Cognitive Psychology Flashcards
Memory
- Memory is the faculty, by which the mind stores and remembers information (Oxford dictionary).
- Memory involves acquisition (encoding), storage, retaining, retrieval, and forgetting.
- Memory processes are closely related to learning.
- Three major processes:
∙ Encoding.
∙ Storage.
∙ Retrieval.
LTM: Declarative vs. Procedural
- Declarative (explicit):
∙ Knowing “what”. Memory for facts and events. These memories are consciously (explicitly) recalled (E.g. your address or what you wore on a night-out)
∙ Relational processing: Items are bound by association to the experience in which they occurred, related events, and other memories. This can result in creating of false memories when relations are retrieved that did not actually occur in the given instance but are common in the network of relational memories. - Procedural (implicit):
∙ Knowing “how”. Memory of skills, how to do things, the use of objects, or movements of the body. These memories are unconscious (implicit) (E.g. playing a guitar or riding a bike).
∙ Procedural memories are accessed and used without conscious control or attention. Often investigated via priming.
Declarative Memory: Episodic vs. Semantic
- Episodic memory: Memory of past events (e.g. times, places, context).
- Semantic memory: Memory of meanings, concepts, facts, and general knowledge.
The Multi-Store Model
- Sensory store: Modality specific, brief, subject to rapid decay.
- Short-term store: Limited capacity, fragile. Forgetting from STM is often explained by trace decay and/or displacement.
- Long-term store: Unlimited capacity. Forgetting from STM is explained by interference, cue-dependent forgetting, and/or problems with consolidation.
Sensory Stores
- Iconic (visual) storage
∙ Information decays in iconic memory after about 0.5 seconds.
∙ With reduced task demands iconic memory lasts up to 1.6 seconds - Echoic (auditory) storage
∙ Unattended auditory information lasts about 2-4 seconds in echoic storage.
Short-term memory
- Supports brief storage and immediate recall.
- Stores information that is currently activated (i.e. attended).
- Activation decay and switching attention cause information to leave the short-term store.
- Decay can be prevented by rehearsal (re-activation).
STM: Memory Span
- Miller (1956) “Magic Number Seven”
∙ The maximum number of units recalled with minimal error is seven plus or minus two.
∙ Memory span is not limited to a certain number of stimuli, but by the number of chunks. - Chunking
∙ Grouping a series of apparently random items into a smaller number of meaningful segments enhances recall.
Serial Position Effects
- Primacy effect: The tendency to better recall the first few items on a list.
- Recency effect: The tendency to better recall the last few items on a list.
Decay Over Time in STM
- Decay of information in STM depends on whether information is rehearsed.
- Without rehearsal (e.g. masked by counting backwards by threes), people forget items in the list almost completely after 18 seconds.
The Multi-Store Model:
Evidence from Neuropsychology
- Are STM and LTM independent? What do we consider classical direct evidence for the distinct nature of brain systems?
- Double dissociation! Patients with distinct LTM and STM impairments (double dissociation)
- Spiers et al. (2001)
∙ Retrograde amnesia: damage to the medial temporal lobe.
∙ Impaired long-term memory.
∙ Intact short-term memory. - Challice & Warrington (1970)
∙ Anterograde amnesia: damage to the parietal and temporal lobes.
∙ Intact long-term memory.
∙ Impaired short-term memory.
Baddeley’s Working Memory System: Central Executive
- Central executive – responsible for directing attention to relevant information, suppressing irrelevant information, effortful control, and for coordinating cognitive processes in multitasking.
- Phonological loop and VSS are central executive’s “slave systems“ responsible for maintenance of information
- Central executive “supervises” and “coordinates” the slave systems.
Implicit Learning
- Implicit learning is a form of learning that occurs when the learner is unaware of what they learned.
1. in the absence of intention to learn
2. in the absence of awareness of learning
3. the resulting knowledge is difficult to express explicitly - Real-life learning nearly always involves both implicit and explicit mechanisms.
- Implicit learning may be most important during early development.
Methods: Artificial Grammar Learning
- Protocol:
∙ Training phase
∙ Testing phase
∙ Debriefing - Results:
∙ Participants perform above chance at testing
∙ Participants are unable to explicitly describe the learned rules
Evidence for Implict Memory from Brain-Damaged Patients
- Double dissociation between performance on explicit (impaired) and implicit (unimpaired) tasks in amnesiacs
- Patients with damage to striatum show impaired implicit performance
∙ Siegert et al. (2006)
∙ Saint-Cyr, Tyalor, and Lang (1988)
Why do we forget?
