Lecture 10: Memory part 1

[13 février]

10A: Basics

What memory does 

• Routines and habits 

• Sense of self 

• facts we have about self developed from experiences 

• Social functions 

• Solving problems 

Clive Wearing

• Worst case of amnesia ever seen 

• Episodic memory was impaired 

• Other memory forms remained intact 

• semantic memory: knew his wife

• procedural memory: played the piano

• Distincts memory systems supported by different neural circuits 

10B: Stages of memory

The three stages

• Encoding: learning new info, forming new “memory trace” as neural code 

• memory consolidation to storage 

• Storage: retaining encoded memory trace/neural code

• Retrieval: activating a memory trace via a cue for a purpose

• memory is in patterns  

Neurology 

• Memory trace is formed (encoding) as a hippocampal-cortical activity pattern 

• Retrieval triggers pattern completion of the brain pattern

• memory cue causes the completion 

• Memory is transformed into stable cortical pattern in consolidation 

Memory as systems 

• Sensory input

• Sensory memory 

• 1 second 

• info not transferred to STM is lost 

• Short Term Memory

• consolidated with rehearsal

• 30 seconds 

• info not transferred to LTM is lost 

• Long Term Memory

• back and forth with STM

Sensory memory systems 

• Automatic reflections of a sense 

• Gustatory/olfactory memory 

• memory of the chemical compounds of taste/smell

• smell has very close link to memory 

• Echoic memory

• sound byte held for ~3 seconds 

• Haptic memory

• very brief memory of a touch 

• Iconic memory

• millisecond visual memory 

• vision persistence/afterimage

Afterimages 

• Positive afterimage: visual memory that represents the perceived image in same colors

• helpful for seeing things smoothly 

• helps fills in holes in videos (24 f/sec instead of 75 f/sec)

• Negative afterimage: visual memory in inverses colors of the perceived image 

• lasts slightly longer (few seconds) than positive afterimage 

Length of sensory memory 

• Sperling (‘60): participants viewed for 0.5sec a visual display of 3x4 letters, asked to recall them after a tone  

• whole report: reporterd letters from the whole display 

• partial report: reported only one row of letters at a time over trials 

• Partial report conditions remembered + with - delay 

STM

• Attended info moves from sensory memory to STM

• Located in prefrontal cortex 

• Limited time capacity of 20-30 seconds 

• Very limited capacity (7 ~+-2)

Serial position effects 

• Primacy effect: first item remembered +

• rehearsal -> LTM

• Recency effect: last item remembered + 

• effect eliminated is delay duration >30sec

10C: Multi-store and modal memory 

Chunking

• Strategy of grouping items together meaningfully so + info is represented at once 

• “cat dog pig” instead of “tdi ogg acp”

• Increases with knowledge 

• ex: expert chess players recall + pieces on board than new players if in game, no difference if pieces are random 

Working memory 

• Retention/manipulation of info not in our environment in conscious awareness 

• Guides behavior 

• Essential for many cognitive functions 

• Episodic buffer: integrates info from STM and LTM

• “conscious awareness”

Phonological loop

• Phonological store: passive store for verbal info 

• “inner ear”

• Articulatory control loop: active rehearsal of verbal info

• used to finger written material into sounds 

• specialized role in language 

• “inner voice”

Visuospatial sketchpad

• Visual cache: info about visual features 

• Inner scribe: info about spatial location/movement/sequences 

Separating stores

• Differents brain areas active for visual/break STM tasks 

• Patient ELD has problems recalling visual/spatial but not verbal info short-term 

• Patient PV had problems recalling verbal but not visual material short-term

• both examples of double dissociation 

Implicit/explicit in LTM

• Implicit memory: non-declarative, non-conscious 

• Explicit memory: declarative, conscious 

• Retention Interval Time between encoding and recall

Ebbinghaus

• Learned nonsense syllables and tested me,Roy at various interval to see what was retained/forgotten 

• created over 2000 cards of fake syllables 

• Learned sets under strict conditions to remove confounds 

• read without any inflection 

• read at a consistent pace of 2.5/sec

• did nothing else during experiments 

• Forgetting curve is exponential 

• memory loss is largest early on then slows down 

Effects 

• Spacing effect: forgetting is reduced when learning is spread over time 

• repeated info + valuable 

• Testing effect: retrieving memory after a test leads to deeper encoding 

• active rehearsal 

• participants studied text passage, those who studied + had better ST recall, those tested had better LT recall

