Cognition: Week 3 Lecture Notes PDF

PSYC21081 Cognition: &21181 Week 3 1 Last week Episodic Memory Semantic Memory 2  ed Overview represent ~ Semantic Memory Organization of concepts...

PSYC21081 Cognition: &21181 Week 3 1 Last week Episodic Memory Semantic Memory 2  ed Overview represent ~ Semantic Memory Organization of concepts Hierarchical Network model Cognitive models / Spreading activation model J The role of context Situated Simulation Theory Neurocognitive models The hub and spokes model 3 S EM AN TI C ME MORY Organisation of concepts 4 Organization of Concepts Semantic memory as the store of knowledge about the world - contains concepts minte / we to X- Concepts: mental representations and the fundamental e units of thought e.g., concept of bird, animal etc. ↳ where a How are these organized? Collins & Quallian, 1969 Hierarchical Network model  Semantic memory organized into a series of hierarchical networks  Major concepts are represented as nodes  Properties/features are associated with each concept ▷ Cognitive economy: properties are stored higher up to minimize redundancy Support  Sentence verification task “Decide as quickly as possible whether sentences are true or false” 7 Sentence verification task Collins & Quallian, 1969 True A canary can sing A canary can fly RT A canary has skin increases False A canary is a fish Figure based on Collins & Quillian, 1969 ▷ Greater distances are associated with longer RTs ▷ when verifying statements about properties of canaries (top) and ▷ about categories of which the canary is a member (bottom) 8  Sentence verification task RT increases ▷ Unless information is directly linked/stored with a concept in semantic memory, we infer the answer from properties of higher nodes. ▷ Making more inferences slows verification 9  Problems with Hierarchical Model o Familiarity: “A canary has skin” is not a familiar sentence When controlled reduces the hierarchical distance effect o Typicality: Verification is faster for more representative member categories, independent of hierarchical/semantic distance - A PENGUIN is a bird -not a typical example - A CANARY is a bird & example typical. a  Spreading Activation Model Collins & Loftus, (1975) 11  Spreading Activation Model Collins & Loftus, (1975) I closebecaule  Semantic memory is organized by semantic relatedness/distance  Length of links indicates the degree of semantic relatedness words that are not related are further in distance From Collins and Loftus (1975). Copyright © American Psychological Association. Reproduced with permission. 12  Spreading Activation Model Collins & Loftus, (1975)  Semantic memory is organized by semantic relatedness/distance  Length of links indicates the degree of semantic relatedness  Activity at one node causes activation at other nodes via links  Spreading activation decreases as it gets further away from the original point of activation further away : more inactive. - A PENGUIN is a bird (slow activation) - A CANARY is a bird (strong activation) From Collins and Loftus (1975). Copyright © American Psychological Association. Reproduced with permission. 13 Support 1 Semantic Priming tasks When presenting one stimulus that is semantically related makes subsequent processing more efficient (e.g., faster) Prime related : faster , + bird Target eagle Response to target is faster 14 McNamara (1992) Prime + red Target rose RTs faster Prime – Target: more activation spread through one, short link 15  McNamara (1992). strong, fasteretated ↑ Prime Prime + + red Target red Target weak & rose flower further T because unrelated RTs faster RTs slow - Prime – Target: more activation spread Prime – Target: less activation spread through one, short link through lengthier link via extra node ▷ Semantic links and distance determine the strength and the speed of activation spread from one concept to the other -- 16 Support 2 Deese–Roediger–McDermott (DRM) Paradigm Study doctor Y common associate : SICK HOSPITAL DOCTOR PATIENT NURSE Support 2 Deese–Roediger–McDermott (DRM) Paradigm Study SICK HOSPITAL DOCTOR PATIENT NURSE  It is better to present an unstudied concept Support 2 as a studied one ? Deese–Roediger–McDermott (DRM) Paradigm Study Test: Which words did you study? SICK HOSPITAL + DOCTOR SICK PATIENT NURSE HOSPITAL DOCTOR ▷ Activation should spread from all the presented words to the related Studied word (DOCTOR) 19  Spreading Activation Model: Evaluation  The spreading activation model is more flexible than the hierarchical network model.  Pros of flexibility:  The spreading activation model can account for more empirical findings  Cons of flexibility:  The flexibility also reduces the specificity of the model’s predictions  More difficult to test  Spreading Activation Model: Evaluation Limitations:  The notion that each concept is represented by a single node is oversimplified  What about abstract concepts such as ‘justice’?  Does each concept have a fixed mental representation?  Situation/context in which we encounter concepts changes the way we process them  Do different people have similar representations of any given concept?  