Sensation vs Perception

Transduction

Psychophysics: Thresholds, Signal Detection Theory (learn threshold and psychophysics by myself)

Bottom up vs Top down processing 

Attention

Vision

Sensation Vs Perception 

• Sensation 

  • The act of sensing the real world information 

• Perception 

  • the state of being or process of becoming aware of something through the senses.

Perceptions don't always match reality 

Sensation doesn't always match perception 

Illusion 

• The way we perceive a stimulus does not match its physical reality 

Transduction 

• Conversion of an external stimulus into a neural signal 

  • Sensory Receptors: specialized cells designed to convert a certain kind of external information into a neural signal 

Sensory Adaptation

• Sensory neurons adjust their sensitivity based on recent stimulus history 

• Ex. Adjusting to dark vs light conditions

Motion After Effect 

• After Effects are opposing sensory or perceptual distortion that occur after adaptation 

Signal Detection Theory 

• How stimuli are detected under different conditions 

Signal 

• What you are trying to detech 

Noise 

0 similar stimuli that might compete with the signal and interfere with your ability to detect the signal 

Signal to noise ration 

• Difficult of deteching the signal depends on the strength of the signal in relation to the strength of the noise 

Attention

• The input that we receive from the world is overwhelming, in order to process it deeply we must focus on specific parts using attention 

Attention is like a filter because of effects that show reams of information popping through the filter 

• Cocktail party effect 

• - happens when important information pops out in a conversation that you are not attending (ex. Your name)

Inattentional Blindness 

• Occurs when unattended stimuli are ignored as if they weren't there

Charge blindness 

• A version of inattentional blindness that occurs when you fault to detect obvious changes in your environment

Sensation 

• A bottom up process 

Perception 

• Top-down processing which can change what we report about sensations 

Perceptual sets 

• Sets formed when our expectations influence our perceptions

Summary 

What are sensation and perception?

What basic properties apply to all senses?

Transduction

Sensory adaptation

Psychophysics: thresholds, Weber’s law Signal detection

What is the role of attention in perception?

What are top down and bottom up processing?

NEED TO LEARN THESE from Psycho physics 

Psychophysics 

• THe study of how our sensations (psychological events correspond to physical events in the world)

• Absolute threshold 

  • ​​The lowest level of a stimulus needed for the nervous system to detect a change 50% of the time

• Difference threshold 

• Webers law

  • amount of stimulus energy required to produce a JND

  • is a constant fraction of stimulus intensity. (It’s all relative)

Structure of the eye

Sclera 

• The white part 

Pupil 

• Circular hole where light enters

Iris 

• Colored portion of the eye that controls pupil size letting in more or less light 

Cornea 

•  curved transparent layer covering the iris and pupil that helps focus light 

Lens 

• Oval shaped disc that bends light

Accommodation 

• Changing of the lens’ shape to focus on near/far objects

If your eye is too long 

• Myopia (nearsightedness)

• Hyperopia (farsightedness)

Retina 

• Membrane at the back of the eye responsible for converting light into a neural signal 

  • Fovea

    • Central portion of the retina responsible for visual acuity, has a high density of cones

  • Acuity 

    • Sharpness of vision 

  • Retina 

    • Fovea is very small (takes up 1% of retina size) highly represented in the brain (gives us that acuity) 

  • Saccades 

    •  small jerky movements of the eye allowing for rapid changes of focus 

    • Goal: put the fovea on a new location 

• Structure of the retina 

  • Rods 

    • Respond under low levels of light

    • Not color sensitive 

    • More common outside of fovea

  • Cones

    • Sensitive to fine detail 

    • Primary located in fovea

    • Color sensitive 

    • Less plentiful than rods

  • Optic nerve

    • Bundle of axons that travels from the reina to the brain 

  • Blind spot 

    • Area of the retina where the optic nerve exits the eye (this is covered though by the other eye vision that brain uses to make a vision) 

Color perception 

• When light hits and object, some is absorbed and some is reflected 

  • We perceive reflected light as color (white objects reflect all light while black reflect no light)

• Hue

  • The color of light corresponds to wavelength 

Higher wavelight 

• Low frequency 

• Low energy

Lower wavelength 

• High frequency 

• High energy 

Trichromatic theory 

• Color vision is based on three primary colors (Blue, green, and red)

  • This is because we have 3 types of cones (one that like blue, one likes red, one likes green wavelengths)

Opponent Process theory 

• We perceive colors in terms of three pairs of opponent colors

  • Red-green

  • Blue-yellow

  • Black-white

Visual system uses principles of both trichromatic theory and opponent process theory at different stages of color processing 

