- Had brain surgery to alleviate the severe symptoms of epilepsy which involved removal of the hippocampus
- Suffered anterograde (can’t store new memories) and retrograde amnesia (loss of memory of events)
- Retrograde amnesia meant he was unable to retrieve memories from 19 months to 11 years prior to operation (partial memory after 16 but almost nothing after 25)
- Interviews of HM provided qualitative data
- ‘Dimly aware of his father’s death’, unable to describe his work place but could draw a detailed floor plan of his house (semantic)
- Identified the president Kennedy and recalled his assassination (semantic)
- IQ before operation: 104, IQ two years after operation: 112
