Cognition Lecture Notes PDF

**[LECTURE 1: ]** **Ebbinghaus:** - Scientific study of learning and memory. Tested only one participant (himself). - Nonsense syllables (constant-vowel-consonant items, e.g., caz, wux). - Avoided associations with real words. - Explored the rate of learning and forgetting. - He...

**[LECTURE 1: ]** **Ebbinghaus:** - Scientific study of learning and memory. Tested only one participant (himself). - Nonsense syllables (constant-vowel-consonant items, e.g., caz, wux). - Avoided associations with real words. - Explored the rate of learning and forgetting. - He fit 2.5 syllables in one word. **Rate of Learning. The total time hypothesis.** - the amount learned is a function of the time spent learning. **The total time hypothesis:** **Experiment:** List of 16 syllables, learned a new list each day. 24 hours later he recorded how much more time (number of trials) he needed to relearn the list. **Result:** learning linearly related to amount of study. "practice makes perfect". **Expertise and brain plasticity:** - Compared brain volume in taxi drivers relative to healthy controls - The posterior hippocampus of the taxi drivers was constantly larger. - The size of the posterior hippocampus significantly correlated with the time they have spent as taxi drivers. **New learning and brain plasticity:** **Experiment:** medical students scanned at three intervals; before, during, and after intensive exams. **Results:** increases in grey matter volume in the parietal cortex (A) and in the posterior hippocampus (B), remained even three months after studying. **Practice drives structural plasticity:** - These changes are assumed to be part of the proof that optimizes learning, but the structural changes are not perpetual. - Over time, the brain renormalizes the volume in the regions enhanced by practice - Some structural changes (related to learning a task) may be selected and some may be dropped. **Repetition:** - Simple repetition with no attempt to organize the material might not lead to learning. Especially if the information is complex and is not perceived as useful. Memory and attention are very selective -- even after extensive practice/exposure information is not registered if not deemed important. Distributed practice/ spacing effect: - Distribute learning trials sparsely across a period of time. - Faster improvement rates of learning and less forgetting. - **Caveats:** distributed practice takes longer (i.e., less actual time but more days) -- not always practical or convenient. Individuals may feel "less evident". **Melton (1970): spaced learning of word stimuli increases subsequent recall** **Experiment:** - List of words (one at a time), some presented once and some twice. - Those presented twice appeared after variable lags (from 0 to 40 intervening words). - Also varied the duration of the presentation of each word (1.3s, 2.3s, 4.3s). **Results:** - Memory benefits occur despite the total study was the same between 2-word presentations. - Only the spacing differed. - Lag effect = benefit of repeated study increases as the lag between study occasions increases. **Baddeley and Longman (1978): Rate of learning typing skills under 4 training schedules** **Kornell and Bjork (2008): Spacing and participants' views** - Spaced presentation led to much better identification of new paintings by the same artist. - Participants reports the superiority of massed learning despite showing the opposite effect. **The testing effect/generation effect:** **Karpicke and Roediger (2008)** - To showcase the importance of testing they assigned 4 groups to learn Swahili-English word pairs over the course of a week. § Group 1 (ST): Word pairs repeatedly studied and tested. § Group 2 (SNTN ): After successful recall, the word was not studied or tested further. § Group 3 (STN ): After successful recall, the word was not tested (they continued to be studied). § Group 4 (SNT): After successful recall, the word was not studied (they continued to be tested). **Conclusion:** - The presence of tests had a major effect on what was remembered 1 week later. **The Testing Effect** - § The effect shows that having to retrieve the answer, rather than being presented with, leads to greater retention. **Feedback!