearing?

• Blasting music is a known cause of hearing loss

• Exposure to music typically occurs over long periods of time, falls into second category of risk

• Loud sounds can lead to hearing loss by permanently damaging hair cells in inner ear

• If others need to shout, if you can’t hear ppl @ shoulder length or if you can hear the music when it’s off ears, it’s TOO LOUD

5.12 There Are Five Basic Taste Sensations

• Taste and Smell are both chemical in nature but they are distinct senses w/ diff. Processes

• Gustation: sense of taste

• Olfaction: sense of smell

• 5 basic taste sensations:

  • Taste Buds: sensory organs in the mouth that contain taste receptors

  • Papillae: sensory organs on the tongue, mouth, and throat

  • Food/Fluid/other substances stimulate taste buds → signals to thalamus → signals are routed to insula & frontal lobe → experience of taste is produced

  • Every taste is composed of:

    • Sweet

    • Sour

    • Salty

    • Bitter

    • Umami (savory/yummy)

  • Taste relies heavily on sense of smell, that’s why food sucks when you’re congested

  • Taste also relies on texture and discomfort

  • Brain integrates various signals to make entire taste

  • Supertasters: people who experience especially intense taste sensations, are highly aware of flavors and textures, usually have more tastebuds than others (35+)

    • Most likely women

    • Taster status is a function of age, people lose half their taste receptors by age 20

    • More likely to feel pain when eating very spicy foods

    • 35+ taste buds

  • Cultural influences can influence food preferences and perception

    • Begins in womb

5.13 Smell is the Detection of Odorants

• Odorants: chemical particles

• Odorants pass into the nose → sniff into nasal cavity upper and back portions → warm & moist environment helps odorant molecules come in contact with olfactory epithelium → odorant stimulates diff. Types of receptors → activation pattern across these receptors determines olfactory perception → smell receptors transmit info. DIRECTLY into olfactory bulb (NOT thalamus)→ scent goes into other areas (ex: prefrontal cortex processes whether the smell is pleasant or unpleasant)

  • Specificity of receptors & pattern of receptor responses result in sensation and perception

  • Olfactory epithelium: thin layer of tissue within nasal cavity that has thousands of smell receptors embedded in it

  • Olfactory bulb: brain’s center for sense of smell, located just below frontal lobes

  • Prefrontal cortex processes whether smell is pleasant or unpleasant

• Pheromones: chemicals released by animals that trigger physiological or behavioral reactions in other animals & insects

  • Don’t elicit conscious smells

  • Processed similarly to olfactory stimuli

  • Specialized receptors in nasal cavity respond to presence of pheromones

5.14 The Skin Contains Sensory Receptors for Touch

• Haptic sense: sense of touch, conveys sensations of temperature, pressure, and pain

• First sense to develop in fetus

• Tactile stimulation: gives rise to experience of touch, anything that makes contact with out skin gives us this

• Sensing temperature: receptors for warmth & receptors for cold

  • Simultaneous activation can produce strange sensations

• Touch info. Travels to thalamus → thalamus sends it to primary somatosensory cortex in parietal lobe 

• Why you can’t tickle yourself: brain responds less to tactile sensations that are self-produced compared to those externally generated

5.15 Pain Receptors Exist Throughout the body

• Actual experience of pain is created by the brain

• Most experiences of pain happen b/c of damage to skin activates haptic receptors

• Nerve fibers convey pain are thinner than others, and are found in all body tissues that sense pain

  • Joints, bones, muscles, organs, etc.