Depth 

The world is 3D but on retina the image is 2D

Sensation is 2D but perception (post processing in your brain) is 3D

Multiple objects in the 3D world could cause the same 2D retinal image (as far as retina is concerned)

Depth Perception 

• Ability to judge distance and spatial relations 

Depends on 

• Binocular depth cues (involve both eyes)

• Monocular depth cues (involve one eye)

Binocular Depth Cues

• Binocular Disparity

• Each eye sees slightly different mages; brain can judge depth 

• Convergence 

  • Eyes converge to see near objects (closer eyes come to being rotated fully inward the closer the object you are focusing on will be)

Visual Perception

• Monocular Depth Cues

  • Relative Size (Distant objects look smaller than closer objects)

• Texture gradient 

  • Texture is more clear on closer objects

• Interposition 

  • Closer objects appear in front of distant objects

• Linear Perspective

  • Parallel lines converge with distance

• Height in plane 

  • Distant objects appear higher than closer objects

• Light and Shadow

  • Shadows can tell us about form 

• Motion parallax 

  • Closer objects pass more quickly than distant objects

Mueller-Liter Illusion (Two lines are the same)

Ebbinghaus Illusion (Two dots are the same)

Summary 

• Perceiving depth is a hard problem because the information from the retina does not directly specify depth 

• The brain puts together information from multiple cues, and makes its best guesses arrive at a 3D representation of the world

Perceptual Constancy 

• We perceive objects as constant despite change in sensations that arise from those objects 

Shape constancy 

• Perceived shape is constant, even though shape of the image (on retina) varies

Color Constancy - Perceive stimuli as consistent across varied conditions 

-

• Size constancy

  • Perceive stimuli as consistent across varied conditions 

Summary 

Sensation 

• Detecting stimulus energies (through transduction)

(Psychophysics, absolute thresholds, signal detection theory)

Perception 

• Building representations of the world 

  • Attention 

  • Top-down processing

  • Structure of the visual system

  • Depth perception

    • Using multiple cues to detect the 3D world

  • Color Perception

    • Trichromatic and opponent process theories 

  • Perceptual constancies 

    • Shape, color, size

Gestalt Principles of Perceptual Grouping 

Figure-Ground separation 

• Your visual system automatically tries to identify figure

• FIgures are integrated units of perception 

• Lots of cues converge to give us Figure (motion depth, patterns, and even some in 2D)

Gestalt Psychologists 

• Identified grouping principles we use to identify figures

Gestalt Principles 

• Rules that govern how we perceive objects as wholes within their overall content

Common Fate 

• Objects moving at the same direction and at the same speed are perceived as a group 

  • Geese flying in a “V”

  • People doing the wave at a stadium

Synchrony 

• Stimuli that are perceived to occur at the same time are perceived as part of the same event 

  • I drop my keys and a sound occurs at the instant you see them hit floor

Summary 

• Your brain does a lot of complex processing in order to perceive objects and depth in the world 

• Constructs 3D interpretations from 2D retinal images 

• Maintains object, shape and size constancy, in spite of variations in retinal image 

• Separates figure and ground 

Audition 

• Sound 

  • Vibration; mechanical energy that travels through some medium (air, water, …)

    • Without a medium there is no sound 

• Sound is derived from tiny vibrations

• Compressed & expanded air molecules create waves 

Pitch 

• Frequency of a sound wave (measured in Hz)

• Short wavelength = high frequency = high pitch 

Loudness 

• Height (Amplitude) of a sound wave (measured in dB)

  • Larger amplitude = louder

  • Risk hearing loss from long exposure to sounds over 100 dB (start to feel pain for sounders over 125dB)

Timbre

• Quality of complexity of a sound 

  • Reason different musical instruments sound different when playing the same note

Structure of the ear 

• Outer 

  • Funnels sound to the eardrum 

• Pinna

• Ear Canal 

• Ear drum

• Middle ear 

  • Transmits sounds from ear drum to inner ear

• Ossicles

  • Hammer, anvil, stirrup 

• Inner

  • Transduces sound 

• Cochlea 

  • Transduction accomplished by the movement of the air cells (cilia)

Function of the ear 

• Outer ear funnels sound toward ear drum 

• Eardrum vibrates, moving the ossicles in the middle ear

• Ossicles cause displacements of basilar membrane om the cochlea (inner ear)

• Basilar membrane moves, hair cells bend 

• Excited hair cells cause action potentials 

• Information is sent to brain via auditory nerve 

Pitch perception (high pitches - 5,000 to 20,000 Hz) 

• Place theory 

  • Specific locations on the basilar membrane match tones with specific pitches

    • Base vibrates to high-frequency sounds

    • End vibrates to low-frequency sounds

Pitch Perception (low pitches - up to 100Hz) 

