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NYU / Psychology / PSY 101 / What is Sensory receptors?

What is Sensory receptors?

What is Sensory receptors?

Description

Chapters 5-8


What is Sensory receptors?



Overview:

● Chapter 5:

○ Sensation and perception

● Chapter 6:

○ Learning

● Chapter 7:

○ Memory

● Chapter 8:

○ Thinking, Language and Intelligence

Study Guide:

Chapter 5: Sensation and Perception:

● Stimuli types:

○ Distal stimulus

■ Object or event located in external world

○ Proximal stimulus

■ Information received by sensory stimuli

● Sensory receptors:

■ Cells specialized to detect certain kinds of proximal stimuli

○ Transduction

■ Process for converting physical stimuli energy into electrochemical

messages for transmission as nerve impulses to the brain

● Basic senses:

○ Sight

○ Hearing

○ Taste

■ Women have more taste buds than men

■ “Super tasters”- some people taste with more intensity than others


What are the Basic senses?



● Ex: some people cannot stand cilantro, it tastes like soap to them

○ Skin senses

○ smell

Principles of Psychophysics:

● Definition: study of the relationship between physical stimulus and sensory experience ● Threshold: level at which one can detect a stimulus or change of stimulus ● Absolute threshold:

○ Lowest level of stimulus intensity at which a sense will respond 50% of the time

● Difference threshold or JND (Just noticeable Difference):

○ Lowest level of change in stimulus intensity at which a sense will respond 50% of the time

● Weber's law: describes detectable change in stimuli

○ Smallest detectable increase in the intensity of a stimulus is a constant proportion of the intensity of the original stimulus

● Fechner’s Law: describes perceived intensity

○ Constant increments in the intensity of the physical stimulus create progressively smaller perceived increases in intensity


What are the Principles of Psychophysics?



● Decision making: signal detection theory

○ Our ability to make decisions about sensory experiences are based on two criterions: If you want to learn more check out math 181 uic
If you want to learn more check out biol 339 class notes
If you want to learn more check out Q: Whenever you have a punishment contingency, what do you need to have in the background?

■ Sensitivity

● How sensitive is the person to incoming signals (how capable are

they of detecting signals from noise)

■ Bias (response bias): how likely the person is to say that they detected or not a signal when the ability is low

● Depends on the benefit or cost of missing or erroneously

identifying a signal

● Vision:

○ Light: electromagnetic energy traveling in waveforms that have an intensity and wavelength

■ Intensity: amount of energy per minute- related to perceived brightness ■ Wavelength: distance in crests between two waves - related to perceived color

○ Anatomy of an eye:

■ Retina

● On back of eye

● Contains photoreceptors

■ Cornea

● transparent outside surface of eye

■ Lens

● Bends light rays passing through it by adjusting shape (with

muscle) . Adjusts shape to focus called “accommodation”

■ Iris

● Circular muscle surrounding papillary opening that contracts or

dilates to control illumination

■ Fovea

● Region of retina that receives input from center of visual field

● Photoreceptors

○ 2 types

■ Rods

● Respond to lower intensities of light (night vision, not color). More

sensitive, but less acuity ( fine detail). Are more prevalent outside

of fovea

■ Cones (3 types) We also discuss several other topics like cantabais

● Respond more to color (not intensity). Less sensitive but more

acuity. More prevalent in fovea

● Neural projections of photoreceptor

○ Bipolar cells: receive input from photoreceptors

○ Ganglion cells: receives input from all over retina and converge to form optic nerve

○ Optic nerve: nerve that leaves eye to carry information to the brain

● Principles of sensory reception:

○ Adaptation

■ Gradual decline in reaction to stimulus if stimulus remains unchanged (occurs in all sensory systems) We also discuss several other topics like geol 2020 study guide

● In color vision, sensitivity of cones to certain spectrums becomes

saturated. After effect of staring at one color is a temporary

increased sensitivity to opponent (opposite) color

● Opponent colors:

○ Red-green, blue-yellow

○ Due to ganglion cells that receive input from different type

of cones (wavelengths) and inhibit other ganglion cells

● Contrast: the greater the difference in stimulation, the greater the

sensory effect

○ In brightness contrast, shades will appear lighter or darker

depending on shades of surrounding regions- the result of

lateral inhibition of cells in close proximity of retina

(excitation of one cell, inhibits excitation of a neighboring

cell)

