HM was diagnosed as suffering with anterograde (inability to form new memories due to impairment of moving data from STM to LTM) & retrograde amnesia (person’s pre-existing memories are lost to conscious recollection but can form new memories).
In 1953, Hm aged 27 had brain surgery to alleviate the severe symptoms of epilepsy by removing parts of his hippocampus. This led to him only remembering partial events after age of 16 and almost nothing after 25.
His STM remained the same but couldn’t make new LTM, shared no knowledge of current affairs & forgot stuff as soon as he read it. Knew nothing of moving house, his Father’s death, knew people from long time but forgot new people.
Researchers conducted interviews with HM over many years and provided qual data regarding cog abilities. When he died his brain was given to psychologists to map his brain. Milner conducted a case study on Hm gathering data & assessed recall of salient personal events with reports of HM being ‘dimly aware of his Dad’s death’.
He was unable to describe his work place but could create a plan of his house. Conducted neurological examinations to asses any neurological change & co-ordination & motor power.
Before his Op his IQ was 104, 2 years later it was 112. Could do sorting & perceptual tasks, completed face perception by recognising faces from black & white patterns & having to guess age & sex. Hm matched control group of 8 & was superior.
Hm tested on public events & showed little awareness of national & international events; he was able to recall present Kennedy from a half dollar & knew he was assassinated.