• Frequency Theory 

  • Neuron firing rate matches pitch 

    • Sound frequency corresponds to action potential frequency 

Pitch perception (low pitches - 100 to 5,000 Hz) 

• Volley principle

  • Clusters of nerve cells can fire together (modification of frequency theory) 

Sound localization

• Binaural cues (depending on having 2 ears) 

• Interaural level difference 

  • Sound coming from right side is more intense in right ear because it doesn't have to pass through your head 

• Interaural timing difference 

  • Sound from the right side reaches the right ear first (just a little)

Problems with hearing 

• Conductive deafness 

  • Malfunctioning of the eardrum or ossicles

• Sensorineural hearing loss 

  • Neural signals are not transmitted from cochlea 

• Noise-induced hearing loss

  • Damage to hair cells due to loud noises 

Summary

• Depends on detecting sound waves 

• Range of human hearing about 20 - 20,000 Hz

• The middle ear transmits waves to the inner ear 

• Basilar membrane of cochlea contains receptors (hair cells) 

• Coding of sounds 

  • High frequencies 

    • Location on basilar membrane (place theory) 

  • Mid Frequency 

    • Combination of signals 

  • Low frequencies 

    • Firing in synchrony with the waves (volley theory) 

• Problems with hearing 

  • Sensorineural hearing loss 

    • Loss of sensory receptors 

  • Conduction deafness 

    • Malfunctioning of middle ear 

WEEK 7 - Learning

What is learning 

• Change in an organism's behavior or thoughts as a result of experience 

  • Relatively permanent 

Learning is adaptive 

• Species learn behaviors that aid in survival 

• Allows organisms to adjust their behaviors and responses based on the changing conditions of their environment

Types of learning 

• Non Associative learning (a form of learning that responds to a single stimulus)

  • Habituation 

    • process of responding less strongly over time to repeated stimuli; getting used to a stimulus; usually a neutral stimulus

      • Adaptation of sensory receptors

      • Ex. Background noise at restaurant that you get used to 

      • wearing glasses that feel weird at first but you later adapt 

  • Sensitization

    • Process of responding more strongly over time to repeated stimuli; usually a dangerous or irritating stimulus 

      • Ex. Chinese water torture

      • Sibling pokes you - dont -> quit it -> stop it. -> I WILL MURDER YOU

• Associative learning (occurs when an organism makes connections between 2 or more stimuli/events that occur together in the environment 

  • Classical conditioning

    • Ivan Pavlov, dog digestion work, dog drooling when seeing food 

    • Form of learning in which two stimuli are repeatedly paired 

      • Neutral stimulus + stimulus that elicit an automatic response (reflex)

      • Eventually the neutral stimulus triggered the reflex on its own 

Stimulus types: 

• Unconditioned Stimulus (UCS): Produces a reflexive/automatic response [meat]

• Unconditioned response (UCR): That automatic response (already there, not learned) [salivation]

• Conditioned Stimulus (CS): initially neutral becomes associated with UCS [bell]

• Conditioned Response (CR): Automatic response now triggered by CS [salivation]

Phases 

• Acquisition 

  • Learning phase; when UCS is paired with CS

  • After which CS produces (or acquires) CR

• Extinction 

  • CS appears alone and the CR weakens 

  • CR is eventually eliminated (CR becomes extinct) 

  • Useful for getting rid of an undesired response but doesn't mean forgetting 

• Spontaneous Recovery 

  • Extinct CR suddently emerges again after a delay 

  • Relearning happens more rapidly than initial learning

  • Suggests tjat extinction inhibits rather than erases the learned behavior 

• Renewal effect 

  • Sometimes a response is extinguished when the organism is in different context(s); however, the response may come back when the organism returns to the rogianl setting 

  • Suggests that extinction inhibits rather than erases the learned behavior

• Generalization

  • Respond to stimuli that are similar to the conditioned stimulus

  • Dog salivating to other bell tones 

• Discrimination 

  • Respond to a particular stimulus but not similar stimuli 

  • Don’t respond to stuff that is too different - prevents overgeneralization 

  • Ex. Dog doesn't salivate to sound of gong 

• Blocking 

  • A prior association with a conditioned stimulus prevents learning of an association with another stimulus 

    • Allows us to attend to environmental stimuli in a predictive manner 

• Preparedness 

  • Biological predisposition to learn some associations more quickly than other associations 

  • Ex. phobias of dark/heights/spiders

  • Based on survival value 

• Taste aversion conditioning

  • Associating nausea with food 

  • Help avoid food that has gone bad 

  • Rapid learning of taste aversions is important for survival 

  • Taste aversion conditioning is an example of preparedness

• Fear conditioning

  • Negative associations can be so powerful that they are learned extremely rapidly 

