Lecture 1 Notes: Memory

Memory Lecture 1

Dr. Fiona McNab, Department of Psychology, University of York (fiona.mcnab@york.ac.uk).

Overview of Lectures

• Lecture 1: Structure of memory
• Lecture 2: Structure of memory
• Lecture 3: Working memory
• Q&A session: Tuesday 29th April at 10am on Zoom. Watch 2 videos before the Q&A!
• Lecture 4: Memory Training – Is it effective?
• Tutorial: False Memory

Reading Material

• Baddeley, A. D., Eysenck, M. W., & Anderson, M. C. (2015). Memory. Hove and New York: Psychology Press.
• Quinlan, Philip T; Dyson, Ben (2008). Cognitive psychology. Harlow : Pearson Prentice Hall
• Papers - see VLE and my email

Assessment

• What will be asked?

Learning Objectives

• Demonstrate knowledge of influential models of memory and their possible short-comings.
• Demonstrate knowledge of experimental work that may support / contest these models.
• Demonstrate knowledge of classic memory phenomena.
• Demonstrate knowledge of recent debates in memory research.
• Demonstrate an appreciation of various experimental methodologies that have been used in memory research.

Why is Memory Important?

• Examples: Shopping lists, remembering names.
• Imagination: Recalling events, recalling previously imagined events, constructing imagined events. Overlap in brain activity (Hippocampus).
• From Hassabis et al. (2007), see Mullally, S. and Maguire, E.A. (2014) The Neuroscientist, 20(3), 220-234

Encoding vs. Retrieval

• Encoding: Converting information into a usable form.

• Storage: Holding this information in memory.

• Retrieval: Taking memories out of storage.

• Maintenance/delay period.

• Patient HM could retrieve long-term memories from before surgery but could not create new long-term memories.

  • Retrograde amnesia: Loss of memory-access to events that occurred, or information that was learned, before an injury or the onset of a disease.
  • Anterograde amnesia: Loss of the ability to create new memories after the event that caused the amnesia.

• HM's amnesia suggests a distinction between encoding and retrieval.

Short-Term vs. Long-Term Memory

• HM retained short-term memory and procedural memory.
• This supports a distinction between short-term and long-term memory stores and suggests that there is not a single global memory system.

Capacity of Short-Term vs. Long-Term Memory

• Miller (1956): The magical number seven, plus or minus two: some limits on our capacity for processing information. Psychological Review, 63:81–97
• Standing (1973): Participants shown up to 10,000 pictures selected from magazines were able to recognise those seen previously with a 83% accuracy. Standing, L. (1973). Learning 10000 pictures. Quarterly Journal of Experimental Psychology, 25, 207-222.

Sensory Memory

• Sperling (1960)

• $50 \, ms$

• $1000 \, ms = 1 \, second$

• $50 \, ms = \frac{1}{20} \, of \, a \, second$

• How many items can be remembered?

• About 4.5 items

• A perceptual limit?

• The magical number seven, plus or minus two - the span of immediate memory (Miller, 1956).

• Full report: report everything

• Partial report: reported a sub-set of items, which are cued

• Partial report superiority Didn’t know which row to report in advance, so nearly all the items must have been remembered

• Visual stimuli - iconic memory

• Auditory stimuli - echoic memory

• Touch stimuli - haptic memory

• What is held in sensory memory?

  • The items and their positions.
  • Partial report advantage for all physical characteristics.
  • No partial report advantage when asked to report items of a certain category eg. letters or digits (Sperling, 1960).

• Sensory memory as a copy or "mental photograph"

• Large capacity

• Pre-categorical,

• Time span?

• Sperling (1963)

• Sensory memory

  • Large capacity
  • Pre-categorical
  • Very brief time span, is it always ½ a second?

• Sperling (1963)- Light, Time

• Visual/pattern masking

  • Visual noise mask
  • Forward mask
  • Backwards mask
  • Interruption masking:
    • Replacement
    • Curtailment

• The mask influences visual processing after information from the two eyes has been combined into a single percept.

• Coltheart (1972) Visual masking

• Quinlan & Dyson (2008) pages 77 - 80

• Is iconic memory more than visual persistence?