Perception: 

● Problem of perception:

○ Retinas receive a 2d image, how is it transformed to 3d? What are the rules? ○ The world has 3 dimensions (depth) but our retina only has 2

● Binding problem:

○ How are neural representations of light, color edges, movement etc, bound together to form our visual perceptions

○ Put everything together to be interpreted

■ Optical illusions help us know that perception of the world is an

interpretation of incoming sensory information

■ Reveal the automatic and unconscious

● Shepard tables

○ Both tables are the same but with different rotation We also discuss several other topics like group communication involves an unequal number of senders and receivers.

■ Cognitive impenetrability:

● We know they are the same size and shape

but it does not change the way we see them

● Ames room

○ Distance affecting size and perception

● Ponzo illusion

○ Two things equal in length look like they are not (roads for

example, two lines, one far and one close that are actually

the same length)

● Muller Lyer illusion

○ Similar to Pozo (arrows, lines expanding a certain way)

● Form perception: how do we identify objects

○ Figure-ground organization

■ we segregate our visual input into a part that stands out (figure) And the rest (ground)

● Distinguishes objects so that they are seen as a cohesive whole

● Identification of figure vs ground is in the eye of the beholder

● We attend to the figure which results in a finer grain visual

analysis than the background

○ Ink drawings

● Perceptual grouping

○ There are general perceptual tendencies that govern how we group parts to form objects (or whole). These are often referred to as gestalt principles or “laws of perceptual organization”

■ Proximity:

● The closer two objects are, the more likely they are to be grouped together

○ Dots example

■ Similarity:

● Grouping together things that resemble each other

■ Good continuation:

● We prefer contours that continue smoothly along their course

○ Governed by “Principle of Maximum Likelihood” - we know which configurations are likely and which aren’t and this guides us in perception interpretation and grouping

■ Simplicity

● A stimulus pattern will tend to be perceived as simply as possible

■ Common fate

● Elements tend to be grouped by movement or common fate

○ Find the bird example

■ Closure

● We tend to complete or close figures that are incomplete

○ Subjective contours: good continuation, simplicity and closure create illusions of triangles

● Pattern recognition:

○ Combination of data from the incoming information from the outside world (bottom-up or data driven processing) and our knowledge of the world and expectations (top down of knowledge driven processing) combines to help us recognize or identify objects or patterns, place them in space and determine size or shape

■ Example: Ames room

■ Example: context effects- the same perceptual stimulus can be perceived differently based on the context in which it appears

● Perceptual constancy

○ Tendency to perceive objects as being constant in shape, size and lightness/color

■ Shape constancy:

● We perceive the shape of an object more or less the same

independently of the angle from which we view it

■ Lightness and color constancy:

● We perceive the color and lightness of an object to be the same

regardless of variation in an object’s luminance

■ Size constancy:

● We perceive the size of an object as consistent regardless of the

size of the image on our retina (a combination of size of retinal

image and apparent distance)

○ Ex: the blue black or gold white dress (constancy failure)

● Depth perception

○ Binocular clues:

■ Convergence :

● How much must eyes converge to focus on an object - eye

muscles provide feedback

■ Binocular disparity

● Two eyes have slightly different images projected to the retina.

The closer the object, the more different the images to the 2 eyes.

These differences give cue to depth

○ Monocular cues:

■ Interposition:

● Farther away objects will be blocked by view from closer objects

■ Linear perspective and relative size

● Farther away objects produce smaller retinal images

■ Texture gradients

● the texture of pattern of objects changes with relative distance

○ Motion cues:

■ Motion parallax:

● The pattern of movement for objects differs depending on relative distance

■ Optic flow:

● As we move towards an object the pattern of stimulation across

the visual field changes

● Clues to movement perception:

○ Real movement:

■ Retinal image:

● Some cells in visual cortex respond only if object is moving in a

specific direction. These motion selective cells may help us

perceive motion

○ Movement aftereffects due to adaptation of of movement

sensitive cells

■ Eye movements:

● Feedback from the muscles moving our eyes and helps us

determine movement. If an object is stationary but our eye moves,

we don’t perceive movement even though the image moved

across the retina. If an object moves but the retina is stationary,

we perceive motion.

