Cognition and Memory (copy)

Atkinson and Shiffrin's (1968) Model of Memory

• Overview: This model, also known as the multi-store model (MSM), proposes that memory consists of three separate stores: sensory register, short-term memory (STM), and long-term memory (LTM).

• Information Flow: Information flows linearly through these stores. Sensory input is briefly stored in the sensory memory (iconic and echoic), then selected information enters STM through attention, and finally, through rehearsal, it can be encoded into LTM.

Structure, Including the Stores

• Sensory Register: Initial stage for incoming sensory information.

• Short-Term Memory (STM): A temporary store with limited capacity.

• Long-Term Memory (LTM): A more permanent store with potentially unlimited capacity.

Iconic and Echoic Memory

• Iconic Memory: Brief retention of visual information, lasting less than a second.

  • Sperling's (1960) experiments demonstrated iconic memory. Participants could recall letters from a briefly presented grid when cued shortly after stimulus offset.

• Echoic Memory: Brief retention of auditory information, lasting up to 2–4 seconds.

  • Darwin, Turvey, and Crowder’s (1972) study showed that auditory information persisted briefly, improving recall when spatial cues were used.

Short-Term Store (Miller, 1956)

• Limited Capacity: George Miller's (1956) research suggests that STM has a limited capacity of approximately 7 \pm 2 items.

• Research: used digital span tasks to show people can remember about 7 chunks of information at once

• Chunking: Strategy to enhance STM capacity by grouping individual elements into larger, meaningful units.

Strengths and Weaknesses of the Model

• Strengths:

  • Intuitive and systematic framework.

  • Supported by empirical evidence like the serial position effect, where items at the beginning (primacy) and end (recency) of a list are recalled more easily, attributed to LTM and STM, respectively.

• Weaknesses:

  • Oversimplification of memory processes.

  • Fails to explain depth of processing (Craik and Lockhart, 1972), where semantic processing leads to better memory than structural processing, regardless of rehearsal.

  • Case studies of brain-damaged patients like KF (impaired STM but intact LTM) challenge the model's strict linearity.

Working Memory Model of Baddeley & Hitch (1974)

Central Executive

• Function: Supervisory component that coordinates attention and integrates information from other components.

• Role: Task switching and cognitive control.

• Neural Basis: Linked to basal ganglia and prefrontal cortex activation (Dang et al., 2021).

Phonological Loop

• Function: Temporarily stores and manipulates verbal and auditory information.

• Components:

  • Phonological store (inner ear).

  • Articulatory rehearsal process (inner voice).

• Evidence:

  • Word length effect: Participants remember short words better than long ones (Baddeley, Thomson, and Buchanan, 1975).

  • Damage to Broca’s area is linked to phonological loop dysfunction.

Episodic Buffer

• Function: Integrates information across modalities and interfaces with LTM.

• Role: Temporary storage of integrated episodes.

• Neural Basis: Research into the frontal pole (Tsujimoto et al., 2021) suggests that regions like the left frontal pole support high-capacity integration.

Visuospatial Sketchpad

• Function: Processes visual and spatial data.

• Role: Mental rotation and navigation.

• Neural Basis: Activation in the parietal lobes, especially the right hemisphere.

• Impairments: Damage to these areas can result in impairments in spatial working memory.

Strengths and Weaknesses of the Model

• Strengths:

  • Flexibility and ability to account for dual-task performance.

  • Supported by neuropsychological studies involving patients with specific brain lesions.

• Weaknesses:

  • The central executive is ill-defined, often described as a homunculus.

  • Neuroscience suggests a more dynamic and distributed process than the model proposes (McNab & Klingberg, 2008).