Human memory test #1

Foundations of Human Memory Research and System Differentiation

• Alan Baddeley was the first researcher to investigate human memory experimentally.

• Criteria and types of evidence used to divide memory into distinct systems:

  • Three stages of memory processing:

  • Encoding

  • Storage

  • Retrieval

  • Three primary memory stores:

  • Sensory Memory

  • Short-Term Memory ($\text{STM}$) / Working Memory

  • Long-Term Memory ($\text{LTM}$)

  • Differentiating operating rules and principles:

  • Duration: The length of time information persists in a store.

  • Capacity: The quantitative amount of information a store can maintain.

  • Format: The mental code used to represent information (e.g., visual, acoustic, phonological, semantic).

  • Neural bases and neuropsychological dissociations:

  • Brain-damaged patients exhibiting perfectly normal $\text{STM}$ alongside dramatically impaired $\text{LTM}$.

  • Complementary brain-damaged patients displaying severely impaired $\text{STM}$ alongside completely intact $\text{LTM}$.

  • Evolutionary and species differences across non-human and human organisms.

  • Developmental changes and differences across the human lifespan.

Sensory Memory: Iconic and Echoic Memory

• Nature and function of sensory memory:

  • Serves as a brief, complete, and accurate record of raw sensory input.

  • Retains visual and auditory input briefly to enable visual and auditory perception.

• Subtypes and time tables of sensory memory:

  • Visual Sensory Memory (Iconic Memory):

  • Duration lasts less than half a second, specifically $400\,\text{ms}$.

  • Auditory Sensory Memory (Echoic Memory):

  • Duration lasts up to $3\,\text{s}$.

• Sperling's Paradigm and Experimental Findings:

  • Visual stimulus: A random grid consisting of $12$ letters is presented briefly to participants.

  • Full Report Condition:

  • Participants are asked to report all letters from the visual grid.

  • Outcome: Participants consistently recall about $4$ out of $12$ letters ($4/12$).

  • Partial Report Condition:

  • An auditory tone (beep cue) sounds immediately after the letter grid disappears.

  • Pitch mapping for reporting:

    • High pitch tone: Report the top row only.

    • Medium pitch tone: Report the middle row only.

    • Low pitch tone: Report the bottom row only.

  • Outcome: Participants successfully report the entire row of $4$ letters if the auditory beep cue occurs quickly enough after grid offset.

  • Comparison and Interpretation:

  • Partial report accuracy is significantly higher than full report accuracy.

  • Participant introspection: Participants report seeing the entire grid clearly in their mind, but state that the representation fades away rapidly as they begin reporting the items.

  • The nature of the information store is revealed by the specific type of partial report cue used.

Short-Term Memory (STM) Rules, Capacity, and the Gateway Hypothesis

• Operating Principles of Short-Term Memory ($\text{STM}$):

  • Duration: Unrehearsed information persists in $\text{STM}$ for no more than $30\,\text{s}$.

  • Capacity: Limited to holding between $3$ and $7$ items ($3-7$ items).

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