Milner (1966)

Uses: Localisation of function / Multistore model of memory / study design (case study)

AIM: To test and observe HM in his daily life using tests and tasks to determine and develop an understanding of the effect which the surgery by Scoville have had on HM. (for more information on HM check main localisation page)

Method: Case study

Procedure:

  • The study is longitudinal over 50 years.

  • Milner conducted psychometric testing such as IQ testing.

  • Directly observed HM's daily behaviour

  • She conducted interviews with HM and his families.

  • She tested HM's memory recall skills and learning skills.

  • In particular, understand the mirror task. HM was required to complete the mirror task, which is an activity where he is unable to see his hand but can see it and the piece of paper through a mirror. His task is to draw the pattern inside the shape on the paper by not looking at it directly but through a mirror. This continued for 3 days straight and HM’s ability improved over time. Showing he has the ability of generating procedural memory but not declarative memory.

Result:

  • HM is incapable of learning new episodic knowledge and new semantic knowledge.

  • However, he can create new cognitive spatial memory and procedural memory.

  • He also has working memory, however he forgets everything.

  • HM’s intellegence did not change after the surgery and his intellegence remained stable.

Conclusion:

HM is incapable of learning new knowledge but he is able to cognitively form knowledge and use working memory. However, he can not retain these working memories afterward. This shows the role of the Hippocampus is for creating new declarative memory and learn new episodic and semantic knowledge. Spatial memory and short term working memories are not affected by the absence of the hippocampus. IQ also doesn't change after the removal of hippocampus and skills such as eye hand coordination can still be learnt by HM. This in the theory of localisation of function shows the hippocampus is mainly used for creating new declarative memory and they are used to learn new episodic and semantic knowledge.

Evaluation:

  • Pros:

    • Use of case study - multiple research methods. Triangulation (use of multiple methods, eg observation, interviews with HM's family, psychometric testing, IQ testing.)

    • Ensured Consent - but due to severe memory loss it could be questionable as to whether this is true consent.

    • Longitudinal, 3 days of mirror drawing in a roll…

  • Cons:

    • Done entirely by a single person, may have made mistakes along the way.

Scoville, W. B., and B. Milner. "Loss Of Recent Memory After Bilateral Hippocampal Lesions." Journal of Neurology, Neurosurgery & Psychiatry 20.1 (1957): 11-21.