Psychology Chapter: The Serial Position Effect

The Serial Position Effect

• The serial position effect describes how our memory for items in a list is affected by their position.
• Glanzer & Cunitz (1966) found that participants remembered items at the beginning (primacy) and end (recency) of a list better than items in the middle.
• The primacy effect occurs because items at the beginning of the list are rehearsed more, transferring them to long-term memory (LTS).
• The recency effect occurs because items at the end of the list are still in short-term memory (STS) at the time of recall. A mental math task (recall delay) only affects recency, showing its dependence on STS.

Problems with the Serial Position Effect

• It's difficult to distinguish between STS and LTS as they share similar characteristics:
  • Both use acoustic, visual, and semantic coding
  • Forgetting in both occurs due to interference
• The argument for parsimony suggests that memory is a continuum rather than separate systems.
• It is also unclear why we need separate memory systems.

Nondeclarative Memory (Implicit Memory)

• Nondeclarative memory refers to unconscious retention of past experiences.
• It is demonstrated in:
  • Repetition priming effect: prior exposure to a stimulus makes subsequent responses to the same or similar stimuli faster.
  • Word-fragment/stem completion tasks: Completing a word when given its first few letters is faster if you've seen the word before.

Theory of Memory Systems

• Endel Tulving (1972, 1985) proposed different types of memory within the long-term store:
  • Episodic memory: stores personal experiences tied to a specific learning episode.
  • Semantic memory: stores general knowledge, concepts, rules, and abstract ideas. It is not tied to any specific experience.
  • Procedural memory: underlies motor and cognitive skills, such as riding a bike, playing chess, or doing math.

Evidence Supporting Tulving's Theory

• Certain amnesic patients may have damage to one memory system, but other systems remain intact, demonstrating a dissociation effect.
  • Retrograde amnesia: inability to remember events before a traumatic event.
  • Anterograde amnesia: inability to form new memories after a traumatic event.

Case Study: Patient H.M.

• Patient H.M. (Scoville & Milner, 1957; Corkin, 2013) had extensive medial temporal lobe (MTL) resection surgery to treat epilepsy.
• The surgery removed the hippocampus, parahippocampal gyrus, and amygdala, leading to profound amnesia.
• While H.M. exhibited normal IQ, short-term memory, and language abilities, he:
  • Had temporal graded retrograde amnesia for events 11 years before surgery.
  • Could not form new memories after surgery.
  • Could form new procedural memories, despite lacking conscious awareness of the training episodes.

Conceptual Knowledge - Categorization

• A category is a class of objects sharing some relationship.
• A concept is the mental representation of a category.
• Generalization involves identifying shared features within a category.
• Discrimination involves recognizing the differences between categories.

Benefits of Categorization

• Reduces environmental complexity.
• Aids in object identification.
• Minimizes the need for constant learning.
• Enables us to make decisions about appropriate actions.
• Allows us to order and relate different classes of objects and events.

Classical Approach

• Based on lists of defining features, which are essential to an item's meaning.
• Each feature is individually necessary and collectively sufficient to define the category.
• Works well for logical categories like geometric shapes and prime numbers.
• Doesn't account for variability within categories, treating all members as equal.

Natural Categories

• Groups of objects or concepts that occur naturally in the world.
• Have fuzzy borders and overlapping memberships.
• Difficult to define with specific features.

Prototype Approach

• Based on prototypes: idealized, abstract representations that are most typical of a category.
• Concepts are organized hierarchically:
  • Superordinate: broadest categories with few shared attributes (e.g., fruit, animals).
  • Basic: most commonly used, with shared attributes and clear distinction from other basic categories (e.g., apple, dog).
  • Subordinate: narrowest categories, less distinct (e.g., Golden Delicious apple, Poodle).
• Typicality effect: items differ in how well they represent a category.
• Family resemblance: members share at least one attribute with others in the category, contributing to typicality.
• Brain activity: Different brain regions are activated when processing different levels of categories.

Pros and Cons of Prototype Approach

• Accounts for loose groups of objects.
• Allows for variability within categories.
• Reduces information to a single idealized abstraction.
• Does not account for specific information about individual examples.
• Large number of potential features may be challenging to manage.
• Determining the weight of specific features remains unclear.

Feature Comparison Model

• Categorization based on comparing features of an item to stored features of category prototypes.
• More similar features to the category = more likely to be classified as belonging to that category.

Semantic Network Models

• Concepts represented as nodes in a network.
• Nodes are connected by links, representing relationships between concepts.
• Activation of a node spreads to connected nodes, influencing retrieval.

Connectionist Approach

• Concepts represented by patterns of activation across interconnected units.
• Learning involves adjusting connection strengths over time.
• Accounts for human learning and adaptability.

Schema Theory

• Stored knowledge structures that represent general knowledge about objects and situations.
• Different types of schemas:
  • Scripts: knowledge structures for familiar events (e.g., going to a restaurant).
  • Person schemas: knowledge about particular individuals.
  • Role schemas: knowledge about social roles (e.g., teacher, doctor).
• Schemas can influence memory:
  • Filling in gaps in memory with information from a schema.
  • Overstating information consistent with a schema.
  • Remembering information consistent with a schema even when it was not presented.

Benefits of Schemas

• Simplify and organize the world.
• Make sense of new information.
• Predict future events.

Dual Coding Theory

• Developed by Allan Paivio (1986, 2006) as a theory of cognition.
• Two independent, but interacting systems for storing information:
  • Imagery system: stores images (right hemisphere processing).
  • Verbal system: stores linguistic descriptions (left hemisphere processing).
• Processing can occur in one or both systems.
  • Pictures: mainly image-based processing, but may be labelled (verbal processing).
  • Concrete words: verbal processing, potentially also forming an image.
  • Abstract words: only verbal processing occurs.
• Connections between concepts:
  • Associative connections within the same system.
  • Referential connections between the two systems.
• Activating one concept leads to activation of related concepts.

Support for Dual Coding Theory

• Paivio & Csapo (1969) showed that a faster presentation rate (5.3 items/s) limited participants to one code, while a slower rate (2 items/s) allowed for dual coding, leading to better recall.
• Kounios & Holcomb (1994) found that concrete words triggered more brain activity and activated both hemispheres equally, indicating dual coding, while abstract words activated the left hemisphere more, suggesting single coding.

Criticism of Dual Coding Theory

• Common coding theory argues that all memories are stored in the same way and there's no need for two different systems.

Explore the fascinating Serial Position Effect in memory. This quiz reviews key concepts such as primacy and recency, as well as the experiments by Glanzer & Cunitz. Test your understanding of how position influences recall and the intricacies of short-term and long-term memory.