■ Demo:

● Pushing gently on your eyeball. We perceive motion because our

visual system doesn’t know that our eye moved

○ Illusory movement:

■ Apparent motion due to stroboscopic movement:

● If an object jumps from a location to another in the visual field at a

fast enough interval, it appears to be moving

■ Induced motion:

● An object in motion appears to be moving on a static background

(The frame). Motion is perceived by the displacement of an object

(Ex billiard ball) relative to another (ex pool table). How we

interpret movement depends on what we assume is the frame vs

the object in motion ( is the ball or the table moving?). Can lead to

both accurate (ball moving in table) and inaccurate (train station is

moving, not me) movement perception

CHAPTER 6: Learning

learning​ ​:

● Conditioning, principles, caveats and other types of learning

○ Simple learning

■ Habituation:

● Repeated exposure to stimulus- response becomes weakened or

habituated

○ Ex: noise in NYC

● Sensitization:

○ Repeated exposure to stimulus, response becomes

strengthened

■ Ex: somebody’s annoying habits, something

uncomfy in your clothes

○ Classical conditioning terms: (also used in advertising)

■ Unconditioned stimulus (US):

● Stimulus that elicits unconditioned response acts as the reinforcer

○ Ex food

■ Unconditioned Response (UR):

● Response elicited without prior training by US

○ ex salivation, our nervous system

■ Conditioned stimulus (CS):

● Stimulus comes to elicit a new response by virtue of pairing with

the US

○ Ex bell ringing (pavlov)

■ Conditioned response (CR):

● Response elicited by the previously neutral stimulus (CS)as a

result of CS pairing with US

○ Ex salivation

○ Pavlovian conditioning example

■ Dogs and bell ringing

● Classical conditioning stages:

○ Acquisition: CS is paired with UR to produce CR

■ CS is usually the same as US but not always, can also be opposite or compensatory

■ Factors affecting acquisition

● Temporal contiguity of CS and US, best if US onset follows CS

onset

● Proportion of reinforced vs unreinforced trials

● Predictive value of CS

○ Blocking: CS will not be acquired if it does not provide new

information about the likelihood of the occurrence of US

■ You have a bell that precedes food delivery and

you learn to predict it. But now you have a bell and

a light and then food comes. Animals will not learn

that the light also predicts the food, they will ignore

it and stick to only the bell.

■ Assessing strength of of CR

● Response amplitude, how big a CR

● Response probability, how often does a CR occur

● Response latency, when does it occur after CS presentation

■ Extinction:

● CS is presented alone and eventually it no longer elicits the CR

○ Spontaneous recovery:

■ After extinction, a period of time elapses and the CR reappears

■ Second order conditioning:

● When a CS that has acquired CR comes to act as a US

○ For example: presentation of a drug to an addict results in

withdrawal symptoms - drug is paired with place of

purchase,which also comes to produce withdrawal

symptoms and craving

○ Evolutionary significance:

■ Argument against the equipotentiality of CS’s and US’s, not all stimuli are equally likely to be paired

● Example: learned taste aversion- it is very easy to learn to

associate a taste or smell with nausea

○ Ex: terrible bus smell leads to being nauseous upon

smelling something similar to its air freshener

■ Biological preparedness: some stimuli (ex, spiders and snakes) are more readily associated to negative consequences than others (mushrooms and flowers for example). May help explain some phobias

■ Systematic desensitization: common treatment for phobias based on principles of extinction

● Classical vs operant conditioning:

○ Important principle for classical conditioning:

■ For learning to occur, no overt response from subject is required

○ Important principle for operant conditioning:

■ For learning to occur, an overt response needs to be made that can either be rewarded or punished

● Operant (instrumental) conditioning terms:

○ Law of effect:

■ If response is followed by reward, the response is strengthened

■ Response followed by no reward or by punishment, response is

weakened

● Overall, strength of a response is adjusted according to

consequences

○ Stages:

■ Acquisition : response followed by reinforcement (consequence)

■ Extinction: response not followed by reinforcement

● Reinforcement: increases likelihood of a behavior

○ Ex: food, water, cessation of pain

● Punishment: decreases likelihood of behavior

○ Ex: nausea, shock, removal of reward

● Second-order reinforcer (conditioned reinforcers): things that symbolize positive or negative consequences