  • Easily generalized to other similar stimuli 

• Chronic drug use 

  • When a drug is used it is associated with the cues present at the time

  • These cues might help predict the drug is coming so the body may prepare itself for the drug which may decrease the impact of the drug on the body 

Factors that influence classical conditioning 

• The intensity of the conditioned stimulus 

  • CS paired with strong UCS, CR will be acquired faster and stronger

• The temporal relationship between the CS and the UCS

  • Conditioning is faster if the CS occurs shortly before the UCS

  • CS should help organism to predict that UCS is coming soon

• How reliably the CS predicts the UCS

  • CS should reliably predict the occurrence of the unconditioned stimulus 

• The number of pairings of the CS and the UCS

  • The greater the number of pairings

Operant conditioning

• Change in voluntary behaviors as a result of the consequences 

• Based on Thorndike’s law of effect: behavior is a function of its consequences 

  • If a certain behavior leads to favorable consequences then more likely to repeat that behavior in the future 

• Learning is controlled by the consequences of the organism’s behavior 

  • Depending on the consequences, the organism either increase or decrease the likelihood of a conscious, voluntary behavior 

• Behavior is now under stimulus control 

  • Stimulus signals the consequence 

    • If you don't stop when you see a red light, you'll get a ticket 

  • Discriminative stimulus

    • Any stimulus that signals the presence of reinforcement

Consequences of behavior 

• Reinforcement 

  • Increased likelihood of of a behavior being repeated 

  • Behavior is strengthened

• Punishment

  • Decreased likelihood of a behavior being repeated 

  • Behavior is weakened

Reinforcement and punishment can be 

• Positive 

  • Add a thing

• Negative 

  • Remove a thing

Positive Reinforcement 

• Ex. Children are given stickers for hard work

  • The addition of a pleasant stimulus reinforces and strengthens the behavior 

Negative reinforcement

• Ex. Leaving the house early to avoid traffic jam

  • The removal of the unpleasant stimulus reinforces the behavior and strengthens it

Positive punishment 

• Ex. getting a speeding ticket

  • The addition of an unpleasant stimulus reduces the likelihood of performing that behavior in the future

Negative punishment 

• Ex. being grounded for staying out too late

  • The removal of a pleasant stimulus reduced the likelihood of performing that behavior in the future 

Extinction 

• Reducing or eliminating a learned behavior by withholding the reinforcing consequences that previously maintained it 

  • Ex. Parent ignoring child's whining where previous they used to get attention during whining 

Spontaneous Recovery 

• The reappearance of a previously extinguished conditioned response after a period of time has passed following extinction 

  • Ex. after parent example parent reverts back to giving attention 

Operant vs Classical conditioning

Classical 

• Automatic behaviors 

• Associate: UCS + CS

• Result: CR

Operant 

• Voluntary behaviors 

• Associate: Behavior + consequence 

• Result: more/less behavior

Operant conditioning requires choice 

• Response requires choosing one behavior over others 

  • Ex. Rat chooses to press the lever instead of sleeping 

  • Different behaviors are associate with their own reinforcers

• Quantitative law of effect 

  • The effects of reinforcing one behavior depend on how much reinforcement is earned for the behavior’s alternatives 

    • Ex. If a pigeon learns that pecking red light will give 2 food and green only gives 1; it will peck the red light 

In real life, classical and operant conditioning occur at the same time 

Reinforcement schedules 

• Continuous 

  • Behavior is rewarded every time it is performed 

    • Faster acquisition 

    • Faster extinction 

    • Ex. Vending machine 

• Partial 

  • Behavior is rewarded only some of the time

    • Slower acquisition

    • Slower extinction

    • Fixed-ratio, variable-ratio, fixed-interval, variable-interval

Fixed Ratio

• A salesperson receiving a bonus for every 5 items sold. 

Variable Ratio 

• Putting money into a slot machine not knowing which spin you will win  

Fixed interval 

• Teacher giving weekly quizzes

Variable interval

• Teacher giving pop quizzes at variable intervals

The amount of time between the behavior and the consequences matters!