• 2 kinds of nerve fibers for pain:

  • Fast fibers: sense sharp, immediate pain, myelinated axons (send info quickly), activated by extremes in physical pressure & temperature

    • Ex: touching a hot skillet

    • Fast-acting receptors are activated by strong physical pressure & temperature extremes

  • Slow fibers: sense chronic, dull, steady pain, unmyelinated axons (send info slowly), activated by chemical changes in tissue when skin is damaged

• Gate Control Theory: we experience pain when pain receptors are activated and a neural “gate” in spinal cord allows signals into brain, pain signals are transmitted by small diameter nerve fibers that can be blocked @ spinal cord by firing of larger sensory nerve fibers/info abt. Touch is transmitted (ex: by rubbing a sore arm)

  • You can’t experience pain if gate is closed

  • Sensory nerve fibers can “close a gate” and prevent/reduce perception of pain

    • Ex: why scratching an itch is so satisfying

  • Gates can be opened/closed by cognitive states

    • Ex: worrying/focusing on pain seems to open gate wider 

    • Ex: distracting yourself seems to close gate

Quiz 5 corrections: top-down, smell, 

Chapter 6: Learning

6.1 Learning Results from Experience

• Learning: relatively enduring change in behavior resulting from experience

  • Occurs when an animal benefits from experience so that it is better adapted to its environment and more prepared to deal w/ it in the future

    • Ex: being able to better predict when certain events are likely to occur

  • Learning Examines how we adjust our behavior based on the repetition of stimuli/predictive associations between stimuli, actions, consequences

  • Memory: focuses on how we acquire, store, and retrieve knowledge about facts/events/places/skills

• 3 Main types of Learning

  • Nonassociative: learning to adjust responses to a repeated stimulus

    • Simplest form of learning

    • Ex: moving to live by train tracks, train sounds disrupt sleep until you’ve lived in that house for a while

      • Change in response to train stimulus = nonassociative learning

  • Associative: learning about the link/association between 2 stimuli/events that go together

    • Linking of 2 events that generally take place one after the other

    • Develop through conditioning

    • Conditioning: a process in which environmental stimuli & behavioral responses become connected

  • Social: learning by instruction/how others behave, also concerned with understanding how stimuli or events are associated

    • Ex: learning through the media sources about the association between wearing masks and risk of COVID transmission

    • Involves acquiring behaviors and predictive associations between stimuli or events through interactions with others

6.2 Nonassociative Learning Involves Habituation and Sensitization

• Nonassociative: learning to adjust responses to a repeated stimulus

• Habituation: when our behavior response to a stimulus decreases after repeated exposure to stimulus, occurs when stimulus stops providing new information

• Sensitization: when our behavioral response to a stimulus increases after repeated exposure, occurs in cases where increased attention to a stimulus may prove beneficial

6.3 Classical Conditioning Is Learning What Goes Together

• Pavlov’s dogs

• Classical conditioning allows associations to be made between 2 stimuli (ex: the ticking of the metronome and presence of food)

• Classical conditioning: a neutral stimulus stimulus elicit a response because it has become associated with a stimulus that already produces a response

  • Ex: feeling nervous when you see a syringe at the doctor’s office b/c you know that needle & syringe are associated with getting a shot

• Allows organisms to learn that one stimulus predicts the other (metronome predicts food)

• Unconditioned Response: unlearned response, occurs without prior training and is automatic behavior

  • Ex: reflexes, such as salivary reflex

• Unconditioned stimulus: produced unconditioned response

  • Ex: the food

• Conditioned Stimulus (CS): stimulus that organism was conditioned to respond to, ex: metronome was previously unconditioned 

• Conditioned response (CR): Occurs when conditioned Stimulus is presented

6.4 Learning is Acquired and Persists Until Extinction

• Acquisition: the formation of an association between a conditioned stimulus and an unconditioned stimulus (ex: association between metronome and food)

• Extinction: learning that the association no longer exists when the stimuli are no longer paired

• Spontaneous recovery: after a period of time, a previously extinguished conditioned response is once again expressed (“SHE’S BACKKKKK ”)

6.5 Learning Involves Expectancies and Prediction

• Rescorla-Wagner theory: describes how the strength of the association between 2 stimuli depends on how unexpected or surprising the unconditioned stimulus is

  • Positive prediction error: error that results when an UNexpected stimulus is PRESENTED

  • Negative prediction error: error that results when an expected stimulus is MISSING