** - § Errors in recall when training may affect later recall unless corrective feedback is provided - § The erroneous retrieval may be strengthened in memory **Karpicke & Blunt (2011)** **Experiment:** - § 4 groups studied a science text - § Group 1: Studied passage once - § Group 2: Studied passage 4 consecutive times - § Group 3: Studied text + created a concept map (graphical diagrams of concept relationships) - § Group 4: Studied text + test (recall) immediately Tested 1 week later: - § Testing (G4) promoted superior memory for facts but also inferential questions from the text - § Students believed retrieval practice to be the least effective method of study **Expanding Retrieval Method** **Landauer & Bjork (1978)** - Spaced/distributed practice - Testing/retrieval practice **Spacing effect =** spaced presentation enhances memory. Based on this alone, study and test should be separated as much as possible. **Testing effect =** successfully generating items strengthens memory than passive presentation. The sooner an item is tested after initial presentation, the more likely it will be recalled and strengthened. **The effect of motivation:** **Motivation & Learning** Ø Motivation to learn may make learning more efficient in both automatic and strategic ways **Automatic:** Ø External (e.g., reward) or internal (e.g., curiosity) motives before exposure to stimuli improve memory even when time spent studying or strategies used are controlled **Strategic:** Ø People use deeper and more elaborate memorization strategies for high-value items **Curiosity:** How curious you are to learn something may affect your internal motivation to learn. **Gruber et al. (2014): Curiosity during learning affects later memory** **Motivation: Conclusion** - Internal motivation, such as curiosity has a major effect on successful encoding, not just for the item triggering curiosity but for other incidentally presented stimuli - Curiosity creates a powerful state that favours encoding of new information (even incidental) - Similar findings have been found when external incentives - e.g., reward or exploration of novel situations -- are involved - All of these states are associated with changes in a network of brain regions that critically involve the hippocampus LECTURE 2: Episodic memory = memory for specific events located at a specific point in time. - Mental time travel - Backwards to relive earlier episodes. - Forward to anticipate & plan future events. Semantic memory = memory for facts - No mental time travel - E.g. world knowledge; vocabulary; rules; etc. - Short delay: information is recalled in episodes. - Long delay: the same information integrated into semantic memory. **Episodic vs Semantic** Are these different memory systems? Functionally different: - ▪ Different types of information - ▪ Different experiences Are these different memory systems? **Neuropsychological evidence:** - ▪ Spiers, Maguire, and Burgess (2001) → 147 cases of amnesia - ▪ Substantial or even dramatic loss of episodic memory - ▪ Semantic memory effects more variable and generally smaller - ▪ Damage to the hippocampus (and the MTL) affects episodic memory far more than semantic memory - ▪ BUT: Hippocampal amnesia may affect the acquisition of new semantic memories more, than the retrieval of old (remote) semantic memories (Clark & Maguire, 2016) - ▪ Semantic Dementia patients: Severe loss of concept knowledge but intact episodic memory (and intact cognitive abilities) - ▪ Damage anterior frontal and anterior temporal lobes **Conclusion:** - Independent systems - But many long term memories consist of a mixture of episodic and semantic aspects. - They dynamically interact and affect each other. **Meaning and schemas: Bartlett's approach** - ▪ Recall of complex materials (e.g., drawings and folk tales) - ▪ Examined recall errors - ▪ Unlike Ebbinghaus, he stressed participants' effort after meaning - ▪ Give meaning to studied materials as a better way of organizing thought and eventually memory **Schemas:** ▪ Structured representation of knowledge about the world, events, people or actions ▪ Can be used to make sense of new material, to store and later recall them ▪ Are influenced/determined by social and cultural factors **"The War of the Ghosts"** - Native American folk tales - People committed many errors and distortions when they asked to recall these. - In their recall made the story more coherent and omitted details. - These distortions were more consistent with their own semantic knowledge. - Recalled stories were "westernised" - Criticism: vague instructions. **Bransford & Johnson, 1972** - Participants read the passage, in the absence of title, recalled around 2.8 different units (ideas) - Those supplied with the title "Washing clothes" recalled 5.8 ideas - Previous schematic knowledge is beneficial for later recall as it helps comprehension of the passage and organization of its elements **Role of Schemas:** **Sulin and Dooling (1974)** - ▪ Story about dictator -- "Gerald Martin" (unknown) or "Adolf Hitler" - ▪ Test sentence: "He hated the Jews..": Short delay (5 mins): No difference between the groups. Long delay (1 week): Participants who read about Hitler were more likely to incorrectly agree. Schematic knowledge may affect memory especially at longer intervals **Role of meaning:** ascribing meaning to stimuli affects encoding and storage. **Jenkins & Russell study =** Related words within the list tend to be recalled as a cluster/together (Jenkins & Russell, 1952) **Meaning and memory: conclusion** - When participants are given the opportunity to organise information in a meaningful way, memory performance is guided by meaning. **Visual imagery:** **Paivio's Dual-coding hypothesis:** More imageable words (e.g., concrete nouns) are more memorable. **High imageability (church, beggar, arm, apple**) can be encoded in terms of visual appearance, and verbal meaning. **Low imageability (virtue, history, silence, hope)** can be encoded in terms of: verbal meaning. - Multiple encoding routes improve the chance of successful recall! **Levels of processing theory:** **Why does meaning facilitate long-term memory?** Craik & Lockhart (1972): Levels of processing hypothesis Levels of Processing (LOP): ▪ Words studied and participants asked to make 3 judgments: Visual processing (e.g. "Is TABLE in upper case?" Y/N) Phonological (e.g. "Does DOG rhyme with LOG?" Y/N) Semantic (e.g. "Does FIELD fit in the sentence: 'The horse lived in a \_\_\_."Y/N) Test: ▪ Recognise the words (old or new) **Craik & Tulving (1975)** ▪ Deep processing better recognition -- particularly for "YES" responses ▪ Studies with matched RTs across tasks observed the same effect Deeper coding is better! - § Replicated in numerous studies (various encoding tasks) - § Affects both recognition and recall - § Incidental or not memory test LIMITATIONS AND CRITICISM: - § Difficult to define and measure - § Processing speed ? - § Levels of processing (features) are not processed in a serial order but simultaneously - § Deeper is not always more memorable! PRINCIPLE: - Memory retrieval is best when the cues available at testing are similar to those available at encoding. Example: - Study: pictures of objects (a dog, a house etc.) - Test: pictures or words - Memory is better if format is the same at encoding as at testing (e.g., Köhler, et al., 2000). - LOP effect can be explained in terms of TAP: deep encoding more similar to the way memory is tested. **TAP support:** **Morris, Bransford, and Franks (1977)** **Task:** - ▪ Incidental learning: participants were not told that they would be tested later - ▪ Phonological or Semantic judgments about words **Test:** - ▪ Standard recognition test for the encoded words - ▪ Rhyming recognition test for the encoded words -- e.g., was there a word that rhymed with "bar"? **TAP support:** **Morris, Bransford, and Franks (1977)** **Results:** - ▪ Standard recognition test: same as LOP theory - ▪ Rhyming recognition test: Phonological led to better performance **Conclusion:** - ▪ Learning more efficient when tested the same way was learned **Why is deeper coding better?** - Despite criticism deeper processing of information is advantageous - Craik & Tulving (1975): Richer and more elaborate encoding leads to better memory - Elaborative rehearsal enhances delayed long-term learning more than maintenance rehearsal - Maintenance rehearsal: As something was learned - Elaborative rehearsal: Linking it to other material **Hierarchical organization** Bower et al. (1969): Recall is better when words are organised than when presented in scrambled order. **Organization** - ▪ Tulving (1962) memory is benefited by subjective organization: - ▪ Chunking together separate words for recall, even if those words weren't encoded together - ▪ Items are often chunked together if they: - ▪ linked to a common associate e.g. SYRINGE, POINT, HAYSTACK, and KNITTING are all linked to NEEDLE - ▪ Come from the same semantic category (e.g. professions) - ▪ Form a logical hierarchical structure or matrix **Intention to Learn** **Mandler, 1967** Task: ◦ Deck of cards with a word on each ◦ Four groups: - Learn the words - Sort the cards by meaning - Sort the cards by meaning -- will be tested later - Arrange the words in columns **Results:** - ◦ Sorting by