• Immediate reinforcement > delayed punishment 

  • Ex. We like to eat candy even though it may give us cavities 

Is reinforcement or punishment better at influencing behavior 

• Punishment may not always be appropriate or productive 

• Children seem to learn better with reinforcement than with punishment 

Problems with punishment 

• Doesn’t teach the targeted behavior, only teaches you what not to do

• Can create anxiety and subversive behavior

• Can model bad/aggressive behaviors 

• May lead to sneaky behaviors to avoid punishment 

Applications of Operant conditioning 

• Training animals is usually done through operant conditioning 

• We can learn good habits by operantly conditioning ourselves 

  • Ex. If you procrastinate you can reinforce studying early by rewarding yourself

• Establishing token economies in clinical settings has been an effective way to encourage good behavior

Observational learning 

• Learning by observing and imitating others 

  • Even infants can do that

  • Ex. observing a chess player to learn the rules 

  • Observational learning is a component of Albert Bandura’s Social Learning Theory 

• Social learning theory 

  • Learning is a cognitive process derived from social observation, and does not necessarily require reinforcement

    • Learning from social models (parents, teachers, other authority figures)

    • Bobo doll study 

According to Bandura, observational learning consists of 4 parts 

1. Attention 

   1. You must pay attention to learn

2. Retention 

   1. You must be able to keep the behavior in your memory 

3. Initiation 

   1. You must be able to execute (or initiate_ the learned behavior 

4. Motivation

   1. You must possess motivation to engage in observational learning

Insight learning 

• Grasping the underlying nature of a problem 

  • Immediate and clear understanding sometimes at the first try - so not through trial and error 

• Aha moment 

  • Get the solution and apply in the future 

• Example

  • Kohler’s study with chimps 

Summary 

• Learning is relatively permanent change in an organism’s behavior or thoughts as a result of experience 

  • Learning is adaptive, it aids survival 

  • Learning is about predicting the future 

  • Most animal species, down to sea anemones, can learn 

• Types of learning 

  • Non associative learning: habituation, sensitization 

  • Associative learning: classical and operant conditioning

  • More complex, cognitive learning: observational and insight learning

WEEK 8 - Memory 

3 stages of memory 

• encoding, storage, and retrieval

Atkinson & Shiffrin model of memory 

• Sensory memory, short term memory, long term memory 

Different types of long term memory 

• Explicit vs implicit memory

Constructive Nature of Memories 

• Misinformation effect, false memories, and schemas

Memory enhancing strategies 

Forgetting 

Eyewitness memory 

7 sins of memory 

What is memory 

• The capacity to store and retrieve information in order to facilitate learning. 

Stages of memory 

•  Encoding

• Getting information into memory 

• Storage 

• Keeping information in memory 

• Retrieval 

• Accessing information from memory 

Encoding 

• Automatic processing 

  • Encoding of details like time, space, frequency, and the meaning of words

    • Remembering the last time you studied for a test 

• Effortful processing 

• Encoding of details that require effort and attention on your part 

  • Remembering the content of what you studied  

• The more meaningful the information is for you, the better it is encoded

• Levels of processing

  • The multiple levels at which encoding can occur, ranging from shallow we deep 

    • Visual (surface) - Acoustic (sound) - Semantic (meaning)

    • Shallow —-------------------------------------------------> Deep

  • If you measure the time for each response, the time is different 

• Self referential encoding

  • Encoding based on an event’s relation to our self-concept

  • Leads to enhanced memory for the event 

Storage 

• Sensory memory 

• Short term memory 

• Long term memory 

3 ways you can retrieve information

• Recall 

  • Free rcall 

    • No cues to aid retrieval 

  • Cued-recall 

    • Retrieval cues that help bring the memories back to mind

• Recognition 

  • Selecting the corect information from an array of options (MCQ)

• Relearning

  • Learning information you previously learned

Influences on Retrieval 

• What happens at encoding can make a memory easier to retrieve later 

• Retrieval is best when it specifically recreates the way information was initially encoded 

Encoding specificity principle 

• Remember best when retrieval condotions match encoding conditions 

• Greater match = better memory 

  • Physical context: context-dependent memory 

  • Physiological state: state-dependent memory 

  • Mood: mood-dependent memory 

• Context-dependent memory

  • Better memory when encoding and retrieval context match 

• State-dependent memory 

  • Better memory when a person is in the same state during both encoding and retrieval 

    • If you study for an exam after a few drinks, you will recall that information better if you are drunk when you take an exam 

• Mood dependent memory 

  • Better memory when a person is in the same mood during both encoding and retrieval 

Atkinson and Shiffrin’s model of memory 

Sensory memory 

• Holds sensory information on the order of milliseconds to seconds 

• Substantial storage capacity, but very limited duration 

• A fleeting sensory memory is made when information is initially processed ny each sensory system 

  • Ear (ionic) lasts < 1 sec

  • Ear (echoic) lasts 5-10 sec

Short term memory 

• Retaining info for a short amount of time (15 to 30 sec) 

