201 revisions Lecture 1 Donders and the subtractive method -used a frog leg in his experiment Put electrodes in each side of the leg to measure how fast a response neuron went from one rod to the other If it was instantaneous then there would be no time to receive neuronal transmission. - More neuronal distance =more time So we can calculate the speed of neuronal transmission Donders subtraction technique - Can’t measure the speed of though directly, so we have to measure the time to respond instead. This is a indirect measure Donders developed 3 tasks that he thought would demonstrate that we can measure thinking - A; simple detection- detect then respond - B: Choice response detect, discriminate then respond - C: Go-No/Go detect, discriminate, response selection then respond Simple detection is one button one light – respond always Choice is two buttons two lights Go no go is one button and red button Donders concluded that if we subtract the detection response time (rt) from go no go rt, this would reflect the amount of time to discriminate the stimuli (in the case, red from green) Assumptions behind Donders subtractive method - Cognitive processes (stimulus detection, stimulus identification, response selection, response execution) occur in discrete stages such that the output of one stage forms the input of the legs. - That only one stage/processes may be operating at a time (so that means no parallel processing) - That the addition of a stager in no way changes the other stages (this assumption is often referred to as the assumption of pure insertion) Lecture 2 Additive factors logic - Driving from a to b - There are then two stages to this trip - Therefore you can have things that can effect both stages - We can apply neither one or both effects, but no two effects can be placed in the same stage - So you can have 4 combinations like this The two effects in this case is bad weather of bad road conditions which cause bad road driving conditions. This condition can produce a 1 hour time delay to each stage. Our effects So if you were to have a bad trip and both conditions happened in one trip Therefore the time would add to four hours as both conditions add an extra hour 201 revisions Interaction term is when one effect relies on the other -not statistical interaction – additive effects. This tells you that the two manipulations are influencing different stages of processing StagesThis is similar to donders thinking of tasks that have to be completed in a sequential order Differences between donders and Sternberg - Donders subtractive method is based upon the idea of designing different tasks that differ by a single stage. So choice vs go no go tasks- (i.e. comparing driving A to B with driving A to C) - Whereas, Sternberg suggested we have people do the same tasks. So always a choice task but under various conditions. (i.e. always drive A to B, but different road conditions and routes) Lecture 3- statistics Lecture 4Signal detection theory -reality- what is really out there -perception- which is what we experience It is easy to measure reality, for example, we could measure how bright something is using a light meter Perceptions are not always 100% Sometimes we miss seeing something (or hearing something) Other times, we think we can hear or see something You can either have a hit- this means you are correct Miss- you are incorrect False alarm- you thought you saw something Correct rejection- correct in not seeing something In order to measure the strengths of the perceived signal, we need to calculate something called d-prime (written as d’) Response bias can affect the accuracy of these tests -response accuracy may reflect this -things like the reward can affect the way you answer D prime -the measure of our response bias is not as well established, but we will use one called ‘c’ (criterion) -We can calculate these based upon hit rate and false alarm rate -have to remember that our perception is based on what we see and extract from the stimulus - we do not get the exact same amount if information on each trial because sometimes we see it and sometimes we do not - if we did have the same information every time, we would either always see or always miss the same information 201 revisions (watch second half to understand calculations) Lecture 5 and 6 Cognitive Neuroscience EEG -electrical signals from the pyramidal cells These are found at the surface of the cortex and line up at right angles Measure - Electrodes on the scalp pick up these electrical signals - So EEG is measuring the electrical signals produced by the brain activity - MEG measures magnetic signals produced by the electrical current Record all brain activity- however not all of it is related to what we are interested/ or trying to measure -averaging together a whole lot of presentations of the same stimulus event, we average out the brain activity -all that is left is the event related potential ERP Topographies - Just a way to view the activity of all electrodes at the same time - So we might want to see what all the electrodes were doing 100ms after the inset of the visual stimulus in our left visual field (just left of fixation) Important point - Because we measure the brain activity from a distance (surface of the skull) we cannot be sure exactly where the signal comes from - This is due to the electrical voltage from one area could send its signal to a pint on the skull and produce a voltage value of 3 - Another area could send its signal to the same area, where it sends 4 - Our electrode picks up the sum, and tells us 7 - In that case, the electrode tells us we have a voltage of 7, this came from two areas that individually sent the values 3 and 4 - However, as far as we know, one area could have sent all 7 or 3 areas could have sent 3,3,1 or maybe two sent 6,1 or 8,-1 (can be negative) So you have to be careful to not assume that the exact same brain areas are active just because the topographies are the same Different waves - Sometimes we might want to compare the brain activity between two quite different situations - For example, the sentence “I like tea with milk and sugar” makes sense - However, the sentence “I like te with milk and dog” does not We might expect that the brain processes words that produce a semantic violation differently from semantically expected words N400 To makes sure they knew when someone was reading a given word, they presented the words one at a time 201 revisions Eg The Pizza Was Too