Semantic Memory Models and Memory Distortions Study Guide

Collins & Quillian's Hierarchical Network Model

Concepts are represented as nodes in a hierarchy. Properties are stored at the highest applicable level to avoid redundancy (e.g., 'birds have feathers' is stored at 'bird' rather than 'canary'). Example: 'Canary' → 'Bird' → 'Animal'.

Spreading Activation Process

Starts when a concept is activated in memory. Activation moves outward from the node along links. Closer/stronger associations receive more activation. Activation decreases with distance. Explains semantic priming and reaction times in verification tasks.

Smith's Feature Overlap Model

Concepts are defined by lists of features. Defining features: essential for category membership. Characteristic features: typical but not required. Example: 'Robin' - defining: has wings; characteristic: sings.

Feature Comparison Process

Stage I: Quick, global comparison of features. If high or low similarity → fast yes/no decision. Stage II: Slower comparison of defining features only. Used when the similarity is moderate/uncertain.

Empirical Support for the Network Model

Semantic Priming: Faster responses to semantically related word pairs (e.g., 'nurse' → 'doctor'). Hierarchical Effects: Slower response for distant links (e.g., 'A canary is an animal' takes longer than 'A canary is a bird').

Typicality

How representative a concept is of its category. Example: Robin = typical bird; Penguin = atypical bird. Influences categorization speed and judgments.

Semantic Relatedness Effect

Words that are more closely related in meaning are recognized and processed faster than unrelated words.

Typicality in the Network Model

Not explicitly represented in the original model. Later models adjust by: Shorter links or stronger associations for typical items.

Primes & Targets

Prime: Initial stimulus that activates a concept (e.g., 'bread'). Target: Stimulus that follows (e.g., 'butter'). Facilitation: Faster response to target due to prime. Inhibition: Slower response due to unrelated or misleading prime.

SOA (Stimulus Onset Asynchrony)

Time between the onset of the prime and the target. Short SOA → automatic priming. Long SOA → allows for strategic/expectancy-based processing.

Lexical Decision Task

Participants decide whether a string of letters is a real word (e.g., 'chair') or non-word (e.g., 'blorp'). Used to measure reaction times and semantic priming.

Table 7.1 / 7.3 Interpretation

Faster RTs and better accuracy for related word pairs. Supports the spreading activation theory in the network model. Evidence that semantic relationships affect how quickly we access memory.

Neely (1977) Priming Study

Participants expected primes from specific categories (e.g., 'body' → expected 'building'). Priming still occurred even when targets weren't expected. Conclusion: Demonstrates both automatic and strategic forms of priming.

Bartlett's "The War of the Ghosts" Study

Participants recalled a Native American story over time. Recall became shorter and more distorted to fit Western norms. Conclusion: Memory is reconstructive, not reproductive.

Reproduction vs. Reconstruction

Reproduction: Verbatim recall of information. Reconstruction: Memory shaped by prior knowledge and expectations.

Schemas (Schemata)

Mental frameworks for organizing knowledge. Help interpret and recall information. Can lead to memory errors or distortions when expectations override actual details.

Sulin & Dooling (1974) Study

Examined how prior knowledge affects memory. Key Finding: After one week, false recognition rates increased for the famous person condition due to prior knowledge interference.

Scripts & Story Comprehension

Scripts: Organized knowledge structures for typical sequences of events (e.g., 'going to a restaurant' includes ordering, eating, paying). Help with filling in gaps in stories but can cause distortions when recalling details.

False Memory Formation

The phenomenon where individuals recall events that did not occur or remember them differently from the way they happened.

Gist Memory

A type of memory that captures the essence or meaning of an experience rather than the specific details.

Verbatim Memory

A type of memory that involves recalling the exact details of an experience.

Semantic Integration

The process by which individuals combine related information into larger, meaningful units.

Misinformation Effect

The phenomenon where a person's memory of an event is altered by misleading information presented after the event.

Memory Impairment Hypothesis

The theory that original memories can be altered or overwritten by new, misleading information.

Source Misattribution

The error that occurs when individuals confuse the origin of their memories.

Misinformation Acceptance

The tendency for individuals to accept misleading information as truth when they do not clearly remember the original event.

Overconfidence in Memory

The belief that one's false memories are accurate.

Proactive Interference

The phenomenon where older memories interfere with the recall of newer memories.

Retrograde Amnesia

The loss of past memories that occurred before a specific injury.