Levels of processing theory

• Strength of memory (and forgetting potential) depends on processes used in encoding 

• Shallow: focus on sensory info

• ex: memorizing vocabulary words in new language 

• Deep: integrate higher-level knowledge

• things we know with learned info 

• ex: using new words in a sentence 

• Memory stronger with deep processing

• + elaborate memory traces

Mnemonics 

• Use deep processing 

• Organizational strategies to help encode info 

• Often involves linking new info to prior knowledge 

• new info to semantic info

• Chunking strategies 

• ex: acronym to remember lists  

• Imagery and Method of Loci

• use familiar image to link encoded info together 

• imagery helps memory

Forgetting 

• Decay theory: memories are lost over time due to disuse 

• like a muscle, memory not used gets weaker 

• Interference theory: interference responsible for majority of forgetting 

• encoded memories are labile, need to be consolidated into stable LTM

• in pre-consolidation period, memories susceptible to disruption and interfering info

Effects of interference 

• Proactive interference: prior info interfere with encoding a new memory

• ex: can’t learn new phone number bc of old one 

• Retroactive interference: newly learned info overwrites/interfere with a priorly encoded memory 

• ex: can’t remember old password after forming new one 

• Similarity effect: + alike something is to what’s already learned, the + it’ll mingle and interfere with memory 

Lecture 11: Memory part 2

[15 février]

11A: Encoding specificity hypothesis 

Basics

• Memory retrieval better when there’s overlap in encoding context 

• Context can act as a retrieval cue

• Context can be internal state or external environment 

• state dependent-learning: better retrieval when you’re in the same internal state (feelings, intoxication, etc)

• external context: better retrieval when you’re in the same environment (ex: sea diving vs land experiment)

Transfer appropriate processing 

• Memory depends on relationship between learning/testing

• Highlights importance of encoding context/retrieval cues 

11B: Explicit memory 

Episodic vs semantic memory 

• Episodic memory: specific events and episodes, with encoding context 

• ex: dancing with friends at prom 

• Semantic memory: facts and general informations, without context of learning

• ex: prom happens at the end of secondary school 

Episodic memory and hippocampus 

• Children with hippocampal damage had episodic memory impairment, but normal semantic memory 

• ex: can’t copy an image after a delay, but have a normal factual knowledge 

• Means episodic memory depends on hippocampus 

• this dependency decreases with time  

Semantic dementia 

• Relatively spared at episodic memory tasks 

• Very impaired at word naming/picture matching task

• scored worse than people with Alzheimer’s 

Memory and consciousness 

• Anoetic consciousness: implicit memory, no awareness, no personal engagement 

• Noetic consciousness: semantic memory, awareness, no personal engagement 

• Autonoetic consciousness: episodic memory, awareness, personal engagement 

• called “mental time travel”

Reappearance hypothesis 

• Episodic memory trace recalled the same at each retrieval 

• reproduced, not reconstructed 

• Recurrent memories are unchanged from original events in PTSD 

11C: Flashbulb memories 

Basics

• Vivid memories of significant events 

• emotionally arousing/shocking events 

• retrieve specific details about time/place of hearing the event

Flashbulbs over time 

• People tested about 9/11 recall after 1/6/32 weeks 

• DV: details used, recollection vividness, confidence 

• consistent detail and inconsistent details 

• No detail difference between flashbulbs and everyday memories  

• Flashbulbs ratings of confidence and vividness increase over time while accuracy decreased

• Flashbulbs memories can change  

• ex: a flashbulb (OJ Simpson trial) recalled after 32 months had 70% inaccuracy and 40% major distortion 

Flashbulbs vs episodic 

• Flashbulbs aren’t recurrent recording of events 

• Flashbulbs retrieval changes over time, aren’t resistant to distortion, even if memory feels very strong 

• distinction between subjective/objective memory

• must accept theory that memories are reconstructed  

Memory consolidation 

• Experiences are encoded then consolidated into LTM

• Consolidation: STM to LTM

• Recall: LTM to active memory 

• Reconsolidation: active memory to LTM

• when a trace is activated it becomes de-stable 

• cortical connections can be strengthened/modified, altering how memory trace is reconsolidated 