Hot To Cry N400 effect Cry does not make sense They would also have ‘correct’ sentences, so ones that made sense (like “the pizza was too hot to eat”) They would make sure that the same words were used both as ‘odd’ and ‘good’ endings - Would then record the ERPs to matching and mismatching words Just like the donders would subtract one response time from another, EEG effects are often shown as ‘difference waves’ In the case, the N400 effect is shown by subtracting the match condition from the mismatch Source estimations - Now we cannot know for sure where EGG signals come from, meaning, we cannot locate the sources of the signals with 100% certainty based on the recordings taken at the remote sensors (the electrode) However, if we build in some other information, like if we do not allow for sources in the ‘white matter’ and we do not allow sources to be placed in the ‘ventricles’ then the number of possible solutions can be reduced, and plausible solutions can be found -LORETA is a program that builds in such constraints Lateralized potentials Trying to compare conditions in this case becomes difficult because the lateralized stimuli will activate different hemispheres, and moving each hand activates different hemispheres, so subtractions will pick this up Two lateralized potentials - The N2pc and the LRP - The N2pc has to do with lateralized stimuli and which one we’re attending - The LRP has to do with which hand you are going to move (respond with) Think encoding and N2pc Think response selection and LRP The N2pc is the dame set of operations, except the electrodes are coded as being contralateral to the side the stimulus was on The N2pc shows us that the voltage at the electrode over the opposite hemisphere of where you were attending (to read the word) was more negative than the corresponding electrode over the same hemisphere as the word 201 revisions For the LRP, it means that the electrode over the hemisphere opposite to the hand you moved is more negative relative to the electrode on the same side The N2pc seems to require you to have located the stimulus that needs more processing (i.e., found the red one and it is the one that you pay attentions to) So the N2pc may be related to stimulus encoding The N2pc is bigger if there is more ‘clutter’ in the display, for example, if you have to decide if the red line is vertical or horizontal in the display, the N2pc would be bigger that in the read the red word task. In the fact, the N2pc can even be bigger than a lateralized flash SO TO CALCULATE LATERALIZED POTENTIALS You need two conditions (i.e. attend left and attend right, move the left hand and move the right hand, move the left hand and move the right hand; stimulus on the left and stimulus on the right ) You subtract contra-ipsi electrodes for each condition (this flips one of the conditions) And average those two sets of differences, and put the values on the right side of your map and invert the sign and put that on the left of your map Oscillations (defines change in the way brain responds) The idea of the ERP is thar when some event happens (when the stimulus comes one, when we find the target, when we decide to move etc) some brain activity happens and the same electrical signal is generated each time This is why averaging g many trials does not reduce the ERP The brain activity cycles through positive and negative values If the brain activity ‘resets’ meaning when the stimulus comes on the activity always starts at 0 and goes positive, then negative, then positive then averaging gives us the ERP (like the visual ERP) Averaging cancels out the effect of not allowing oscillations to go as high or as low Large amplitude to a smaller- desynchronization Higher amplitude= higher power Delta wave= 0-4 Hz Theta wave= 4-7 Hz Alpha wave= 8-12Hz Beta=13-30Hz Gamma=30+ Hz These different frequency bands are thought to be related to various aspects of mental activity. However, there is no set rule as to what the bands mean. What band you might want to examine requires reading previous work and experiments As the rule of thumb though, for synchronization, as the frequency gets higher, the distance between the parts working together is getting smaller SO gamma synchronization is probably small areas of cortex, while theta Synchronization is probably small areas of cortex, is probably between brain structures, etc 201 revisions So, once you’ve decided on what band is important, here’s how we look for changes in these bands First filter the recording so that only the frequencies you are interested in get through Second average the filtered trials together This gives you filtered version of ERP Take the filtered ERP and go back to each individual trial and subtract the ERP from the trace Third, square what is left after subtracted ERP Fourth, average these squared voltages Lecture 7 Attending information Overt orienting- is when you direct your eyes towards the stimulus Covert orienting – is when you attend to some location, but do so without re directing your eyes Our attention might be grabbed by some external event like a flash of light or a loud sudden noise When our attentions are automatically captured by an external event, this is called exogenous Orienting However, we know we can choose to attend to some location If we voluntarily orient our attention, then this is called endogenous orienting Limited capacity Information that we process is said to have a limit capacity Buffers Idea of some information is being held, or is stored, while some other information is being processed Bottleneck Would be a point in where the processing stream where information has to be buffered, it implies too much information is coming in, so the system has to deal with some of it, store the rest, and this creates a traffic jam on our information mental highway Auditory attention tasks Dichotic listening tasks- different stimuli are often presented to each ear Monaural listening tasks- stimuli presented to one ear Items presented are repeated back- this is called shadowing This is too ensuring subject is actually paying attention Focused vs divided tasks In a focused attention task, subjects shadow one ear, meaning they only report back the items presented to the ear like the example or only count target words in that ear 201 revisions A divided attention task would require the subject to repeat back all the items (from both ears) or count target words in either ear Broadbent found – Focused When told to