meaning with or without knowledge of the test produced similar recall - ◦ Worst recall in the fourth group **Conclusion:** - ◦ Attention to the material and organise them meaningfully is more important - ◦ Intention has minimal effect, while level/type of processing matters more **Summary:** **Factors that aid encoding:** - Create connections: imagery, meaning. - Organisation: recall by groups, present in an organised way. - LOP/TAP: deeper processing, similar encoding (retrieval procedures). - Active creation: generate, test. **LECTURE 3:** **Organization of Concepts** - Semantic memory as the store of knowledge about the world - contains concepts - Concepts: mental representations and the fundamental units of thought e.g., concept of bird, animal etc. - How are these organized? **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" **Sentence verification task** A canary can sing A canary can fly A canary has skin A canary is a fish ▷ 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) ▷ 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 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 - A CANARY is a bird **Spreading Activation Model** ▪ 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 - A PENGUIN is a bird (slow activation) - A CANARY is a bird (strong activation) **Support 1** **Semantic Priming tasks** - When presenting one stimulus that is semantically related makes subsequent processing more efficient (e.g., faster). **McNamara (1992)** ▷ Semantic links and distance determine the strength and the speed of activation spread from one concept to the other. **Support 2** **Deese--Roediger--McDermott (DRM) Paradigm** ▷ Studied Activation should spread from all the presented words to the related word (DOCTOR) **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 **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. **The role of context** **Situated Simulation Theory** **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 Examples: ▪ Activated aspects of "bicycle" concept reflect current goals (Barsalou, 2009) **Support 1** ▷ 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 ▷ Great overlap with areas activated when people make the relevant tongue, finger, and foot movements **Support 2** ▷ Understanding of action verbs requires activation of the motor areas used to carry out the named action **Evaluation** ▪ Processing of concepts depends on the situation and the perceptual + motor processes in a given task. **Limitations:** - ▪ How variable are concepts across situations? - ▪ Concepts = stable core + context-dependent elements - ▪ Are these properties secondary -- after concept meaning has been accessed? **Concepts in the brain:** **Grandmother cell hypothesis:** - Semantic memories are represented in the brain as whole objects. - Each object has its own node or neuron. - E.g. there's a special neuron representing your grandmother. - Types of nodes are grouped together (e.g. all living things). - Most evidence suggests that this is not the case. **Feature-based approach:** - Different kinds of information about a given object are stored in separate brain regions. E.g. visual information is stored in one part of the brain, while the auditory linked with that object is stored in another. - This view is becoming increasingly popular. **Hub-and-spoke model:** - A hybrid model of semantic memory. - Hub: modality -- independent conceptual representations. - Spokes: modality-specific brain areas. Sensory and motor processing. **Support 1** Tool function questions (e.g., "scissors are used for cutting") Tool manipulation questions (e.g.,"pliers are gripped by the handles") tDCS applied to IPL Tool manipulation task was enhanced tDCS applied to ATL Increased performance in both tool function and tool manipulation **Support 2** **Neuropsychological Evidence** o Semantic dementia General semantic deficits e.g., naming objects, sorting objects in categories etc Neuropsychological Evidence o Semantic dementia - General semantic deficits e.g., naming objects, sorting objects in categories etc. o Category-specific deficits E.g., Greater difficulty identifying/naming living than non-living objects **Neuropsychological Evidence** o Semantic dementia - General semantic deficits e.g., naming objects, sorting objects in categories etc. o Category-specific deficits Patients (K.C. and E.W.) with category-specific memory ▷ Able to correctly name pictures of non-living things: ▷ e.g., car and table ▷ fruits and vegetables e.g., tomato and pear ▷ Performed