• Holds a limited amount of information

• Can be forgotten or transferred to long term memory

• Chunking

  • Organizing information into meaningful chunks

    • Increases short term span 

• Duration 

  • < 30 sec

  • Rehearsal 

    • Maintaining info in STM through mental repetition 

Working memory 

• Holding/manipulating/processing during that short time 

• Actively “working” with

• Enhances the duration of short term memories and facilitates transfer into long-term storage 

  • Phonological loop 

    • Storage of sounds, rehearsal, manipulation of verbal information

  • Visuo-spatial sketchpad

    • Storage of visual information, manipulation of visual images and spatial information 

  • Central executive

    • Acts as attention buffer, decides what gets transferred into the two rehearsal systems

Long term memory 

• Explicit memory 

  • Memories we can recall intentionally; can be stated 

  • declarative memory

    • Ex. What did you do for Halloween last year 

  • Episodic Memory 

    • Recollection of events 

    • Specific experiences 

    • Typically have time and place components 

      • Ex. what you had for lunch yesterday 

  • Semantic memory

    • Recollection of facts

    • general knowledge

• Implicit memory 

  • Memories we can't recall 

  • Nondeclartitive memory 

    • Ex. how to ride a bike

• Procedural memory 

  • Information about the way we do things 

  • You don't think about it, you just do it 

  • We cannot describe them easily 

• Priming 

  • When exposure to one stimulus affects the response to a later stimulus 

• Emotional conditioning 

  • Types of memory involved in classical conditioned emotions responses 

  • These emotional relationships cannot be reported or even recalled, but can we associated with different stimuli 

    • Songs you associate with specific emotional responses 

Reconstructive nature of memories 

• Memory can be surprisingly good and bad 

  • The paradox of memory 

  • Memory is not a recording 

  • Memory is reconstructive

• Misinformation effect

  • Creation of false memories due to misleading information provided after the event

• Fake memories 

  • Recalling an event that did not actually happen or recalling an event differently from the way it happened

Emotional memories 

• Flashbulb memories 

  • Memories for important events might feel different than regular events 

    • Clearer, more vivid, more persistent, exceptionally detailed 

Schemas

• Organized knowledge structure used for understanding and remembering; kind of mental model; framework 

• Schema for what is in a grad student’s office 

  • Computer, papers, books, desk, chair, aura of despair, etc. 

• Can be used to fill in gaps in memory unless more specific information is provided 

  • Remembering what happened in class last week 

  • Remembering last trip to the movies 

• Can be used to generate expectations for what is likely to be true in a situation 

  • Going to a new restaurant 

  • Going to a chain store

Memory Enhancing Strategies

• Chunking

• Rehearsal 

• Elaborative Rehearsal 

  • Think about meaning of information and its relation to other things that are already stored in your memory 

• Mnemonic devices

  • Memory aids that help us organize information for encoding 

    • Ex. PEMDAS

• Self reference effect 

  • Connect the material to other personal information

• Use disturbed practice

  • Spacing effect: the enhanced ability to remember information when encoding is distributed over time 

• Rehearse 

  • Review material over time, in spaced and organized study sessions 

Forgetting 

• Loss of information from long term memory 

• We forget as often as we remember 

  • Encoding failure 

    • Sometimes memory loss happens before the actual memory process begins 

      • Happens bc we do not pay attention to the information in the first place

• Interference created by new information leads to forgetting

  • Proactive

    • When old information interferes with our ability to remember new information 

  • Retroactive 

    • When new information interferes with our ability to remember old information 

• Amnesia 

  • The loss of memory due to brain damage or trauma 

  • Retrograde amnesia 

    • Forget the past but can still form new memories

    • Very uncommon 

    • Recovery of memory (if any) happens very slowly 

  • Anterograde amnesia 

    • Can’t learn new things 

    • Caused by damage to the hippocampus

    • Most common type of amnesia

  • Impairs explicit memory, but not implicit memory!

    • Fear memories stored by the amygdala remain even when explicit memories in the hippocampus are gone 

    • Procedural memory also remains intact in most amnesia patients

• Eyewitness misidentification 

  • Eyewitness memory can be fallible 

  • Mistaken eyewitness identifications contributed to 71% of the wrongful convictions overturned by DNA evidence (innocence project, 2019) 

  • Even worse when 

    • Talked to otherwisenesses (misinformation effect and source confusion) 

    • When the witness is interviewed repeatedly 

    • Situation is stressful 

    • Witness is a child 

7 SIns of memory 

• Transience 

  • Accessibility of memory decreases over time 

    • We forget things that happened a long time ago

• Absentmindedness 

  • Forgetting caused by lapses in attention 

    • Forgetting where you left your phone

• Blocking 

  • Accessibility of information is temporarily blocked 

    • Tip of the tongue

• Misattribution 

  • Source of memory is confused 

    • Who told me that?