Anterograde Amnesia

The inability to form new long-term memories following an injury.

Episodic Memory

A type of long-term memory that involves the recollection of specific events, situations, and experiences.

Semantic Memory

A type of long-term memory that involves the storage of facts and general knowledge.

Memory Distortion

The alteration of a memory that can lead to inaccuracies in recall.

Integration Effects

The tendency for individuals to remember more complex sentences that integrate related details.

Intrusions

The recall of semantically related but non-presented words during memory retrieval.

Eyewitness Testimony

A legal term referring to an account given by people of an event they witnessed.

Amnesia

A condition characterized by memory loss.

Case of K.C.

An example of a patient who lost personal episodic memories but retained semantic knowledge.

Loftus & Palmer (1974) Study

A study demonstrating how the wording of questions can influence eyewitness memory.

Bransford & Franks (1971) Study

A study showing how people combine related information into larger meaningful units, leading to false memories.

Roediger & McDermott (1995) Study

A study that tested false memory formation through the recall of related words.

Loftus et al. (1978) Study

A study that illustrated memory distortion through misleading information about a car stopping at a stop sign.

Semantic Memory Dissociation

A condition where semantic memory is intact while episodic memory is impaired.

Case of K.C.

Had no personal episodic memories but retained semantic facts (e.g., geography, word meanings).

Imaging Evidence

Different brain regions are active during episodic (hippocampus) vs. semantic (lateral temporal lobe) recall.

What Happened to H.M.?

Underwent surgical removal of hippocampi to treat epilepsy, developed profound anterograde amnesia.

H.M. and Implicit Memory

Implicit memory (unconscious) was intact; explicit memory (conscious recall) was severely impaired.

Mirror-Drawing Task (H.M.)

Learned the motor skill of tracing images in a mirror, with improved performance over time despite not remembering practicing.

Source of H.M.'s Amnesia

Damage to the hippocampus, essential for forming new episodic memories; semantic & procedural memory systems were relatively unaffected.

The Hippocampus as a "Pathway"

Acts as a gateway or consolidation hub for transferring short-term experiences into long-term episodic memory.

Explicit vs. Implicit Memory

Explicit: Conscious recall (e.g., facts, events). Implicit: Unconscious memory (e.g., skills, priming).

Tasks Revealing Implicit Memory

Examples include word-stem completion, mirror drawing, repetition priming, and fragment completion.

Repetition Priming - Jacoby & Dallas

Definition: Faster or more accurate responses to previously seen items, without conscious awareness of seeing them.

Jacoby & Dallas (1981)

Participants read a list of words (e.g., "window") and later identified these words better in a recognition task.

Procedural Memory as Implicit Memory

A type of implicit memory for motor skills and habits, knowing how to do things without conscious awareness.

Examples of Procedural Memory

Riding a bike, typing on a keyboard, playing an instrument, mirror-drawing task.

Implicit Memory & Conscious Experience

Implicit memory can influence conscious experience, even if we're unaware of the source.

Examples of Implicit Memory Influence

Déjà vu and gut feelings can arise from unconscious memory activation.

What is a Dissociation?

A condition where one type of memory or cognitive function is impaired, while another remains intact.

How Do Amnesic Patients Reveal Memory?

Through implicit tasks, even when explicit memory is impaired.

Examples of Implicit Tasks

Word-stem completion, fragment completion, mirror drawing, and skill learning.

Retrograde Amnesia

Loss of memory for events that occurred before the brain injury.

Retrograde Amnesia Capacities

Can often learn new things (intact anterograde memory) and may retain semantic knowledge and procedural skills.

Retrograde Amnesia Impairments

Difficulty recalling episodic memories from the past.

Brain Area Linked to Retrograde Amnesia

Commonly linked to damage in frontal and temporal lobes.

Example of Retrograde Amnesia

KC had severe retrograde amnesia for personal events but retained semantic memory.

Anterograde Amnesia

Inability to form new long-term explicit memories after the injury.

Anterograde Amnesia Capacities

Implicit memory remains intact and retains earlier life memories (before injury).

Anterograde Amnesia Impairments

Severe deficit in forming new episodic and semantic memories.

Brain Area Linked to Anterograde Amnesia

Typically results from bilateral damage to the hippocampus and surrounding medial temporal lobe.

Example of Anterograde Amnesia

H.M. could not form new episodic memories but retained old semantic knowledge and intact procedural learning.