focus their attention on one ear, what was generally found was that they could report this information accurately But generally, were unaware of the content of the items in the non-attended ear Broadbent found- focused They could tell if something was presented to the other ear, but could rarely report any of the items that were presented to that ear Broadbent found- divided When subjects had to report all of the items presented in both ears If the items were presented slowly, they reported them back In pairs Broadbent’s filter model Presented in a very metaphorical way, not intended to suggest we have pipes in our heads through which little balls are rolling However, presenting a model in such a metaphorical manner can make it easier 1. A buffer 2. Limited capacity 3. Bottleneck 4. Attention Broadbents model -this early selection model of attention because he suggests attention operates before stimuli are identified That makes the role of attention as being something that selects information from the huge input of stimulation, and allows that selected information to be further processed Problems with the model Makes some clear statement, which can be (and were) turned into predictions Treismans attenuation theory Suggested that unattended information was not completely blocked rather it was simply attenuated (reduced) In other words, attention allowed some information to pass through at full strength and all other information was made weaker Basically, attention would select the information that gets , ‘ full strength passage’ at the earliest point where a difference could be determined which might be Physical cues-syllabic patterns- specific words – grammar- gist The point we get to ‘specific words’ the ‘meaning has been processed’ Physical cues- syllabic patterns- specific words- grammar – gist Deutsch & deutsch (late selection) -proposed idea that there is no capacity except for our ability to maintain information Everything is fully processed for meaning 201 revisions Triesman and Geffen told subjects to shadow the left ear but tap a key anytime the word dog was presented in either ear If D&D were correct, then the unattended dog should be easilty detected since we don’t have to maintain the words However, it was found that targets were more likely to be missed if they were in the nonattended ear Lecture 8 Attention 2 Whole report- recall all items Partial report- name only a few Attention in the visual domain Implies that 1. All of the items are stored initially 2. The storage in brief 3. People scan the information that is stored in order to report the items (move their attention around the buffer) 4. The storage fades before all items get reported during whole report Attention as a spotlight Introduced by posner , describing our attention as a spotlight. Speed/accuracy tradeoffs -It is absolutely vital to measure both response time and accuracy The reason for this is because lets say you only measured response time if you found that people were generally faster to respond in one situation compared to another, you might conclude that the first situation is somehow easier -Would ideally see that when fast response lower accuracy Slow response higher accuracy -If accuracy is changing, and response times stay the same, we can still make comments about which task is easier (the one with higher accuracy, or lower errors) -Visual attention research often employs what is called a ‘cuing task’ . this style of experiment was introduced by posner -Two attentional systems- (endogenous and exogenous) All a subject in the experiment has to do is decide if a small dot appears either in the left box or the right box (simple detection) before the target (the dot) appears, however, they are shown an arrow, pointing to one box or the other or to both single arrows indicate that the target is 80% likely to appear in that box usually, errors are low, and do not differ across conditions. So, I will just show response time 201 revisions figures. However, one would analyses the response accuracy data and present it in a report or a publication! -Posner thought that we were able to show that our attention could be cued reflexively, which is thought to reflect the exogenous system -cueing our endogenous by the use of cues and decide to move our attention, and because we have to keep our eyes still, this is convert orienting Of endogenous attention There are some other differences between endogenous and exogenous attention, these have to with the time course of the effects A time course study various the amount of time that the cue appears before the target is presented The time between the onset of any two events is called the stimulus onset asynchrony or the SOA -reversal of the cuing effect is called inhibition of return Time coursing experiments can be used to determine how fast attention can move to get to some location Probe trial, this is when there is a string of at least 5 letters that is either of a living or nonliving creature, the participants have to respond if it in living and then have to distinguish if there is a spot over the letter by responding with a button press -then to adjust the size of attention spotlight, change the living or non-living part to if the middle letter is a vowel Object based attention, that attention not only is distributed over space but on objects. Using non-informative peripheral cues This means we are talking about exogenous Lecture 9 Working memory Atkinson & shirffrin 3 stage model Memory is not just 1 system Sensory memory – short term/working memory- long term/reference memory -sensory memory Iconic (visual) Echoic (auditory) Tactile Taste Smell Attentional systems are between stages (exo or endo) For example, between sensory and short term 201 revisions Why 3 memory systems? Each of the stages have different properties If they all had the same properties, then we would just conclude that we have one memory system Sensory memory systems - Appear to me modality specific (one for vision, one for audition) - They appear to have unlimited capacity (from the whole report studies - They have a very short duration - If the information is attended to, it can be maintained for a longer period because it gets shifted into a different memory system Early selection vs late Sensory memory – short term/working memory- long term/reference memory This is early as there is no semantics before attention Sensory memory – short term/working memory- long term/reference memory Late selection