○ Ex money or grades

■ Shaping: learning a response by rewarding successive approximations to the appropriate responses

● Ex hot and cold game

● Ex, teaching a dolphin slowly to jump for food

■ Avoidance learning to avoid something that predicts a negative outcome (ex dressing warmly in winters or studying hard to avoid a bad grade, principles behind phobias)

○ Factors affecting conditioned response in operant conditioning: ■ No delay in reinforcement is better

■ Schedules of partial reinforcement:

● Fixed interval: reinforcement is given for the first response after a given interval:

○ Example: reinforcement given once every minute if a

response is made

○ Effect: response rate drops after reinforcement, but

increases near the end of the interval

● Variable interval: reinforcement is given for the first response after a predetermined, but variable interval

○ Example: reinforcement is given for first response after a

period of time that varies in between 1 and 3 minutes

○ Effect: response rate is slow, but regular

● Fixed ratio: reinforcement is given after a fixed number of

responses

○ Ex: reinforcement given after 10 responses

○ Effect: response rate is fast and regular

● Variable ratio: reinforcement given after a predetermined, but variable number of responses

○ Ex: reinforcement given after a number of responses that

varies in between 7 and 13

○ Effect: response rate is regular and high

■ Very hard to extinguish responses learned with partial reinforcement, especially with a variable ratio schedule (ex, gambling)

○ Both operant and classical conditioning have stimulus generalization (subjects can respond to similar stimuli like CS or make similar instrumental responses)

and discrimination ( by reinforcement or lack of. The subject can learn to respond to specific stimuli)

■ Anxiety disorders , generalized responses

● Pavlov’s piano example, one note is food but dog will react to

similar notes (not as strongly but there is still a reaction)

○ In classical conditioning, not all CS and US are created equal (equipotentiality principle).

■ In operant conditioning, biological constraints make it easier to pair some responses with some reinforcers rather than others (belongingness

principle)

● Example: teaching a pigeon to flap wings to receive food is hard

● Other types of learning:

○ Observation: learning by watching others who are reinforced

■ Example- modeling- Bandura bobo dolls

● Children watching another child hitting a doll and enjoying it were

more likely to hit the doll themselves

○ Insight: learning non paired or rewarded responses through insight

■ Example, monkey stacking crates to reach banana hanging from ceiling

CHAPTER 7: MEMORY

Memory: 

● Terms:

○ Retention interval:

■ Sensory memory: brief (few seconds only) unlimited capacity sensory memory

● Auditory : echoic

● Visual: iconic

■ Short term memory/working memory brief (15-30 secs),limited capacity memory system encompassing information that is being actively and and consciously processed

■ Long term memory: compilation of information passively stored for long durations, can be accessed by many means

○ Types of information:

■ Episodic memory: memory for events identified by a time and place ■ Semantic memory: for general world knowledge

■ Procedural memory: for skills and procedures

○ Method of retrieval:

■ Explicit memory: (what we usually think of when thinking of “memory”): available to conscious awareness and expressed by recollection. Also called “declarative” memory

■ Implicit memory: not dependent on conscious awareness, expressed by action or reaction

● Stages of memory:

○ Acquisition: information is first encountered- closely linked to attention ■ Encoding: sometimes used to refer to acquisition stage but emphasizes form in which information is processed during acquisition

○ Storage: passive, stage when information is present but it is not being actively encoded or retrieved

■ Often inferred, requires consolidation

■ Memory trace/engram: record/change in nervous system representing storage of information

○ Retrieval:stage where information is remembered/used

■ Common types: recall,cued recall, recognition

■ Other types: motor skill (during bike riding), cognitive skill (while reading or doing other mental activities),conditioned reaction (pavlov’s dogs

salivating when hearing a bell)

● Working memory storage capacity: 7 =- 2 items

○ Chunking: method to increase storage capacity by grouping together discreet items into longer chunks (such as remembering a cell phone number) ○ Duration: 15-30 secs without rehearsal (Brown/Peterson diagram) ● Modal memory model (Atkinson and Shiffrin)

○ Sensory input goes to sensory memory where the unattended information is lost ○ This then goes to the short term memory through attention where the unrehearsed information is lost