• Suggestibility 

  • False memories due to others’ suggestions 

    • A therapist might lead you to believe that you experienced a traumatic event in the past - even though it never happened

• Bias 

  • Memories distorted by current belief system 

    • We tend to remember ourselves in a more positive manner 

• Persistence 

  • Inability to forget undesirable events 

    • You witness a horrific car accident on the way to work and you can't concentrate on work because you keep remembering the scene 

Summary 

• Memory Stages are encoding, storage, and retrieval 

• Atkinson & Shiffrin model categorizes memory into sensory, short term, and long term stages 

• Long term memories can be explicit or implicit 

• Every time we retrieve a memory. We reconstruct that memory 

  • Memory can be distorted by misleading information, false recollections, and schemas

  • Schemas can be useful guides to help us remember things 

• Various strategies can enhance memory 

• Forgetting is the inability to retrieve stored information

• Eyewitness memory is subject to inaccuracies 

• There are memory errors showing how our memories may fail us 

WEEK 10 - Judgement & Decision Making

Bounded Rationality Theory (Simon, 1957)

• We try to make rational decisions but we are limited in some ways 

• Time and cost constraints limit amount of information we have 

• Memory - we can only remember a limited amount of information

Bounded willpower 

• We don't always do what we know best 

Bounded self interest 

• We consider outcomes for others, not just ourselves

Bounded ethically 

• We may not even be aware of ways we violate our own ethics

Bounded awareness 

• We may fail to notice obvious information that is available 

Cognitive Biases (Tversky & Kahneman, 1974)

• We are prone to using heuristics (mental shortcuts) that can lead us astray 

System 1 Thinking 

• Thinking that is fast, intuitive, automatic, implicit, effortless, emotional 

• Involuntary 

• Can’t be turned off 

• Can evaluate only one thing at a time 

• Generates intuitions, feelings, impulsive responses 

System 2 Thinking

• Thinking that is slow, deliberate, effortful, explicit, logical 

• Feels voluntary, involves choice and agency 

• Requires attention 

• Able to follow rules, switch task sets, compare options on multiple attributes

• Make deliberate choice 

System 1 Examples

• This washing machine looks good!

• 2 + 2 = ?

• Understand simple sentences 

• Orient to a sudden sound

• Detect hostility in a voice

System 2 Examples

• Compare 2 washing machines for overall value 

• 645 - 287 = ? in your head 

• Solve a logic puzzle 

• Attend to one voice in a noisy environment

• Figure out why a person might be hostile 

? —--> System 1 (Quick but not necessarily accurate) —-----> System 2 (Kind of lazy requires attention) —-> Wait let's think about that 

Summary 

• Are we rational decision makers

• Do we make optimal decisions given the information we have 

• Bounded rationality 

  • The idea that there are limits on our ability to make rational decisions, such as limited time, memory, willpower, self interest, etc. 

• System 1 vs System 2 Thinking 

  • System 1 Thinking 

    • Quick, intuitive, less accurate 

  • System 2 Thinking

    • Slow, effortful, more accurate 

Biases 

• Ways our reasoning and decision making tends to be systematically distorted 

  • Confirmation bias

  • Overconfidence bias 

  • Anchoring and framing effects 

Heuristics 

• Shortcuts in reasoning that lead to errors 

• Representativeness heuristic 

• Availability heuristic 

Confirmation bias

• Tendency to sek out evidence that supports our beliefs and deny evidence that contradicts them 

Overconfidence effects 

• People think they are better than average 

• People tend to overestimate their abilities 

Framing 

• Being influenced by by the way information is presented (even when the information is the same)

• 5% failure rate of condoms 

• 95% success rate of condoms 

Representative heuristic 

• Judging the probability of an event based on how similar it is to a prototype rather than considering the base rates (how common the characteristics is in the general population)

Availability heuristic

• When asked to judge how likely something is, instead you judge how easy it is to recall it 

• Biases that affect ease of recall

  • How salient?