because we now have such a link with semantics. Working memory - Has a longer duration but is not able to hold as much information - Working memory has a limited capacity which then creates a bottleneck between sensory memory and working memory and attention is thought to act like a traffic cop that selects which information to let through Rehearsing information allows you to hold onto information in working memory The primacy effect- is thought to reflect the fact that the early items are the ones that get rehearsed the most. And, this rehearsal transfers those items into reference memory (long term memory) The recency effect - is thought to reflect the fact that the last items presented are still in the sensory memory and can still be attended to before they fade To get rid of the recency effect, we can use a delayed recall task. Say count backwards from 10 after the last letter is presented -this additional task ties up attention and now the items in the sensory memory will fade Baddeley & Hitch’s model -proposed that working memory was not simply a passive storage system, but was rather a collection of systems that actively processed the information that was out into working memory - suggested that working memory was broken down into a system that was auditory in nature (phonological loop) one that was more visual in nature (visuo spatial sketchpad(and a system that was under voluntary control (the central executive) that was used to maintain each of the previous two systems (sort of similar to endogenous attention) Central executive (similar to attention) 201 revisions Phonological loop sketchpad visuo spatial Episodic buffer Model of working memory is often examined using dual tasks The idea is that if you have to do two things at the same time if they both use the same part of working memory, then the two tasks will interfere with each other But if each task uses different parts if working memory, then each part can do its job, and the tasks will not interfere with each other Turns out, that finger tapping does not remove the primacy effect, which demonstrates that not just any secondary tasks will cause interference If you present words visually, people will rehearse them auditorily. So although working memory has been broken into an auditory system and a visual one . working memory as a whole is not as modality specific as the sensory memories. We can rehearse auditorily what we see (written words) Lecture 10 Amusia and tonal memory How to calculate a note -sound waves are measured in Hz hertz (cycles per second) -one octave higher is 880Hz. So this doubles the frequency -12 equal steps in 1 octave 12 steps = 12 semitones Semi tones sound equally different, but the change in the physical frequency is not equal Amusia - Harder to remember sequences if similar sounding tones The tines are harder to distinguish for the amusics therefore, they must sound more similar So does this means they are really memory problems or a perceptual problem? Amusics also listen to music much less than the rest of population So less experienced with music So cant become experts (less practice ) chase & simon Due to memory failure? Or social environment Claire lecture 1 Introduction to language What is language? Communication is an important component of language but not the only one Language 201 revisions - System of symbols and rules that enables us to communicate Communicate - Impairing or exchanging of information by speaking , writing or using some other medium Speak - Say something in order to convey information or to express a feeling For main listening components - Listening - Reading - Speaking - Writing input output Functions of language - Communication - Thinking - Expressing emotions - Pretending to be an animal - Expressing identity with a group Kanzi - Started learning symbols from humans at nine months of age, but his step- sister Panbanisha began at birth Is language innate - Professor Noam Chomsky, prominent linguist - Meaning and grammar can be separated - Humans possess a language acquisition device consisting of an innate knowledge Innate or learned - Innateness idea stems from observations of the ease which children typically learn spoken language - Criticized by people who do not believe that innate grammar can be general enough to account for learning if such different languages if such different languages. Genetic evidence for innate factors are important -twin pairs ‘strong genetic’ influences on both structural and pragmatic language impairments in children -FOXP2 gene Link between language and thought -contraversal theory developed by Benjamin lee whorf -Language determines of influences thinking -hypothesis of linguistic relativity Sapir-Whorf hypothesis - Certain thoughts if an individual in one language may not be understood by people who use a different language 201 revisions - The way people think is strongly affected by their native languages Strong- differences in language cause differences in thought Intermediate- language influences cognition and memory Weak- language may cause preferences for certain ways of thinking Evidence suggests that the effects of language on thinking are rather weak Evidence of the Whorfian hypothesis - Bermino have only 5 basic colour terms, whereas English regard the two greens as similar - Presented 3 colored stimuli – choose two that are most similar - Both groups had categorical perception based on their own language. E.g. blue and green most similar for berinmo- speaking and green and green most similar for English speaking Language influences perception What about modern trends Gender neutral language - If the reader pays attention he will notice People first language - The deaf man ‘versus ‘ the man who is deaf Language that reflects tolerance of differences and avoids stereotypes and avoids stereotypes Claire lecture 2 Reading and speech perception Orthography vs phonology Letter sound knowledge -what sound do these letters make ‘a’ ‘oo’ ‘ck’ ‘gh’ ‘ch’ (bat, book, clock, rough, yacht) Phoneme awareness - What sounds are in ‘cat’ - What rhymes with ‘cat’ - What word do you get if you take ‘c’ off and add ‘bl’ to the start of the word Research in psychology - Lexical decision task; deciding whether a string of letters form a word - Naming task; saying a printed word out loud as quickly as possible - Eye movement tracking; measures attention to words, tracking, but not all reading processes - Priming; prom word shortly before target