• retrieval changes a memory trace 

11D: Distortions in memory 

Episodic memory construction 

• Constructing memories at retrieval mean it can be distorted 

• May use semantic memory/schemas to infer the way things “must have been” in a recalled memory 

• insert false info into constructed memory, affecting retrieval

• Semantic knowledge affects retrieving detailed memories 

Schemas and distortion

• Schemas organize/categorize info, provided expectations 

• War of Ghosts experiment (Bartlett, 1932): people read an unfamiliar Native folk story that don’t match western folk stories schema

• they recalled a simplified version of story, became + conventional with each retrieval 

• omissions/alterations to match Western schemas 

• Study scene associated to schema-consistent items removed

Distortion effects

• False memories: familiar feeling can lead to incorrect associated, details can be added to memories in retrieval 

• Misattribution effect: retrieving familiar info from wrong source, failure in source monitoring 

• not remembering where/when accurately 

• Misinformation effect: leading questions can cause false memory formation

• how a question is framed can affect how info is remembered

• Rashomon effect: memories are reconstitutions, it’s why people recall the same event differently 

• the elephant in the dark experiment 

Implanting memories

• People recalled childhood experiences recounted by their parents over three experimental sessions

• A false memory was added to the list by the experimenter 

• 20% of people had a false memory of the event by the end of the third session

• Same processes that help us constructed the past help us imagine/plan the future 

• processes of hippocampal episodic memory 

Summary 

• Episodic memories impacted by prior knowledge 

• memory driven by our expectations 

• Episodic memories reconstructed at retrieval 

• memories aren’t reflections of truth, they’re subject to distortion 

• Distortions can be false memories, but it reflects an adaptive characteristic

• Same processes helping us construct the past help us imagine/plan future 

• processes of hippocampal episodic memory system  

Lecture 12: Memory part 3

[20 février]

12A: Long-term memory

Basics

• Explicit memory: semantic (facts) and episodic (events)

• Implicit memory: priming, procedural, classical conditioning 

• priming: neocortex 

• classical conditioning: emotional responses (amygdala) and skeletal musculature (cerebellum)

• procedural memory: skill and habits, basal ganglia  

Procedural memory

• Automatic behavior/actions 

• Pattern of movements encoded in the brain 

• basal ganglia for motor sequence

• prefrontal cortex for organization 

• + immune to forgetting compared to other types 

Habits

• First rely on explicit memory, with training/exposure, start relying on implicit memory 

• motor action sequences 

• Can form addictions or repetitive thoughts/emotions/OCD

• Habit formation: requires the striatum 

• rats trained in T shape maze with tones to signal reward at left or right end

• Breaking habits: need to inhibit prefrontal cortex 

• removing reward at one end, or making one reward non-rewarding didn’t break the habit   

• cue -> habit -> reward -> new behavior -> new reward

Priming 

• Prior exposure facilitates info processing without awareness

• Word-fragment completion test 

• participants shown list of words, asked to complete words fragments 

• likely to use prior words to complete fragments without knowing it 

Implicit emotional responses 

• Conditioned emotional responses

• adaptive fear responses to scary stimuli 

• Amygdala: implicit emotional memory and modulating explicit memory

• emotional enhancement effect  

Semantic memory organization

• Large units linked to properties with pointers 

• ex: “animal” unit linked to “bird” unit, which is linked to “feathers” property 

• general to specific 

• Spreading activation: automatic activation spread from activated concept to other interconnected aspects  

• spreading activation to features

• ex: thinking about a crow will trigger activation in related bid concepts 

• Semantic priming: related ideas triggered at retrieval 

• train of thought may seem nonsensical 

12B: Amnesia and dementia 

Dissociations in LTM 

• Experimental neurosurgery to reduce seizure activity 

• bilateral medial temporal lobe, and hippocampus, removed

• caused selective episodic memory loss 

HM and the hippocampus

• Had the neurosurgery that removed the hippocampus

• Intact STM, could remember a short list of words for 30 seconds  

• Intact procedural memory, could learn new skill based tasks 

• Intact semantic memory, could recall major childhood event

• Profound episodic memory loss, couldn’t learn new info and recalled his past in sparse details 