poorly when asked to name pictures of animals ▪ Increasing evidence that concepts are organized in hub (core) + spokes (modality-specific) ▪ Limitations (open issues): - ▪ The role of the anterior temporal lobe may be more complex - ▪ Does familiarity with concepts affect their organization in the hub? - ▪ How many" spokes"? - ▪ How is information integrated between the spokes and the hub? **Summary: Semantic memory** - 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 - The spreading activation model stresses semantic relatedness and distance between concepts - According to Barsalou concepts incorporate perceptual and motor features and their processing is affected by the context in which they are encountered - The hub-and-spoke model provides a neurobiological way that concepts are organized incorporating modality-general (hub) and modality-specific (spokes) features. **LECTURE 4:** **Retrieval Process** **Retrieval:** ▪ A progression from one or more retrieval cues to a target memory trace through associative connections ▪ The aim is to make the target available **Target Memory Trace:** ▪ The particular memory we are searching for **Retrieval Cues:** ▪ Bits of information about the target memory that guide the search **Associations:** ▪ Bonds that link together items in memory ▪ Vary in strength Spreading Activation **Activation Level:** ▪The internal state of a memory, reflecting its level of excitement ▪Determines accessibility of the item ▪Increases when: Something related to the memory is encountered ▪Persists for some time **Spreading Activation:** ▪ The automatic transmission of "energy" from one memory to related items via associations ▪ Proportional to the strength of connections **Pattern completion** - Retrieval: reinstatement (via spreading activation) of features that represent a memory. - Features, provided as cues, will spread activation to other features, completing the missing components. - Pattern completion = the process by which spreading activation from a set of cues leads to the reinstatement of memory. - Pattern completion is regarded as a hippocampal mechanism. **Factors:** **Factors Determining Retrieval Success** - All related to the relationship between cues and target memory 1. Attention to cues - reduced attention to a cue impairs its ability to guide retrieval. - Dividing attention (task 1 -- recall or recognise lists of words presented auditorily, Task 2: ◦ Make judgments about visually presented items, which were either: ◦ Words ◦ Pictures ◦ Numbers) - Memory is context-dependent - Context reinstates original encoding environment and facilitates retrieval - Principle of encoding specificity: we encode information along with its context **Recognition Memory** **Dual-Process theory** **Familiarity:** **Recollection:** **Recognition Memory: Measuring** Remember/Know Procedure (Tulving, 1985) Participants decide Remember the item being presented previously: - §Recollect contextual details - §Measure of recollection **Know it was presented previously:** - § Seems familiar - § Measure of familiarity **LECTURE 5:** **FORGETTING** Incidental Forgetting = occurs without the intention to forget. Motivated forgetting = purposefully diminish access to memory (e.g., unwanted memories). **SUPERIOR AUTOBIOGRAPHICAL MEMORY** - Uncontrollable remembering - Feels as though the person relives the events they remember - Remembering is "automatic", effortless, and not under conscious control - Cannot forget unpleasant memories. - Memories can be distracting. **FORGETTING RATE** **Do we forget at a constant rate over time?** - Forgetting increases as time progresses BUT the rate of forgetting is different. - Ebbinghaus studies on forgetting **Forgetting curve** - Logarithmic relationship - Forgetting rapid initially - Less additional forgetting at longer intervals **Meeter et al., 2005** **Aim:** Forgetting rate of public events **Task:** 14,000 participants completed an online study of recall and recognition for 40 events **Results:** - Similar to Ebbinghaus's forgetting curve! - Recall: steep initial drop followed by slower forgetting rate o Recall for events dropped from 60% to 30% in a year o Recognition for same events was less affected **Bahrick et al 1975** **Aim:** - ▪ To explore forgetting rate of personal events/information **Task:** - ▪ 400 US high-school graduates were tested on recalling and recognising names of classmates after delays of up to 30 years. **Results:** - ▪ Recognition of classmates' faces/names remained intact - ▪ Match up names with faces also unimpaired - ▪ Recall a name when given a person's pictures was extensively impaired - ▪ Rate of forgetting was similar to Ebbinghaus forgetting curve **Bahrick, 1984** **Aim:** - ▪ Explored forgetting of foreign language taught at university **Task:** - ▪ Tested graduates attending annual alumni reunion **Results:** - ▪ Forgetting levels out after a period of 2 years - ▪ Little forgetting after this period **Availability vs Accessibility** Recall is generally worse after delays than recognition → A distinction should be made between: Availability: - ▪ Is the item in memory store? Accessibility: - ▪Is the item accessible for retrieval? Factors that Discourage Forgetting ▪ Better learning at the beginning ▪ Repeated attempts to retrieve -- (testing effect/ generation effect) builds up resistance to forgetting (e.g., Linton, 1975) ▪ E.g., Linton (1975): effect of testing on personal memories Incomplete or inaccurate retrieval may lead to memory distortions! ▪ But not all memories are equally vulnerable to forgetting at all points in their history -- remember the forgetting curve! Factors that Discourage Forgetting Jost's Law: ▪All else equal, older memories are more durable and forgotten less rapidly than newer memories ▪New memories are initially more vulnerable to disruption/distortion until they are consolidated **CONSOLIDATION** **Consolidation:** The process that transforms new memories from a fragile state, in which they can be disrupted, to a more permanent state, in which they are resistant to disruption. **Reconsolidation:** The process by which a consolidated memory restabilises again after being reactivated by reminders. - During the reconsolidation a memory is vulnerable to disruption. **Consolidation & reconsolidation cycle** Present event/encoding consolidation period consolidated memory reconsolidation reconsolidated memory. CAUSES OF INCIDENTAL FORGETTING 1\. Trace decay -- memories weaken due to the passage of time Example: Facts you learned in school fade out of memory 2\. Context shifts -- different cues are available now than the ones available at encoding Example: School is a completely different context than now 3\. Interference -- similar memories hinder retrieval Example: After a biology lecture you forgot what you learned in a chemistry lecture an hour before **TRACE DECAY** ▪ Memories gradually weaken because of the mere passage of time. ▪ Priming and familiarity especially prone to decay ▪ How does decay affect memories? ▪ A memory's activations fade, but the memory itself is intact (stored & available but inaccessible) OR ▪ The memory itself and its elements (i.e., its associations) degrade along with its activity level. **Trace Decay: Biological basis** § Synaptic connections degrade and neurons die as time goes by memories may die or fade in the same way § The opposite biological mechanism may also explain decay (Frankland et al., 2013): - § Neurogenesis (growth of new neurons -- esp. in hippocampus) means that the structure is remodeled and its connections are gradually modified - § Good for new learning -- generation of new associations - § Bad for older memories retained in hippocampus **Trace Decay: Validity** Behaviourally it is difficult to prove trace decay Two important factors cannot be controlled when attributing forgetting to decay: - Rehearsal - Interference from new experiences Memories unavailable or simply inaccessible? **Alternative factors of incidental forgetting** **Correlates of time =** forgetting may not be caused by the passage of time itself but by a correlate of time. **CONTEXTUAL FLUCTUATION** - Similarity between encoding and retrieval context may explain forgetting. - Incidental context differs more between retrieval and encoding over time. - Incidental context is less similar to the remote past than more recent past. **INTERFERENCE** - Similar traces/memories impede retrieval. - It is difficult to discriminate between them. - Similar memories accumulate more over time. - Whenever the cue that can be used to access a memory becomes associated with other memories. **Interference:** - **Competition Assumption:** Memories associated to a shared cue automatically impede retrieval when the cue is presented. - A cue activates all associates (more or less). - The activated associates compete for access to consciousness. - Competitors hinder access to target memory. - Interference occurs due to the negative effect of having competitors. - It increases with the number of competitors