word, prime related in orthography. Meaning or sound - Event related potentials; time taken for processes to occur e.g N400 Phonology - The sound system of a language - There are regional differences, but English generally described as having 45 phonemes 201 revisions Phonetic features - Voicing - Placing - Manner - Coded by the IPA Phonological awareness - The ability to hear and consciously break words into syllables, rhyme, onset and rime, and individual sounds or phonemes - C-AT - C-ATAPULT - C-ATASTROPHE Homophones - Same sound but different spelling. E.g. rose, rows, made, maid - Also called homophonic (same sound) - Heterotrophs (different writing) Claire 3 Reading Phonological priming is when a word is immediately preceded by non-word priming (words are processed faster) Word processing - Interactive activation - Dual route cascaded - Connectionist triangle models Word level Letter level feature level word superiority effect a letter string is presented very briefly followed by pattern mask orthographic neighbors stem-step-stew activation of this can - Facilitate speed up) recognition if they are less common that target or - Inhibit (slow down) recognition if more common than target word Strength - influential example of how connectionist processing system can be applied to visual word recognition it accounts for word superiority effect Pseudoword superiority effect 201 revisions Limitation - no account of the role of meaning - does not consider phonological processing - too much importance on letter order (cannot explain reading words with jumbled letters) - does not account for longer words interactive activation model of word reading work? It accounts for - the word superiority effect - top down lexical knowledge affects word recognition reading phenomena that models need to explain - phonology and meaning can be separated affected in developmental or acquired dyslexia - word superiority effect - orthographic neighbor effect (letter features) - semantic priming (context effect) - rapid context effect - word frequency effects - word consistency context effects words in sentences - reading is affected by context (i.e. top down effects) - measured experimentally using semantic priming task - is decision time in a word reading task affected by meaning of preceding word semantic priming effect - lexical decision task. – is 2nd word a real word or nonword - nurse – doctor - library-doctor - faster decision if previous (priming) word is semantically related - suggests that priming word automatically activates stored words in lexicon that are related to the priming word - OR priming word changes expectation (expect that a related word will follow) Lecture 4 Claire Reading processes Dual route cascade model (DRC) Has been used to study reading aloud and silent reading Proposes two main routes that both start with orthographic analysis (identifying and grouping letters on the page into words) Different processes when we read words vs non-words (using route 1) Types of words used in reading tests -regular Irregular Non-words Lexical and non-lexical routes - Route 1 (non-lexical) 201 revisions - - grapheme- phoneme conversion (convert letters into sounds) Allows accurate reading & pronunciation of regular words and non-words (as long as they obey grapheme- phoneme rules) Routes 2 & 3 (lexical) - Naming visually presented words relies more on this route because its faster - Route 2 = lexicon plus semantic knowledge (knowing word meaning) - Route 3 = lexicon only (meaning not involved. Just know how the word us pronounced) Dyslexia Surface dyslexia - Rely on route 1, can read regular and nonwords via grapheme-phoneme mapping. Phonological dyslexia (more common) - Very poor reading nonwords and cannot read new or unfamiliar words DRC can explain different types of dyslexia but NOT deep dyslexia Deep dyslexia (uncommon) - Problems reading unfamiliar words and inability to read nonwords - Semantic reading errors (e.g. ship read as boat) Criticism of DRC model - Consistent words have letter groupings that are always said the same e.g. face, mace, pace, ace, base, case - Inconsistent words have letter groupings that are said different ways in different words though bough rough - Consistency matters Other criticisms of the DRC model - Does not account for individual differences - Assumes phonological processing of visual words is slow - Ignores semantic processes - English writing system only (look at Claire 4) – triangle model Strengths - Evidence supports notion that orthographic , semantic and phonological systems are used in parallel Greater emphasis on involvement of semantics in reading aloud Includes an explicit learning mechanism Limitations - Focus on simple monosyllabic words (as for other models) - Does not explain all cases of dyslexia (e.g. completely intact performance on phonological tasks but with impaired semantic access) - Nature of semantic processing not fully explained What our eyes do during reading Saccades - Ballistic - Once initiated, their direction cannot be changed - Take 20-30 ms to complete 201 revisions Spillover effect, words is fixated longer during reading when proceeded by a rare word rather than a common one Lecture 5 Claire Speech perception - Processes involved in speech perception and comprehension 1. Decode complex acoustic signal into phonetic segments (extract discrete elements) 2. Identify syllables and words 3. Word recognition 4. Comprehension 5. Integrate into context Energetic and informational masking Energetic masking occurs when frequency content and loudness of competing sounds mask the speech signal (bottom up) Informational masking relates to cognitive load and attentional factors (top-down factors) Segment speech - Certain sequences of sound are never found together within a syllable (so indicates a syllable boundary) Context (top down) effects - Interactionist view - - context influences processing at an early stage - Autonomous view- context has late influence Lecture 6 Claire Context (top down) effects Interactionist view- context influences processing at an early stage Autonomous view- context has late influence Sentence context almost immediate on sort processing, supporting interactionist view Ganong effect on categorical perception - Word context affects categorical perception - Referred to as lexical identification shift TRACE model - Network model based on connectionist principles - Assumes interaction of both bottom and top down processes - Three levels (speech features, phonemes words) Key components - Speech features nodes connected to phoneme nodes connected to word nodes - Nodes influence each other in excitatory or inhibitory manner to produce a pattern of activation (trace) - Connections at the same level inhibit - Bottom up activation from word features proceeds upwards, context effects cause downward activation - The word recognised will depend on activation level possible candidate words For and against the trace model 201 revisions - Explains lexical identification Includes interactive effect Predicts word frequency effects on speech perception Copes with noisy data Against - Exaggerates importance of top-down processing - Model assumes top-down processing will compensate - Problems with Variable timing of speech rates between speakers - Relies heavily on computer stimulations of recognition of one- syllable - Does not consider all factors such as written form effects on word recognition Cohort model - Words similar to what is heard are activated word initial cohort - Words eliminated if do not match further information such as semantic or another context - Processing continues until all other possibilities are eliminated recognition point uniqueness point - Context affects word recognition at a fairly late stage of processing - Supporting evidence from cross-modal priming Facilitation effect - Doe target visuals probes in each of the tree contexts, even at a late stage in word processing. Results consistent with revised cohort model as the facilitating effect of context were most evident in a later stage of word processing Cohort model Strengths - Processing of competitor word is correct - Processing of words is sequential - Uniqueness point is important - Context effects occurs at integration stage Weakness - Context can affect word processing earlier - De-emphasises the role of word meaning - Ignores the facts that prediction of upcoming speech is important Route 1 - Heard word activates meaning and spoken form Route 2 (input lexicon) - Meaning of hears words not activated Route 3 (phonological-deep dysphasia) - Rules about converting heard word into spoken form Claire 7 Comprehending sentences Parsing- the way we separate parts of a sentence, looking at individual information within the sentence Four possibilities for the relationships between syntactic and semantic processing - Syntactic analysis generally precedes (and influences) semantic analysis - Semantic analysis usually occurs prior to syntactic analysis - Syntactic and semantic analysis occurs at the same time 201 revisions - Syntax and semantic are very closely associated and have a hand in glove relationship Grammar -nothing more than just a simple system Ambiguity can either be lexical (single words) or syntactic (sentence/utterance level) Syntactic - Sometimes called structural Where meanings of the component words can be combined in more than one way Two stage models - Stage one only uses only syntactic information to process the sentence - Stage two uses semantic information - Of importance is the temporal aspect of the semantic information- when is it used in parsing Most common model Garden path model Using stage one and then go on to stage two as do not fully understand Minimal attachment – grammatical structure producing the fewest nodes is proffered - New words encountered in sentence are attached to current phrase Late closure Garden path model Strength - Simple and coherent account - Minimal attachment &late closure often influence selection of intial sentences structures Limitations - Word meanings can influence assignment of structure - Prior context and misleading prosody can influence interpretation earlier than assumed - Hard to test the model - Does not account for cross-language differences One stage models - All sources of information (syntactic and semantic) called constraints are used at the same time to construct a syntactic model of the ambiguous sentence Constraint based theory Uses four language characteristics to resolve ambiguities - Grammatical knowledge constraints possible sentence interpretations - Various forms of information associated with a given word interact with each other - A word may be less ambiguous in some ways than others - These permissible interpretations differ according to past experience 201 revisions Verbs - Are important constraints that can influence parsing Verb biases are formed Lecture 8 Claire Language comprehension 2 Concerned with language use and understanding Intended rather than literal meaning Often involves drawing inferences Autism spectrum disorder - People with ASD are often poor at distinguishing between literal and intended meanings - Find social communication very difficult - Weak central coherence Standard pragmatic model - Literal meaning is accessed - Reader/listener decides if it makes sense in the context - If it does not, then we search for a suitable non-literal meaning that makes sense Prediction model - Understands metaphor - Latent semantic analysis component - Construction- integration component Co-cooperativeness principle - Speakers & listeners work together to ensure mutual understanding - When there is a failure of communication between speaker and listen, we rely on common ground to repair it Egocentric heuristic - Effortful for listening to keep working out the common ground between them and the speaker to use egocentric heuristic Lecture 9 Claire Discourse processing - Beyond sentences and single words , looking at a larger text sample - Have to draw inferences to get from one sentence to another Types of inferences - Logical inferences - Dependent of the meaning of the individual word - E.g. widow (only implies female) Bridging inferences - Establishing coherence between current and preceding text Elaborative inferences/towards inferences - Add details to text from general knowledge 201 revisions Theories in what inferences to use - Constructionist approach - Numerous elaborative inferences drawn when we read a text - -constructionist approach - Numerous elaborative inferences drawn when we read a text - -readers constrict a relatively complete mental model of the situation and events referred to in the text - -comprehension requires our active involvement in to supply information Minimalist approach - -Only a few inferences drawn when we read a text - -automatic when reading - -establishes local coherence (chunking words) - -relies on information readily available