• couldn’t remember/describe details of past 

• couldn’t encode new events

• couldn’t imagine the future 

Amnesia type 

• Anterograde amnesia: can’t form new episodic memories

• Clive Wearing

• Retrograde amnesia: loss of memory from before the amnesia onset 

• temporally graded, recent memories + affected than old ones 

• Dissociative amnesia: very rare psychiatric disorder, usually a response to psychological/physical trauma, not injury 

• commonly retrograde amnesia for episodic memory and autobiographical knowledge 

• leads to lifestyle shifts link moving, assuming new identity  

Dreams and amnesia 

• Dreams linked to memory 

• theory that dreaming helps process past experiences 

• Patients with focal bilateral hippocampal damage and amnesia woken up during night and asked about dreams 

• damaged reported - dreams, and they were much - detailed 

Dementia 

• Progressive cognitive/functional impairments due to neuronal death 

• 63% of all dementia cases are Alzheimer’s disease 

• Medial Temporal Lobe regions the first impacted by AD

• Earliest symptom is a episodic memory deficit 

• MCI due to AD (first step): hippocampus and MTL, some memory loss 

• Mild: lateral/temporal/parietal lobes, poor object recognition/reading/direction sense 

• Moderate/Alzheimer’s dementia: spread to frontal lobe, poor judgment, impulsivity, short attention 

• Severe: widespread brain atrophy, language/function loss, basic motor skills 

• Semantic memory: starts in left anterior temporal lobe, convergence zone for semantic concept representations 

• deficit recognizing faces/words/uses of objects 

12C: Differences in memory

Healthy aging 

• Volume loss of ~5% per decade after 40

• not all areas affected equally

• Implicit/semantic memory is impact, episodic/working memory is impaired 

• ability to remember associations is important for episodic 

Cognitive aging theories

• Older adults have déifier in general executive cognitive processes from frontal lobe atrophy 

• slower to process info, can’t inhibit irrelevant info 

• ex: have trouble focusing on one picture and ignore others 

Associative deficit hypothesis 

• Older adults have problems encoding/retrieving associations in memory due to hippocampal atrophy 

• familiarity/single item (non-hippocampal) less affected

• recollection (hippocampal) + affected 

• Older adults had + trouble with face-name associative recognition than younger 

• - trouble in simple face or name recognition 

• Memory test in scanner showed YAs and low memory old adults both used right PFC, but high memory old adult used bilateral PFC

• neural compensation  

Taxi drivers and extreme memory

• Memory and space intimately linked 

• taxi drivers memorize 25 000 streets within 10km radius 

• Taxi drivers performed better on spatial memory tests and had r + posterior hippocampus grey matter volume 

• volume of posterior hippocampus related to years of experience as a driver 

Highly Superior Autobiographical Memory

• HSAM can remember every day of their life in detail 

• enhanced autobiographical memory 

• recalling very detailed daily memories 

• Doesn’t involve mnemonic strategies 

• HSAM people don’t remember a word list better 

• HSAM speific to personal memories 

• Consistency in recalling memories related to OCD symptoms 

• Goldilocks principle: memory words well with just the right amount, not too little or too much 

Lecture 13: Concepts and knowledge 

[22 février]

13A: Concept meaning and organization

Terminology

• Concepts: general knowledge and mental representation of a category

• Categories: items grouped to gueule according to concept

• Exemplars: individual items in a category 

• Generalization: deriving a concept from specific experiences 

Concept organization 

• Superordinate, basic and subordinate 

• super: - precise than the basic 

• sub: + precise than the basic 

• Goes from less precise to + precise 

 Concepts in development and disease 

• Child learn basic, than super, than sub concepts 

• Semantic dementia patients can use basic level concepts, impaired as disease progresses 