○ Through encoding this goes into the long term memory where some information can get lost over time

● Serial position effect (modal memory model):

○ First few and the last items in a list are easier to remember

● Stage theory of memory:

○ Supporting evidence (serial position effect)

■ Primacy effect: we remember stuff at the beginning of a list better than things in the middle of it

● This could be because of rehearsal of the early items (constantly) before the working memory capacity gets full which results on it

being likely to go into the long term memory

■ Recency effect: we remember things at the end of the list better than those in the middle (it was the last thing we saw/heard)

● Could be because items are still in working memory when being

recalled

○ Problems with stage of memory: rehearsal/repetition does not necessarily lead to better long-term storage

● Long term memory : factors affecting storage

○ Organization: we can more easily remember things that are organized in a meaningful way that can be tied back to existing structures

■ Example: mnemonic devices (peg word system)

■ Dual encoding: we remember words that evoke visual images better than those who do not

○ Depth of processing: focusing on meaning of information instead of physical characteristics results in better storage

■ Also called “deep” (semantic) vs “shallow” processing

● Example: does the word make sense in a sentence vs how many

times the letter e appears in that word

○ Massed vs distributed practice: we remember things we study slowly over time better than those we study all at once in one short period

■ Example: studying 30 mins daily for a test over two weeks is better than studying 7 hours the night before

○ Emotion: highly emotional material is remembered better and more vividly than non emotional

■ Ex: flashbulb memories (vivid snapshots of when we heard a specific news, such as remembering what we were doing when we heard about 9/11)

● Enhanced vividness does not always reflect accuracy though

○ Types of cues:

■ Recall : few cues - “what do you remember?”

■ Cued recall: few cues: “it began with the letter C”

■ Recognition: more cues: “which one was it”

● Recognition can be more or less difficult depending on similarity of

distractors

○ Encoding specificity:

■ We are more likely to retrieve information in the same environment where it was learned (context acting as a retrieval cue)

○ Search strategies: we can use our knowledge structure to guide out memory search:

■ Example: who is this person- ask yourself: do i know them from college? High school? Work? Etc

● Long term memory: forgetting:

○ Rate of forgetting:

■ The Ebbinghaus forgetting curve: we forget the majority of what was

learned during the first hour and the rate of the rest drops over time

■ Permastore: if we can remember something for 5 years or so, we can most likely remember it forever

○ Interference: information that was learned at one point in time can interfere with our ability to remember information learned at another

■ Proactive interference

● Old information interferes with the new one

■ Retroactive interference

● New information interferes with recalling the old one

○ Accuracy and distortion:

■ Reconstruction: the things we remember are a combination of information present in to-be-remembered event and our world knowledge and

expectations which lead to increased accuracy but also distortion, or

schemas (basic knowledge structures that we tie together with memory

fragments when we are remembering)

● Example of distortion: remembering the office as having books

even though there are none (you associate books with offices)

● we remember items that are not on a list if they fit with the theme

of the rest of the item

Current topics in study of memory:

● Eyewitness identification

○ Many people are convicted because of false eyewitness identification ● False memory

○ Remembering things that did not happen

● Erasing memories (reconsolidation)

○ Concussion

● Repressed memories

○ Infantile amnesia

Brain systems of working and long term memory:

● Working memory: the damage of the frontal lobe can lead to impaired working memory (also decrease in memory span)

● Long term memory: damage to the hippocampus and surrounding structures leads to anterograde amnesia (inability to remember events that happened since the brain injury) ○ Deficit limited to explicit memory which appears relatively normal

○ Commonly damaged in Alzheimer’s disease, Korsakoff’s syndrome (chronic memory disorder from a deficit of thiamine) and brain damage from lack of oxygen

○ Storage in this system takes time (consolidation period) and is temporarily disrupted with a concussion

Implicit (non-conscious memory)

● Relies of several neural systems than explicit memory

○ Amnesics with hippocampal damage are normal on measures of implicit memory ● Types:

○ Conditioned responses

○ Simple skills: motor and cognitive

○ Priming: facilitation in a response based on recent exposure

■ Seeing a word and then being able to solve a word puzzle regarding it, even if you do not recall the word

CHAPTER 8:

THINKING/LANGUAGE/INTELLIGENCE

Mental​ ​Representations: 