No consensus on the most appropriate way to measure semantic distance S EM AN TI C ME MORY The role of context 22 Activity The concept of “bicycle” 23  ↓ “Bicycle” bicyclerepresentation “Bicycle”  Principle:  Concepts are processed in different settings  Their processing is influenced by the current context/setting  Concepts incorporate perceptual properties and motor- or action- related properties Situated Examples: Simulation  Activated aspects of “bicycle” concept reflect current goals (Barsalou, 2009): Theory Ride Buy Change tires 26  Support 1 Hauk et al., 2004 – Does access to concepts involve motor system? ▷ Brain areas activated by action words are adjacent to and partly overlap with activations produced by the corresponding movement ▷ Words such as lick, pick, and kick activate parts of the motor cortex C ▷ Great overlap with areas activated when people make the relevant tongue, finger, and foot movements a lot of action motor areas. in 27  Support 2 Miller et al. 2018 – Does the involvement of motor system facilitate access to concepts? Word type Type of response to hand or feet. action words that relate & Response faster Knead, wipe Kick, sprint Response faster between the & the response, when There is consistency meaning the reaction time is much faster. 28  Support 2 Miller et al. 2018 – Does the involvement of motor system facilitate access to concepts? Word type Type of response Response slower Knead, wipe - Kick, sprint Response slower - unrelated slower response. when they are , ▷ Understanding of action verbs requires activation of the motor areas used to carry out the named action 29  Evaluation:  Processing of concepts depends on the situation and the perceptual + motor processes in a given task. Situated  Limitations: Simulation  How variable are concepts across situations? Theory  Concepts = stable core + context-dependent elements  Are these properties secondary – after concept meaning has been accessed? 30 S EM AN TI C ME MORY Concepts in the brain 31  Concepts and the Brain Grandmother Cell Hypothesis Feature-based Approach  Semantic memories are represented in Different kinds of information about a the brain as whole objects given object are stored in separate  Each object/concept has its own node brain regions or neuron  e.g. Visual information is stored in  e.g. There’s a special neuron -visual one part of the brain, while the Cortex representing your grandmother auditory linked with that object is  Types of nodes are grouped together (e.g. all living things) stored in another > - auditoryvex. This view is becoming increasingly  Most evidence suggests that this is not the case popular 32  Actions Sounds Motion  A hybrid model of I semantic memory models : Neurocognitive  Hub: Modality- Hub-and- independent conceptual spokes spoke representations Canterior emperal I model  Spokes: Modality-specific lobe) nush Colour brain areas. Sensory and The “hub” Shape Amodal semantics motor processing G Adopted from Patterson et al. (2007) general ideas are represented here. dispersed brain regions. 33  Support 1 Ishibashi et al., 2018 – tDCS study - Tool function questions (e.g., “scissors are used for cutting”) Tool manipulation questions (e.g.,“pliers Hub-and- are gripped by the handles”) spoke Actions to objects model tDCS applied to IPL (Inferior parietal lobe) Tool manipulation task was enhanced lobe) tDCS applied to ATL(Anteriortemperal Increased performance in both tool Hub semantics function and tool manipulation 34  Support 2 Neuropsychological Evidence Problems with hub. o Semantic dementia Hub-and- spoke model ↳ no anterior temperole General semantic deficits e.g., naming objects, sorting objects in categories etc. - Losing meaning. 35  Support 2 Neuropsychological Evidence Problems with spokes ? o Semantic dementia General semantic deficits e.g., naming objects, sorting objects in categories etc. - memory problems - > Hub-and- o Category-specific deficits spoke action rund. model - S E.g., Greater difficulty identifying/naming living than nonliving objects Problems with naming living things than non-living things - 36  Support 2 Neuropsychological Evidence o Semantic dementia General semantic deficits e.g., naming objects, sorting objects in categories etc. Hub-and- o Category-specific deficits spoke Patients (K.C. and E.W.) with category-specific memory model ▷ Able to correctly name pictures of non- living things: -non-living ▷ e.g., car and table ▷ fruits and vegetables e.g., tomato and pear ▷ Performed poorly when asked to name pictures of animals From Mahon et al., 2009 ↳ living Ring 37  Evaluation  Increasing evidence that concepts are organized in hub (core) + spokes (modality-specific)  Limitations (open issues): Hub-and-  The role of anterior temporal lobe may be more complex spoke  Does familiarity with concepts affect their organization in the model hub?  How many ”spokes”?  How is information integrated between the spokes and the hub? 38 Information within semantic memory is organized in various ways The hierarchical model suggests that concepts are organized in a hierarchical way with nodes and features along a hierarchy Summary: Spreading activation model stresses semantic relatedness and distance between concepts Semantic According to Barsalou concepts incorporate perceptual memory and motor features and their processing is affected by the context in which they are encountered Hub-and-spoke model provides a neurobiological way that concepts are organized incorporating modality- general (hub) and modality-specific (spokes) features  This week’s reading Baddley, Eyesenck, Anderson (2020). Memory. Chapter 7 (pages 207 – 229) 40