• later in illness, use super concepts 

Cognitive economy 

• Organization allows efficient access of knowledge

• Use simplest terms still meaningful for the situation 

• ex: using basic/super for children, sub for experts 

13B: Concept learning and representation 

Classic approach  

• Concepts involve forming rules about lists features

• defining features: necessary/sufficient for category membership 

• characteristics features: common, but not essential for category membership 

• Feature comparison between encountered items and list

• refines what a defining feature is for a certain concept 

• Works well for simple concepts, less for complex/variable/ambiguous 

• ex: a fur-less dog, a student, etc 

Similarities 

• Concepts are defined by resemblance to a collection of features 

• not by defined features

• Items are +/- part of a category, but an item can be categorized in + than 1

• lines can be fuzzy 

Prototype theory 

• Categories formed from overlap of exemplars

• extracted from experience 

• Each category has an abstracted prototypes that’s pre stored in memory 

• represents most common features with other members

• Exemplars included in category network around prototype 

• similar items stored closer together to the prototype than dissimilar items 

• People learned to classified variants of a prototype in dot patterns, classified studied/new/prototype patterns

• didn’t see the prototype

• worse at classifying new patterns than old 

• equally able to classify prototype and old patterns 

• Prototype is an abstracted exemplar 

• other members remember prototype to certain degrees 

• + obscure members are further away in network

• Typicality effect: preference for processing items close to the prototype

The role of context 

• Prototype theory: concepts are context independent 

• don’t account for situation determining concept representation 

• Context affects typicality effect 

• faster/easier to recognize a concept if it’s in line with its context/surroundings

Exemplar theory 

• No single abstract prototype for a concept 

• every instance of a category is stored, not just prototype

• Two steps to see if new item is part of a category 

• retrieve some/all exemplars of category members 

• compute similarity to new item at time of concept determination 

• Explains how context influence concept representation 

• experience/situational context used to form concepts at retrieval 

Knowledge based theories 

• Explanation view of concept categorization 

• instead of similarity-based

• Implicit intuitive knowledge used to assess new items 

• Essentialism: certain categories have an underlying reality/true nature that can’t be observed 

13C: Embodied cognition and the brain 

Embodied view of concepts 

• Concepts assessed as function of environment/current goals 

• Processed in different brain networks 

• shift depending on what’s required to be accessed from a concept 

• Can bring together dissimilar members into a single temporary category to meet a goal 

Embodiment and the brain 

• Knowledge stored as sensorimotor neural representation

• accessed representation as function of what info is required 

Perceptual symbols system 

• Perception/conceptual knowledge as perceptual symbols 

• Activating a concept engage certain sensory-perceptions to engage mental stimulation as function of task’s goals 

• highlights importance of perception but also goals in storing/accessing knowledge 

• Property verification task: people faster to respond if a previous trial asked feature from same sense/percept

• concepts represented via senses/perceptions 

Brain representation 

• People passively read action words in MRI scanner 

• Specific brain regions that process movements associated with the words were active 

• Concepts rooted in motor/sensory neural activity  

Neuropsychological case studies 

• Brain injury cases of people with category specific deficits 

• Some have selective impairment in naming living things, some in naming non-living things 

• ex: some can’t name animals, some can’t name tools 

Sensory functional theories 

• Concepts represented by defining feature 

• Living things defined by visual features 

• visual processing regions 

• Inanimate objects defined by functional features 

• motor cortical regions

Lecture 14: Language 

[27 février]

14A: Basics

Definition 

• Shared symbolic system for purposeful communication 

• symbolic: units to reference something else 

• shared: common among a group 

• purposeful: to communicate/translate thoughts 

Flexibility 

• Language acts as a high level control system for the mind, allowing to sculpt mental representation of other and own 

• also sculpted by environment 

• Morphology/complexity decreases with languages spoken 

• Lexical tones partly determined by climate 

• tonal languages spoken + in warmer climates 

14B: Language in the brain 

Aphasia 

• Impaired language function, usually from brain injury 

• Broca’s (non fluent) aphasia: speech halted/difficult to produce, writing usually affected similarly 

• ranges from deficits in producing certain words to problems generating all forms of language 

• deficit depends on amount of damage to Broca’s area 

• expressive aphasia: intact language comprehension, impaired speech production/articulation 

• Patient Tan: large lesion in Broca’s area, could only say “tan”, tried to communicate with tone/inflection/gesture 

• Wernicke’s (fluent) aphasia: written/spoken comprehension affected, language content not meaningful/comprehensible  

• posterior superior temporal lobe damage, mostly left 

• verbal paraphasia: substituting a word with something semantically related 

• phonemic/literal paraphasia: swapping/adding speech sound

• neologism: using made-up words 

• Conduction aphasia: impaired repetition, speech production/comprehension intact