  • Your personal recent experience

  • How vivid, easy to imagine 

Summary 

• System 1 makes some predictable errors in reasoning and judgment 

• By being aware of these typical mistakes we can avoid them 

  • Biases

    • Confirmation bias

    • Overconfidence bias 

    • Anchoring effects

    • Framing effects

  • Heuristics

    • Representativeness heuristic 

    • Availability heuristic

Intelligence 

• There is no standard definition of intelligence

• Most definitions include

  • Abstract reasoning

    • Ability to understand hypothetical concepts rather than concepts in the here and now

  • Learning 

    • The ability to acquire new knowledge

  • Adapting

    • Adapting to new situations/circumstances

  • Benefiting

    • Benefiting from experience 

What is intelligence? Some cultural differences in everyday views of intelligence (Yang & Sternberg, 1997)

• USA

  • Reasoning well and quickly 

  • Acquiring large amounts of knowledge fast

  • Thinking on one’s feet

• China

  • Wisdom and judgment 

  • Acting for the greater good

  • Humble 

Intelligence is not the same as life achievement or academic success 

Intelligence

• Multifaceted, even experts who study intelligence do not agree on what it is 

Ideas about intelligence

• Spearman’s g 

  • G (general intelligence: hypothetical factor that accounts for overall differences in intellect)

  • S (particular ability in a narrow domain)

• Howard Garner’s Multiple Intelligences

  • There are a lot of options such as linguistics, math, musical, interpersonal, etc. 

• Sternberg’s 3 intelligences

  • Analytical 

  • Practical 

  • Creative 

High correlations among different types of specific intelligences provide some support for g - general intelligence

People also do have specific strengths in specific areas 

Whether intelligence is best thought of a general ability or multiple abilities is debated 

Fluid Intelligence 

• Capacity to learn new ways of solving problems, to “think on your feet”

Crystallized intelligence 

• Ability to use accumulated knowledge of the world to solve problems

Fluid intelligence may “flow” into crystallized intelligence over time

Summary 

• There is no agreed on single definition of intelligence

• Some proposals 

  • G - general intelligence

  • Multiple Intelligences (8)

  • Three intelligences - analytical, practical, creative

• Fluid vs Crystallized intelligence

  • The ability to think quickly and spontaneously vs having acquired knowledge 

Intelligence tests 

• Standardized 

  • Administered in the same way 

• Normed 

  • Constructed so that results are normally distributed with a mean of 100 

The Flynn effect 

• over time, the average score on intelligence tests has increased

History of intelligence testing 

• Francis Galton 

  • Intelligence is a fixed heritable trait associated with sensory processing speed 

  • Coined the term “eugenics”

    • Selective breeding of human populations to improve desired characteristics 

    • Did not apply, just proposed 

• Alfred Binet 

  • Measured intelligence in children in terms of “mental age”

  • Intelligence = mental age/chronological age X 100

  • Used measures of intelligence to help place children in appropriate school settings in the early days of universal public education in France

  • Used measures of intelligence to help place children in appropriate school settings in the early days of universal public education in France

• Lewis Terman 

  • Developed Stanford-Binet test, sympathized with eugenics

  • Wanted to eliminate reproduction of the feeble minded and elimination of an enormous amount of crime,pauperism, and industrial efficiency

  • Worked with US government to develop tests for army recruits, immigrants, and vocational placement  

• It is difficult to avoid cultural bias in constructing intelligence tests 

• Biased tests can lead to biased results 

• Terman’s tests were used to reinforce existing societal prejudices against certain group;s and to support the implementation of racist policies

Intelligence tests were also used in 

• Immigration 

  • Used to identify immigrants who might be mentally defective  

Wechsler Adult intelligence scale 

• 15 subscales 

• Yields 5 scales 

  • Overall IQ

  • Verbal Comprehension 

  • Perceptual reasoning 

  • Working memory 

  • Processing speed 

Is it fair for culture?

• Although improved over early tests, it still depends too heavily on language and cultural knowledge

Summary 

• Intelligence tests are carefully normed and administered in a standardized way 

• The history of intelligence testing has a dark side - culturally biased tests were used to justify discrimination 

• Modern tet attempts to avoid cultural bias 

• The Wechsler Adult Intelligence Test (WAIS) is the most widely used test today 

• It is probably impossible to completely avoid some cultural bias in intelligence tests 

Intelligence Tests predict 

• Health 

• Longevity 

• Cognitive aging

• But correlation is not causation

Motivation and study skills are good for doing well on tests

Growth Mindset 

• Believing abilities are changeable 

Fix Mindset 

• Believing abilities are not changeable 

Summary 

• Intelligence 

  • Most definitions include abstract reasoning, the ability to learn new things and adapt to circumstances

  • There are multiple theories of intelligence such as: 

    • Spearman's g, Sternberg’s triarchic theory, Garner’s multiple intelligences

  • Fluid intelligence is the ability to reason quickly with new material, crystallized intelligence is accumulated stored knowledge

  • Intelligence tests are carefully normed and standardized

  • History of intelligence tests

    • Culturally biased items, discriminatory applications

  • Intelligence correlates with important measures like education and health 

  • Growth mindset 

    • Viewing intelligence as changeable leads to positive outcomes