Memory Chapter 4

Chapter 4: Working Memory

Introduction to Working Memory

• Mental Arithmetic Example: Multiplying 27 × 3 serves as a practical illustration of the active engagement of working memory (WM). This task not only requires recall of multiplication facts but also the manipulation of interim totals, highlighting the dynamic nature of WM in everyday calculations.

• Working Memory (WM): Refers to the cognitive system that temporarily holds and processes information. It is crucial for tasks requiring manipulation of information, such as mental arithmetic, comprehension, and reasoning. WM allows individuals to juggle multiple pieces of information simultaneously to reach conclusions or solve problems.

The Modal Model: Overview

• Proposed by Atkinson and Shiffrin (1968): This seminal model serves as a foundational framework for understanding the architecture of memory systems.

• Components of the Modal Model:

  • Sensory Memory: Represents the initial interaction with sensory stimuli, where information is processed through brief sensory memory stores (iconic for visual information and echoic for auditory information), lasting only a few milliseconds to a couple of seconds.

  • Short-Term Store (STS): Functions as a temporary holding area for information that requires active manipulation, serving as both a storage system and working memory. It is limited in capacity, often referred to as the "magical number seven, plus or minus two" by Miller (1956).

  • Global Workspace: In the context of WM, the STS acts as a global workspace for selecting strategies and facilitating rehearsal processes aimed at transferring information to Long-Term Memory (LTM). This model underscores the sequential flow of information from environment to sensory memory, to STS, and ultimately into LTM.

Model Simulation: Focused on Rote Rehearsal

• Rote Rehearsal of Verbal Items: Emphasizes the method by which items in STS can be repeated verbatim to promote their transfer to LTM.

Limitations of the Modal Model

• Challenges to the Model:

  • Levels of Processing Theory by Craik and Lockhart (1972): This theory posits that deeper levels of processing—semantic rather than structural—significantly enhance memory retention, challenging the assumption that time spent in STS alone guarantees learning.

• Neuropsychological Evidence:

  • Case studies of individuals with impaired STM yet intact reasoning abilities suggest that STM deficits do not directly predict efficiency in long-term learning. For instance, some individuals, such as secretaries or drivers, may demonstrate remarkable capabilities in complex tasks despite significant STM limitations.

Evolution of STM Understanding

• Complex Ideas About STM: The field has rapidly advanced, with traditional models struggling to accommodate new data from experimental methods, leading to a shift in focus toward elucidating LTM functions and the interplay with Levels of Processing.

• Exploration of WM's Role: Researchers like Baddeley and Hitch (1974) have contributed to understanding STM's function in complex cognitive activities, proposing that this system is integral for everyday problem-solving and decision-making.

Research Methods and Findings

• Experimentation Approach:

  • Baddeley & Hitch (1974): Conducted studies aimed at simulating STM deficits within non-patient populations while simultaneously engaging them in cognitive tasks.

  • Digit Span Task: Participants were tasked with rehearsing numeric sequences while verifying grammatical correctness of statements, designed to observe how increased cognitive load affected WM capacity.

• Results Analysis: Despite an increased cognitive load (up to eight digits), participants managed to maintain performance levels in grammatical verification with only a modest increase in verification time (approximately 50% slower). Error rates remained consistent around 5%, indicating effective WM utilization despite expanded demand.

Implications for Working Memory

• Supporting WM Hypothesis: The findings support a nuanced understanding of working memory, where performance remains stable even under increasing load.

• Dual Processing Systems: This suggests that WM composition involves at least two concurrent processing systems: one that operates efficiently for comprehension and another slower system influenced by concurrent tasks such as digit rehearsal.

New Model Proposal

• Working Memory Model: Introduces a more sophisticated, functionally oriented framework which underscores the active role of WM in facilitating coherent thought processes and complex cognitive activities, marking a shift from merely viewing WM as a static storage system to recognizing its dynamic capabilities.