• load dependent 

• damage to neural pathway between Broca’s and Wernicke’s

Lateralization 

• Language often considered left lateralized

• Not fully understood or linked to handedness 

• new data indicate up to 70% of left handed people still have left hemisphere language dominance   

• Broader aspects of language supported by right hemisphere 

• prosody, pitch, mood, attitude, gestures, etc 

• Right side seems important for higher-order non literal language use 

• right hemisphere lesion disrupt ability to interpret/express speech prosody   

14C: Acquisition and comprehension 

Nuturist/behaviorist view  

• Language acquisition is skill/associative learning 

• explicit training of language 

• Trial/error reinforcement and modeling other people’s language 

Chomksy/naturist view 

• Language is not stimulus dependent or determined by reinforcement 

• Language is complex, acquired rapidly 

• Allows us to understand/speak what we haven’t heard before 

• Innateness hypothesis: grammar/syntactic structure separate from semantic meaning/cognition 

• Language Acquisition Device: entity supporting language 

• Universal Grammar: part of LAD that includes rules for all languages 

• children only need to learn language specific aspects to our on top of UG

• Children exposed to different learning situations converge onto the same grammar 

• uniformity of (healthy) language development with age

Stimulus argument poverty 

• Child’s linguistic environment not sufficient to enough to allow the child to learn a language via reinforcement/rules/imitation 

• child doesn’t have enough language samples to acquire all language, not enough opportunities to learn from mistakes

• must be something innate about language 

• Adult reformulation of child’s speech target the structure, not the meaning 

• Children extract regulations from experience to form rules 

• evidence that rules aren’t innate 

Psycholinguistics 

• Buildings blocks of language

• Phonemes: smallest linguistic unit (d, o, g)

• english has a few dozen for morphemes

• Morphemes/words: smallest meaningful units of language

• Syntax: rules governing how words are arranged in sentence 

• Semantics: the meaning 

Basics of comprehension  

• Understanding semantic from language 

• Resolving types of linguistic ambiguity using context/top-down processing 

• phonological: within a sound 

• lexical: within a word 

• syntactic/parsing: within a sentence 

Ambiguity  

• Phonological ambiguity: determining phonemes depends on audio signal, which is often noisy 

• can use context/internal knowledge of speech sounds to hear 

• ex: noisy cafe over your conversation with  a friend 

• Lexical ambiguity: single word can refer to more than one different concept 

• >80% of English words have more than one dictionary entry 

• basis of puns 

• homophones: words that sound the same with different meaning, correct one resolved the sentence context

Cross modal priming task 

• Word “bug” can mean two things 

• One group without context and one biasing context to “insect” meaning 

• Lexical decision shortly (short SOA) after hearing the word bug: both meaning active, bug primes both 

• Lexical decision with delay (long SOA) from hearing the word bug: into context biased meaning active 

• Both meanings initially retired, contextually inappropriate one quickly discarded

Parsing 

• Sentence parsing: diving a sentence into words and identifying them as nouns/articles/verbs/etc

• Ambiguity can come bc we hear sentence incrementally or there’s often + than one way to parse a sentence

• Garden path sentence: sentences with multiple syntax structures 

• interpreting a word one way leads to faulty interpretation 

• Syntax first theory: we use grammar rules to interpret a sentence as we hear/read it 

• local or specific   

• we parse with only grammar principles, in one direction, may get to the end and wrong meaning, must go back 

• Constraint based model: we use non grammatical info to help interest sentences and resolved any ambiguity 

• global or holistic 

• use + than grammar to parse sentence 

• can use semantic/thematic context, expectation, frequency 

14D: Language and thought 

Linguistic relativity 

• Language/thoughts are interconnected 

• Sapir whorf hypothesis: Language changes how we think/perceive

• people who speak different languages think differently 

• ex: Inuits have + words for snow 

• Linguistic universalists: language/thoughts are independent 

Findings 

• Russian, but not English, discriminate between lighter and darker shades of blue

• Russian speaker faster to discriminate blues into divergent categories, English speaker showed not effect

• language affects perception 

• English have more words for color than Indonesian Dani

• suggest accessing color category without language labels  doesn’t change across language 

