Milner (1966)

Aim

to understand the link between the hippocampus and memory

Background information

• Henry Molaison (HM) suffered an accident, aged 7, resulting in a serious head injury

• started to suffer from epileptic seizures, aged 10

• couldn't control bodily functions due to seizures, aged 27

• medication did not help

• had an experimental surgery by neurosurgeon, William Scoville

• tissue from temporal lobe was removed, including hippocampus

Procedure

Method triangulation

• Psychometric testing

• Direct observation of HM’s behaviour

• Interviews with both HM and family members

• Cognitive testing

• MRI Scans

Findings

• retrograde amnesia (memory of events before operation) diminished

• anterograde amnesia (memory of past decade) diminished

• unable to form episodic knowledge and new semantic knowledge

• retained spatial memories

• had a capacity for working memory

• procedural memories (motor skills) maintained

Conclusion

• hippocampus plays a critical role in converting short-term memory into long-term memory

• short-term memory and long-term memory uses different brain region

• implicit memory contains several stores

Strengths

1. Longitudinal study

2. High ecological validity

3. Utilisation of method triangulation reduces research bias and enhanced validy of results

Weaknesses

1. Difficult to replicate + limited generalisation (case study)

2. Retrospective elements limited availability of pre-accident cognitive data

3. Potential confounding effects of epilepsy medication on brain damage

4. Lack of control variables in naturalistic setting may introduce confounding factors