a target memory has. - **Retroactive interference =** a memory earlier on. - **Proactive interference =** a memory later on. A memory that happened prior to it. **Retroactive Interference (RI)** - ▪ Introducing a new (second) memory impairs recall of a first memory (especially similar) - ▪ Especially strong interference if the two lists share cues - ▪ More training on the second list results in more first list impairment **Retroactive Interference: Realistic memories** **Baddeley & Hitch, 1977** **Task:** § Rugby players asked to recall the names of teams they played earlier in the season **Control:** § Some players missed certain games, allowing discrimination of forgetting due to decay (time) vs interference from intervening games. **Results:** § Time was not good predictor of forgetting § Forgetting increased with the number of intervening games **Conclusion:** § Forgetting was due to interference rather than decay. § New rugby games interfere with previous ones -- making them less accessible **Proactive Interference (PI)** - ▪ The tendency of older memories to interfere with retrieval of recent experiences and knowledge - ▪ The number of previous learning experiences (e.g., lists) determine the rate of forgetting of new ones - ▪ PI is more severe for recall than recognition **Other causes of forgetting** **Part-set cuing impairment** - ▪The tendency for recall to be impaired by the provision of retrieval cues drawn from the same category of items in memory. - ▪Providing hints may impede memory retrieval! - ▪The impairments is more severe with increasing numbers of cues provided from the same set. How does this work? - ▪ Presenting similar items as cues, strengthens their association to the cue. - ▪ Competition for non-cues increases memory worsens! **Retrieval Induced Forgetting (RIF)** **Anderson et al., 1994** - ▪ Selective/partial retrieval can harm recall of other memories related to the retrieved item - ▪ Compared to baseline items for which no related items had been retrieved - ▪ This has important implications for learning and studying! - ▪ Selective retrieval may contribute to more severe forgetting for information that is not practiced/retrieved **RIF: Implications** **E.g. Crime scene interrogations (Shaw, Bjork, & Handal, 1995)** **Task:** - Study Phase: Watch a slideshow of a crime scene (a party where objects were stolen) - Retrieval Practice Phase: Interrogate subjects about some of the objects in the slideshow **Practice Phase:** - Interrogate subjects about some of the objects in the slideshow **Results:** - Interrogating people about some stolen items impaired memory for related items **Conclusion:** - RIF may have important implications for how witnesses should be questioned **RIF: Implications & Conclusions** o Retrieval (e.g., testing effect/retrieval practice) can be beneficial for strengthening memories BUT o Selective strengthening (i.e., incomplete retrieval): The benefits may diminish as it causes forgetting of other related things **Why do we forget?** **Interference Mechanisms** Associative Blocking: A cue fails to elicit a target trace because it repeatedly elicits a stronger competitor, leading people to abandon efforts to retrieve target **Examples:** - Tip-of-the-Tongue: keep coming up with incorrect response - RI: cues elicit 2nd list blocking 1st - Part--set cuing: Exemplar cues keep intruding - Cue overload: More associates, more likely a wrong answer to intrude **Associative Unlearning:** Associative bond linking a stimulus to a memory trace is punished by weakening it after being retrieved in error - Difficult to demonstrate empirically Example: RIF & RI: Competitors intrude at retrieval practice and are punished **Functional account of forgetting** ▪ Forgetting to control retrieval in the face of competition ▪ May serve a functional purpose and therefore can also be an active process ▪ Facilitates future retrieval attempts of practiced/ strengthened memories by inhibiting competitors ▪ In this sense forgetting is beneficial! ▪ Serves goal-directed behavior and decision-making **Forgetting promotes flexibility and generalisation** - Memory should not be viewed as a means for high-fidelity transmission of information - The goal of memory is to guide intelligent decision-making - Forgetting allows individuals to exhibit flexible behaviour and generalize past events to new experiences - From this perspective, forgetting is not necessarily a failure of memory - It may represent an investment in a more optimal mnemonic strategy