• both groups match/categorize learned color patches the same 

Dyslexia 

• Surface dyslexia: reads letter by letter, sounds out words 

• difficulty matching words to mental dictionary 

• impaired at producing irregular words (25% of English)

• Phonological dyslexia: reads by comparing whole words to mental dictionary/lexicon 

• difficulty reading letter by letter and sounding out words 

• impaired at reading non words and new words 

Lecture 15: Bilingualism  

[29 février]

15A: History

Traditional story in psycholinguistics

• Bilinguals considered a special group of language users 

• like those with brain damage or language disorders 

• Thought learning two languages would be confusing 

• Bilinguals should be functional monolingual in two languages 

• late bilinguals: learnt second language later than childhood 

• Even successful late L2 learners spell with accent and fail to get subtle aspects of L2 grammar 

New attitude

• Publications about bilingualism jumped around 2001

• Greater plasticity than previously understood 

• Language learning occurs at all ages

• Languages processes are dynamic 

• Bilingualism provides lens to understand neurocognitive processes 

• alters structure/function of mind 

• Bilinguals not two monolingual in one 

15B: Discoveries

Language coactivation  

• Bilingualism is joint activation of two language systems 

• cognates: words same in two language, facilitating 

• interlingual homographs: same word with different meaning, interference 

• Facilitates/interference effects stronger in L2

• and in language from different writing system 

• also present in bimodal bilinguals 

• Bilinguals show effect of parable activation in reading 

• Initial stage of comprehension: first fixation duration (length of 1st time eye fixates on target)

• Later stages of comprehension: length of all eye fixations

• longer fixation durations -> + comprehension difficulty

Impact of L2 on L1

• Bice & Kroll examined cognate effects in monolinguals and L2 Spanish learners with English lexical decision task

• Cognates has no behavioral effect 

• Event-Related Potentials: brain voltage fluctuations time-locked to an event 

• Cognates has no ERP effect on monolinguals 

• Cognates in early L2 learners reduces N400 ERP

• so native language is affected by L2

Cognitive control  

• The inhibitory control model: supervisory attentional system affects inhibitory system but not the goal 

• inhibition: triggered to presence of competition, proportional to coactivation level and prevent intrusion from not used L

• N400 ERP shows no effect between L1 and L2

• however, behavioral reaction time is affected 

• N200 ERP associated to early stage of speech planning to operation of inhibitory processes 

• can be observed as negative shift over front central sites 

• peak between 250/350 ms after stimulus onset  

• Strong cognitive demands needed for language control and brain/cognition are plastic and affected by experience 

• underlies that multi/monolinguals could use their cognitive control processes differently beyond language processing 

• Lifelong management of two languages -> language control enhancement -> enhancement in domain general control -> brain changes  

• Flanker task conflict effect very reduced in bilinguals 

• Bilinguals have greater bilateral frontal gray matter volume compared to monolinguals 

Individual differences  

• Bi/multilingual advantage found in studies 

• other studies question the differences 

• Bi/multi advantages modulate but tasks used to assess executive functions 

• Adaptive inhibition hypothesis: interactional context -> language experience -> language/cognitive processing 

• Dual language contexts may be particularly demanding 

• both language control and general cognitive processes 

• Multilingual langages experiences a continuum 

• Language diversity across social context crucial to regulate language representation/control/accessibility 

• over basic measures like L2 age of acquisition and self reported ability 

Summary  

• Bilinguals are not two monolingual in one, both languages are active and competing 

• two languages not separate

• Bilingual language sustek permeable in both directions 

• L1 changes in response to L2 learning 

• bilingualism affects both languages

• Effects on cognitive control, brain/cognition are plastic 

• Not all bilinguals are the same

• language experiences are multifaceted

• bilinguals differ by context demands and experience 

Lecture 15: Choice 

[12 mars]

15A: Heuristics and biases 

Basics 

• Heuristics: mental shortcuts allowing to skip careful deliberation to draw interference 

• Slow system: serial logical analysis of info

• effortful, non automatic 

• Fast system: heuristics based reasoning 

• easy, automatic 

Availability heuristic  

• Estimate event probability based on ease at which it can be brought to mind  

• Liechtenstein (78) asked which was more deadly between tornadoes and asthma 

• falsely rated tornadoes as deadlier, bc deaths by tornado is easier to come to mind 