because it is explicitly stated - -formed in pursuit of our goals as readers. (goals vary for why you are reading) - -elaborative inferences are made to recall rather than during reading Anaphoric resolution - Simplest form of bridging inference - -pronoun or noun has to be identified with a previously mentioned noun or noun phrase Complex inferences - -causal inferences are common form of bridging inference - -assuming something caused something else - Ken drove to London yesterday, the car kept overheating - Assuming he was driving in a old model - Bonding (low level process involving automatic activation of words) - Resolution (ensure the overall interpretation is consistent with contextual information) Evaluation - Readers and listeners form bridging inferences to make sense of text - Use contextual information and our world knowledge to form inferences - Drawn automatically (many times) - Readers goals influences predictive inferences - Superior reading skills draw more inferences - Discourse comprehension - Remember main themes/events and leave out minor detail - Where have schemas about the world, people action, use when recalling or describing what we have read Bartletts theory - Schemas theory- helps us understand a story - Rationalization- comprehension errors to make the story fit expectations 201 revisions - -memory for precise details are forgotten Schematic information is not Schemas Influences comprehension and retrieval of information Schema evaluation Strengths - Schematic knowledge helps with text comprehension and general understanding - Double dissociation in the neuropsychology literature between schema based and lower level knowledge impairments Weakness - Differences in definition of schema - Schema theories are hard to test - When schemas are used is unclear - How they are used is unclear - Exaggerate how error prone we are - Schemas affect both retrieval and comprehension processes Event index model - As we read we are processing multiple layers of information - -five key aspects - Protagonist - Temporality - Causality - Spatiality - Intentionality Lecture 10 Claire Language production Speaking vs writing Four key differences 1. Speakers generally know who is receiving the message 2. Speakers mostly receive moment by moment verbal and non verbal feedback (e.g. boredom) consequently, speakers often adapt what they are saying in response to feedback 3. Speakers generally have less time to plan what they are going to say, whereas typing you have more time 4. Writers usually have access to what they have written even right after they have written it whereas when you say something it is gone, you cannot go back on it and retract Spoken language, generally informal , simple, quick Written language, formal, complex Spoken language -we use strategies to reduce processing demands preformulations 201 revisions Approximately 70% of what we say has been said before. Have a group of words that use In multiple occasion Underspecification -simplified expressions ,meaning not fully expressed Or something and things like that Speech production levels Semantic Syntactic Morphological Phonological Speech planning -occur at level of clause or level at the phrase To resolve differences between speaking rapidly and fluently by flexibility planning Speech errors -spoonerism When the initial letters of two words are switched Freudian slip Believed to reveal the speaker’s true sexual desires Semantic substituting -word is replaced by one with another in similar meaning Where is my tennis bat? Morpheme exchange error -inflections are in place but attached to wrong word Attaching the wrong endings to different words Word exchange errors -two words in sentence are swapped Number agreement error Singular verbs mistakenly used with plural subjects Error detection Comprehension system Through perceptual loop, we detect own errors by listening to ourselves Conflict based account Detection relies on information generated by the speech production system itself rather than a comprehension system Claire 11 201 revisions Theories on speech production Spreading activation (Dell 1986) -when we are preparing to say something, we form a representation at the four levels Semantic Syntactic Morphological Phonological More complex more advanced spreading occurs Nodes within network vary in activation or energy Categorical rules constrain categories of items and combination of categories that are acceptable Insertion rules select the items for inclusion at each level 1. Mixed error effect, incorrect word is semantically & phonemically related to target. Lexical neighborhoods 2. Lexical bias effect- errors ten to be real words rather than nonwords 3. Anticipatory errors- The sound spoken earlier in sentence than expected 4. Anticipation errors- exchange errors Two words with the sentence are swapped 5. errors involve words within short distance Most speech errors are either Anticipatory- sounds/words are spoken ahead of their time Perseverated sounds or words are spoken later than should have been Levelts weaver ++ Word form encoding by activation and verification Three main levels -nodes representing lexical concepts Nodes representing lemmas (representation of words)- when the word is on the tip of the tongue, can’t quite think of it Nodes representing word forms (morphemes) sounds attached to beginning or ending of words Meta-analysis of studies for assessing brain activity -timings in column Conceptual preparation 200ms Lemma retrieval 75ms Phonological code 20ms Production of it 600ms Weaknesses to weaver++ Narrow focuses (single word production) In reality there is more interaction between processing stages than the model assumes Evidence suggests more parallel processing than model allows Aphasia An acquired language deficit in the modalities of listening, speaking, reading and writing Central language disorder 201 revisions Language impairment when all other intellectual motor, sensory functions are intact Cause by brain damage- stroke, brain tumor, traumatic brain injury (not born with it) Broadly divided into fluent and non-fluent on basis of neuropathology and expressive output Occurs at all levels of communication, involves anything to do with numbers Word finding difficulty (anomia) is the underlying characteristic Is tip of the tongue a mild form of aphasia? Brocas aphasia Nonfluent/motor aphasia Slow hating speech (dysfluent) May have presence of agrammatism -reduced phrase length -reduced syntactic