STUDIES - Milner (1966) or HM Flashcards

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1
Q

Introduction

A
  • Longitudinal case study

HENRY MOLAISON (HM):

  • Hit by a cyclist when child and had serious head injury
  • After injury, developed epilepsy
  • When older, epilepsy was very severe and couldn’t maintain normal life as he didn’t respond to medication
  • Neurosurgeon performed experimental surgery where he removed his hippocampus
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2
Q

Aim

A
  • Better understand the effects that the surgery had on patient HM
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3
Q

Procedure

A

Method:

  • Case study
  • Used triangulation: Direct observation, interviews, MRIs…

Variables:

  • No variables as it was not an experiment
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4
Q

Results

A
  • IQ and personality intact
  • Significant anterograde amnesia: Could not form new explicit memories like semantic or episodic
  • No retrograde amnesia: Had access to memories prior to surgery (LTM), but it got worse as years passed
  • Unable to transfer information from STM to LTM
  • Had working memory: He was able to carry out a normal conversation
  • Could create procedural memory: Showed progress in reverse mirror drawing
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5
Q

Findings

A
  • Hippocampus plays a critical role in transferring information from STM to LTM
  • STM is not stored in hippocampus: Could retain information for a while if rehearsed
  • LTM is not stored in hippocampus: Could remember events prior to surgery
  • Different memory types (procedural, semantic, episodic…) are found in different brain areas: Lost semantic but not procedural for example
  • Biological evidence that STM and LTM are located in different areas of the brain
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6
Q

Evaluation - Strengths

A
  • Longitudinal (<50 yrs): Allowed
    1) Change to be observed over time
    2) Usage of different methods (triangulation)
    3) Formation of rich explanations
  • High ecological validity: No variables manipulated as HM. was observed in his natural environment
  • High ethical standards: Informed consent, no deception, withdrawal from participation
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7
Q

Evaluation - Limitations

A
  • Low replicability: Hard to falsify due to its focus on one specific patient
  • Sample bias: Patient was a male of a certain age, doesn’t allow generalisability to different genders, cultures, or ages
  • Potential researcher bias: Due to longitudinal nature, could have expectations…
  • Retrospective: Little data on HM’s cognitive abilities prior to accident so hard to see what was caused by surgery
    — EXAMPLE: Unaware if medication had caused damage to brain (symptoms from medication or surgery?)
  • Ethical issues: Confidentiality and anonymity was not preserved as we know the name of the patient
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