- Decay theories. Memories fade as a function of passage of time .
- Interference theories. Memories are “forced out” by preceding and succeeding events.
- Cue-dependent forgetting. Memories fade due to lack of supporting contextual cues.
- Memory repression. Memories are (un)consciously blocked due to the high level of associated stress.
- Motivated forgetting. Conscious memory repression.
Saving Method: Ebbinghaus (1885)
- Experimental protocol:
∙ Learn a list of nonsense letter combinations (CVC trigrams).
∙ Recall them at various intervals.
= Forgetting is fastest shortly after learning and the rate then decreases with time.
Forgetting: Implicit vs Explicit Memory
- Forgetting is slower for implicit than for explicit memory
∙ Tulving, Schacter, & Stark (1982): Memory for a word list was poor after one week (explicit memory) but word-fragment completion (implicit memory) was unaffected.
∙ Mitchell (2006): Participants still had implicit memory for pictures 17 years after the initial experiment!
Cue-Dependent Forgetting
- Cue-dependent forgetting – failure to recall a memory due to missing stimuli or cues that were present at the time of encoding (learning context).
- Tulving (1976) :
∙ Retrieval success is directly related to the degree of overlap between the information presented at retrieval and the information stored in memory, including its context. - Thompson and Tulving (1970) - Recall performance is:
∙ Best when strong cues appear at study and recall
∙ Worst when there is a mismatch of cues at study and recall
Memory Repression
- Freud (1915/1963)
∙ Threatening or traumatic memories are often inaccessible to conscious recall. - Most evidence is based on patients with recovered repressed memories.
- Non-experimental evidence, in which adults recover repressed memories is controversial.
∙ Lawsuits sparked a “memory war” over whether recovered memories are reliable.
✳︎ Lief and Fetkowicz (1995): self-report data suggest that recovered memories recalled inside therapy may be more likely to be false than those recalled outside therapy.
Recovered Memories
- Clancy et al (2000) induced false memories in the lab.
✳︎ People are given lists of semantically related words to remember.
✳︎ Later, they often “remember” semantically related words that were not on the list.
✳︎ Those who reported recovered memories of abuse showed higher levels of false recognitions.
Memory Consolidation
- A process that fixes information in long-term memory
∙ The hippocampus is assumed to play a vital role in consolidation process
∙ Prior to memories being stored, unconsolidated memories are highly vulnerable
✳︎ “New memories are clear but fragile and old ones are faded but robust” (Wixted, 2004)
Standard Model of Consolidation
- Information is consolidated by transferring it from one brain region to another (system consolidation)
1. The hippocampus detects and stores novel information
∙ Takes place over hours
2. The information is gradually transferred from the hippocampus to neocortical areas
∙ Takes place over days
∙ Sleep plays an important role in memory consolidation
How do we know STM and LTM are distinct systems?
- Anterograde amnesia: Problems remembering new information learned after the onset of memory loss
- Retrograde amnesia: Problems remembering events old information – acquired prior to the onset of memory loss
Declarative memory
- Episodic memory: Events, Relations
- Semantic Memory: Objects, Word meanings, Facts, People
Are Episodic and Semantic Stores Independent? Evidence from Amnesia
- Anterograde Amnesia: Patients with anterograde amnesia due to damage to hippocampus often have episodic impairments but little or no semantic impairments (Spiers et al. 2001; Vargha-Khadem et al. 1997).
- Retrograde Amnesia: Retrograde amnesia for episodic memory is also more severe than for semantic memory (Tulving 2002; Yasuda et al. 1997).
Constructive Nature of Episodic Memory
- Episodic memory is (partially) a constructive system. Prone to errors and illusions (remember false memories?).
- Why?
►Too much resources necessary to produce a permanent record
►We usually access the gist rather than details. This tendency increases with age (Brainerd & Mojardin 1998)
►Constructive processes involved in episodic memory might be related to prediction - forming future plans
✳︎Amnesiacs with episodic memory loss also have impaired ability to imagine future events (Hassabis et al., 2007)
Episodic memory: How is it studied?
- Recall
- Recognition
Semantic memory
Semantic memory stores facts, categories, and concept. Like a database, thesaurus, or a dictionary
Hierarchical Network Models
- Semantic memory is organized into a series of hierarchical networks (like a taxonomy)
►Concepts are represented as nodes
►Features are associated with each concept
►Each concept possesses features of higher-level concepts in addition to its own features - Hierarchical Distance Effect: Sentences should take more time to process as the number of levels between the tested concept and specific features increases