complexity 'telegraphic' Omission of function words and grammatical morphemes Wernickes aphasia Fluent/sensory aphasia Fluent speech Normal melodic line Sentences can be long, complex grammar Poor comprehension Not necessarily damage to Wernicke's area Distinction between brocas and Wernicke’s aphasia 1. Implies that brain damage people all have similae patterns of impairment 2. There are several brain areas involved in language processing and theyre interconnected in complex ways 3. People with Brocas aphasia sometimes also have damage to wernickes area and vise versa 4. The findings that people with brocas aphasia have greater difficulty speaking grammatically is language specific 5. Traditional view focuses too much on specific impairments (e.g. word finding) but people with aphasia can also have problems with attention and memory Anomia - An impaired ability to name objects - Errors based on meaning - Errors based on phonology Agrammatism - Produce short sentences containing content words - Lack of function words (the in and) - Lack of inflections Jargon aphasia - Extreme form of fluent aphasia 201 revisions - Severe problems with grammatical processing- both comprehension and production Sever word findings difficulties Numerous neologism Typically unaware of their errors (poor self-monitoring ) so do not attempt to self-correct Seem to speak fairly grammatically Claire lecture 12 Speech as communication Tailoring for the needs of the listener For maxims Relevance- when talk only speak of relevant to situation Quantity-only give as much information as necessary Quality- only give information that is truthful Manner- modify what you are saying so that listeners can understand Co-cooperativeness principles Some maxims are ignored Audience design - Speakers need to take account of specific needs to their listeners (see common ground) Syntactic priming - Speech tends to follow syntactic structure that has been heard recently (e.g. passive construction) Gestures - Used to aid understanding and clarification Prosodic cues - Intonation used to aid meaning Common ground Includes representations of information that is physical, linguistically, culturally co present -speakers generally focus on their own needs -more likely to use when there is interaction Gesture Used by speakers Time and meaning in words being spoken coordinated People who are blind from birth also gesture Why? -type of self-clarification Could be reflexes Self-cueing Discourse markers- words that add no linguistic purpose 201 revisions Writing Involves retrieving and organizing information stored in long term memory Suggest writing is a form of thinking Key processes (not really examinable) -prosper- ideas for expression Translator-converts message to word string Transcriber Evaluator Two strategies used in planning stage Knowledge telling strategy- write down everything about topic Knowledge transforming strategy - occurs with increased writing ability Knowledge crafting stage -when focusing on reader Knowledge effect- tendency to assume that other people share the knowledge we process Hugh lectures System 1 and system 2 - Fast thinking and slow thinking Mentalese - The language of thought Reasoning and deciding - Deductive reasoning with conditionals and quantifiers - Introduction- hypothesis formation and evaluation Decision making and risk - Thinking probalisticallly - Cognitive biases and heuristics Problem solving - Varieties and vagaries - The curious case of insight Creativity - Its measurement and models Different kinds of thinking - Modes or ways of thinking System 1 - Fast High capacity Parallel Nonconsciousness and autonomous 201 revisions - Biased responses - Contextualized - Associative - Does not require working memory System 2 - Slow - Capacity limited - Serial - Conscious and deliberate - Rational - Abstract - Rule- based - Requires working memory System 1 -evolved early Similar to animal cognition Implicit knowledge Basic emotions System 2 - Evolved late Distinctively human Explicit knowledge Complex emotions Cognition Unbounded rationality Formal logic Bayesian logic Expected utility theory Requires system 2 bounded rationality cognitive biases heuristics intuition system 1 activated Reasons why language of thought is not a natural language 1. Preverbal children cannot think 2. Animals cannot think 3. Sensorimotor control is a form of fast thinking 4. Humans understand ambiguity- thoughts are unambiguous 5. Natural language is rarely logically explicit 6. Computers thinking in a natural language Deductive vs indictive reasoning - Deductive reasoning id often reasoning from the general situations to the specific instances. From the top (the theory) down to the predicted results In contrast 201 revisions - Inductive reasoning is reasoning under less-than-certain circumstances, where probabilities are important Deductive inference with conditionals Premise 1 - States the general position that if such and such is true then something follows form its being true Premise 2 - Is the actual situation or fact or observation - The conclusion follows from premises 1 and 2 Premise 1 states if such and such is true then something follows from its being true Premise 2 is the actual situation or fact or observation The conclusion follows from premises 1 and 2 If you = antecedent Then you = consequent Modus ponens (or affirming the antecedent) 1. Of A then B 2. Given that A holds 3. Then can infer that B holds Modus Tollens (denying the consequent) 1. If A then B 2. Given that B does not hold 3. Then can infer that A does not hold Hugh 2 Law induction Theory Hypothesis deduction Observation system 1 is quick to look for a pattern and if I found treat it as nonrandom and predict that the pattern will continue system 2 can be engaged to realise that more than one rule can underlie the given sequence and hence that narrowing down the possibilities involves disconfirming potential rules how might we process of inductive hypothesis formation take place? 1. Holist strategy; the learner takes all of the features of the first positive instance as the initial hypothesis and , as more instances are successfully presented, eliminates any feature in the seat that does not occur with a positive instance 201 revisions 2. Parist strategy; the learner takes a subset of the features of the first positive instance as the initial hypothesis and as more instances are successively presented, adds to or subtracts its features to maintain consistency