• Summary of sensory memory

  • Full-report v partial report,
  • Partial report superiority,
  • High capacity and transient form of memory,
  • Apparently pre-categorical,
  • Apparently more than visual persistence.

Broadbent (1958) memory model

• Three systems (stores):
  • “S-system” (sensory memory, unlimited capacity)
  • “P-system” – limited capacity, items processed serially and can be fed back to the S-system (rehearsal)
  • Long term memory.
• Forgetting:
  • For short-term memory, items are lost by decay,
  • For long-term memory, items are lost by interference.

The Modal Model

• Short-term versus long-term memory.
• These components are “horizontal faculties” – ie. the same memory constraints apply to visual, auditory, haptic etc. stimuli.
• Control processes regulate the flow of information between the stores.

Unitary Models

• Models that unify mechanisms of short- term and long-term memory.

Fragile VSTM

• Abstract
• People often rely on information that is no longer in view, but maintained in visual short-term memory (VSTM).
• Traditionally, VSTM is though to operate on either a short time-scale with high capacity – iconic memory – or a long time scale with small capacity – visual working memory.
• Recent research suggests that in addition, an intermediate stage of memory in between iconic memory and visual working memory exists. This intermediate stage has a large capacity and a lifetime of several seconds, but is easily overwritten by new stimulation. We therefore termed it fragile VSTM. In previous studies, fragile VSTM has been dissociated from iconic memory by the characteristics of the memory trace. In the present study we dissociated fragile VSTM from visual working memory by showing a differentiation in their dependency on attention. A decrease in attention during presentation of the stimulus array greatly reduced the capacity of visual working memory, while this had only a small effect on the capacity of fragile VSTM. We conclude that fragile VSTM is a separate memory store from visual working memory. Thus, a tripartite division of VSTM appears to be in place, comprising iconic memory, fragile VSTM and visual working memory.

Serial Order Effects

• Free recall
• Serial order task
• Serial position curve:
  • Primacy effect
  • Recency effect
• Murdock (1962) Different list lengths, Different rates of presentation.
• Glanzer & Cunitz (1966)
  • 0 = Immediate recall after the list ended.
  • 10 = 10 seconds of counting backwards after the list ended.
  • 30 = 30 seconds of counting backwards after the list ended.
• Problems with this account
  • Bjork & Whitten (1974)
    • manipulated rehearsal for different items, but still saw a primacy effect
    • there was a number distractor task at the end of the list, but still saw a recency effect.
  • Long-term recency effects eg. Baddeley & Hitch (1977) They also found that memory decreased as the number of intervening matched increased (it wasn’t determined by the time since the match)
• Distinctiveness accounts
• Quinlan & Dyson (2008) pages 370 - 374

Decay / Rehearsal

• Broadbent (1958): Forgetting:
  • For short-term memory, items are lost by decay.
  • For long-term memory, items are lost by interference.
• Brown (1958)
  • Pairs of consonants to remember, then read the pairs of numbers for 5 seconds, then recall the pairs of consonants.
  • Pairs of consonants to remember, then wait for 5 seconds, then recall the pairs of consonants.
• Peterson & Peterson (1959) “The Brown – Peterson Task”: To examine forgetting when rehearsal is prevented by an irrelevant task
• Decay occurs even when the number of items is well below the immediate memory span ($7 \pm 2$ chunks)
• Keppel & Underwood (1962)
  • Backwards counting for 3 or 18 seconds
  • Six “trials”

Interference

• Proactive interference: The negative influence of old material on new material.
• Retroactive interference: The negative influence of new material on old material.
• Release from proactive inhibition
• Wickens, Born & Allen (1963) Switching the category of the items (eg. letters to digits) improved memory performance.
• Waugh and Norman (1965) A greater contribution from interference than delay. $4s \, 1s$
  $3s \, 12s$
• Broadbent (1958) Forgetting:
  • For short-term memory, items are lost by decay,
  • For long-term memory, items are lost by interference. Not supported

Summary

• The modal model – multi-store model.
• Serial order effects.
• Support for the short-term versus long-term distinction?
• Decay
• Proactive interference
• Interference versus decay – support for a greater contribution of interference than decay in short- term memory.