● Analogical:

○ They capture some actual, physical characteristics of (And are analogous to) what they represent

■ Ex: a picture in your mind of your mother’s face is analogical, the word “mother” is not

○ Mental images: images of physical stimuli in your mind

■ Example: visual: your mother’s face while auditory: your mother’s voice ○ Mental images have qualities of actual physical stimuli

■ Visual image:

● Mental rotation: our mind rotates and moves mental images as if we were rotating real images ( if it takes longer to rotate the actual physical stimulus to get a particular orientation, it also takes longer to rotate a visual image of that stimulus)

○ Spatial thinking is accomplished with mental maps

■ Can have both picture like (image of a car and spatial relation of parts, mental map of village), and conceptual or symbolic representations (“Canada is north of the United States”)

○ Organization of symbolic knowledge:

■ Concept: a class or category that includes a number of related individuals or subtypes

● Models of category membership:

○ Defining attribute: category membership is determined by a

defining attribute (a musical instrument is a device that

produces music, birds have wings, etc)

○ Prototype: the “Best example” or “average”member of the

category. Within each category, some examples are more

prototypical than others (robin is prototypical, an ostrich is

not)

■ We tend to remember the most typical thing for

every category

○ Exemplar model: the concept is formed by all examples of

the category that you’ve encountered

■ Who is the bachelor?

● All of them, but we lean towards saying the

little boy is more than the adults or we might

think Leonardo Di Caprio is the best

example when thinking of a bachelor in our

mind

● Script of schema: a cognitive structure representing common or likely scenarios. Results in expectations about actions and events. Often used in interpretation of memory and language

○ Example: schema about a picnic- what items are likely to

be there, what events will occur- we immediately think of

sandwiches on a basket when being told somebody was

upset about leaving mustard behind, we do not infer the

basket has tires, or snakes for example.

○ A script is like a schema about a sequence of events.

■ Example: going on a date, going to the movies

● Semantic memory: our large memory store for words and

concepts and associations- thought to be a network of the

associations between concepts

● Problem solving: how do we do complex tasks?

○ Hierarchical approach:

■ Complex problem broken down into subgoals/subproblems

● Example: goal= get to work

○ Subgoal 1: wake up

○ Sg2: wake up

○ Sg3: get dressed, etc

● We tackle these with routines or subroutines

○ Example: going to work in the morning

■ Subroutine 1: turn of alarm and get off bed

■ Sr2: go to bathroom and shower

■ Sr3: put on clothes, etc

■ Skill development: subroutines and subgoals (or units of analysis)

become more complex with practice and help us overcome capacity

limits. oUR Routines as well get “chunked” over time

● Example: beginning typist has subroutines for each letter in a

world while a skilled typist has subroutines for each common word

in a phrase

● Ex 2: beginner football player sees a collection of individual

defenders, skilled player sees a defensive formation

○ Experts: individuals who , through extensive practice, become highly skilled at solving a particular type of problem:

■ Ex: scientist expert in experimental design of a domain

■ Nba player expert at athletic skills regarding basketball

■ Most of us are experts at reading

○ Automaticity: when, through practice, we can perform a task automatically without conscious effort or awareness

■ Ex: automatically reading a string of letters as a word

● Color example too: we see written out colors painted a different

color, if we are asked to say the color it is painted and NOT the

word, it is hard because we automatically read the word even if we

do not want to

■ Nba star automatically putting hand in correct position to shoot

■ Automatically staying within a lane when driving

● Common approaches to problem solving:

○ Mental set: learned way of viewing a problem/task

■ Helpful because similar problems have similar solutions, but sometimes can be hurtful

■ Functional fixedness:

● Tendency to see objects and properties in terms of their most

common use

● Ways to overcome difficulty in problem solving:

○ Working backwards: start with goal and think backwards, think of last step instead of first step

○ Find an appropriate analogy: is there another problem (From a different domain) that had a good solution

○ Use a heuristic: shortcut to solve the problem minimizing cognitive demands ○ Restructure: view problem from a different perspective, remove common constraints-this leads to insight

■ Can occur after incubation period in which problem is ignored

● You think about something so much you get stuck in it, so you let it go for a bit and then you suddenly know the solution

■ Restructuring can form basis for humor

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