• Affect heuristic: tendency to overestimate risk of event that creates large emotional response 

• Sunstein (02): people rated sharks as deadliest animal, especially after being exposed to shark attack media 

Representativeness heuristic  

• Tendency to make inference on basis that small samples resemble the larger population they were drawn on 

• Related to availability heuristic 

• relies on pre existing knowledge structures 

• People base their judgment of group membership based on similarity  

• results in biases 

• Base rate neglect: failing to use info about prior probability of an event to judge event likelihood 

• Conjunction fallacy: false belief that conjunction of two conditions is + likely than either single condition 

• likelihood of event is always higher than likelihood of that even and something else 

Anchoring and adjustment 

• Anchoring: tendency for people to overweight initial info when making decision 

• Kahneman and Tversky (74): people saw roulette landing on big or small number, than asked to make an estimate 

• bigger number on roulette -> bigger estimate 

• Important to design self report scales  

Regression to the mean  

• When a process is rather random, extreme values will be closer to the mean (- extreme) when measured again 

• Can’t always attribute changes in performance to manipulation 

Bounded rationality  

• Bounded rational: theory that humans are rational relative to environmental/individual constraints 

• people are satisficers, we look for good enough  

• « making do » with our humans limitations 

• heuristics provide incorrect answers and lead to biases but they also work 

Ecological rationality  

• Sees heuristic as optimal approach to solve problems

• Given right environment, heuristic can be better than optimization than other complex strategies 

Summary 

• Heuristics/biases arise from limitations we face

• can sometimes produce correct responses (ecological rationality)

• Applying heuristics often lead to biases 

15B: Decision-making processes 

Types of decision making  

• Perceptual: objective criterion for making choice 

• Value based: subjective criterion for making choice  

• depends on motivational state and goal 

• Decisions under risk: when outcomes are uncertain 

• ambiguity: when you have incomplete info out the consequences

Risky decision making  

• Needs to decide even when outcomes are uncertain 

• Both extremes in risk taking can be very harmful 

• stagnancy vs impulsivity   

• Risk premium: difference between expected gains of a risky option and a certain option 

• Risk averse: decision maker has positive risk premium

• most people are risk averse  

• Risk neutral: decision maker has zero risk premium 

• no difference in options 

• Risk seeking: decision maker has negative risk premium 

• don’t need chance of winning + to take a risk 

• Classical economy theory: rational thing to do is choose option maximizing expected value 

• account for individual risk preferences 

• People are inconsistent in preference taken as bias 

• we don’t follow expected value 

The framing effect 

• Display of inconsistent risk preferences depending on problem framing (loss vs gain)

• people are risk averse when options are described as gains 

• people are risk seeking when options are described as losses

• Gachter (09): PhD students could either get a early discount, a late registration fee, or both to cancel each other out 

• 93% of students signed up early when told they would pay a penalty fee 

• only 67% signed up early when told they’d get a discount 

Endowment effect 

• Tendency to ascribe higher value to owned objects compared to identical unowned objects 

• case in which decision framing matters 

• people are averse to give thing up once there’s ownership 

Prospect theory 

• Psychological theory explaining how people make decisions under uncertainty 

• two major features: shape of utility function and shape of probability weighting function 

• Utility: subjective value assigned to an object 

• context dependent 

• assigned to monetary amount as function of current state, not in absolute value 

• losses loom + than gains 

• Probability weighting: how people understand likelihoods

• tend to overestimate rare events and underestimate mundane events 

• links to availability heuristic 

• Fourfold pattern: two features together compared to risk 

• loss-high prob and gain-low prob: risk seeking 

• loss-low prob and gain-high prob: risk averse 

Dual process theory 

• Broad scientific theory that humans possess two decision making systems 

• fast/automatic system vs slow/effortful 

• People gave higher death frequency estimate when in a negative mode 

• Prediction Error: difference between what you predicted will happen and what actually happened

• positive PE: unexpected good outcome, increases positive affect

• negative PE: unexpected bad outcome, increases negative affect

• Mood changes predict risky decision making 

• when people are happy, they’re + likely to gamble