SCOVILLE & MILNER (1957)
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THE H.M. CASE STUDIES
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In the 1962 case study, Milner asked H.M. to copy a five-pointed star by drawing between the lines of a template. However, H.M. could only see the reflection of the star and his hand in a memory. This made the task difficult. As with the maze task, Milner asked H.M. to re-attempt the task many times, to see if he grew more skilled at the procedure even though he didn't remember doing it before.
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Other tests were carried out on H.M.. For example, the effect of reinforcement and punishment was investigated, to see if mild electric shocks would help H.M. to remember correct answers. Later, under the direction of Suzanne Corkin, brain scanning technology was used to improve our understanding of H.M.'s condition.
Results
H.M. forgot all new experiences after about 30 seconds; however he remembered a lot of information from before his sixteenth birthday. His personality was consistent, he had good language skills and an above-average IQ. His perception was normal, except for his ability to identify smell, which was very poor.
H.M.loved to describe clear memories of his childhood, over and over, though he lacked a context for them (like how long ago they happened). The face he saw in the mirror surprised himself. Every time H.M. met Milner (and later, Corkin), he introduced himself as if they had never met before, and told his stories again.
H.M. had a knowledge of past events (the Wall Street Crash, World War II). H.M. could not explain where he lived, who cared for him, what he ate for his last meal, what year it was, who the president was, or even how old he was. In 1982, he failed to recognize a picture
of himself that had been taken on his 40th birthday in 1966.
However, he did acquire some knowledge from after his operation: he knew what
an astronaut was, that someone named Kennedy was assassinated and he learned what rock
music was. He learned how to play tennis, although he could not remember being taught the skills and denied that he knew how when asked.
H.M. forgot all new experiences after about 30 seconds; however he remembered a lot of information from before his sixteenth birthday. His personality was consistent, he had good language skills and an above-average IQ. His perception was normal, except for his ability to identify smell, which was very poor.
H.M.loved to describe clear memories of his childhood, over and over, though he lacked a context for them (like how long ago they happened). The face he saw in the mirror surprised himself. Every time H.M. met Milner (and later, Corkin), he introduced himself as if they had never met before, and told his stories again.
H.M. had a knowledge of past events (the Wall Street Crash, World War II). H.M. could not explain where he lived, who cared for him, what he ate for his last meal, what year it was, who the president was, or even how old he was. In 1982, he failed to recognize a picture
of himself that had been taken on his 40th birthday in 1966.
However, he did acquire some knowledge from after his operation: he knew what
an astronaut was, that someone named Kennedy was assassinated and he learned what rock
music was. He learned how to play tennis, although he could not remember being taught the skills and denied that he knew how when asked.
Over 252 attempts, H.M. never showed any improvement in the maze task.
However, H.M.did show improvement in the star-tracing task, making fewer mistakes on each attempt. He started with 30 errors, dropping to 20 on his second attempt and 10 by his seventh. Moreover, he kept these skills from one day to the next, getting better and better at it: on Day 2 he started making only 25 mistakes, immediately dropping to fewer than 10; by Day 3, he was making fewer than 5 mistakes each time. |
Attempts to test punishment with electric shocks had to be abandoned. H.M. possessed huge tolerance for electric shocks, barely noticing shocks that normal people found quite painful. He also seemed to have difficulty noticing feelings of tiredness and hunger.
Conclusions
Milner's qualitative data shows a clear difference between short term and long term memory. They suggest that the hippocampus plays a vital role in transforming short term memories into long term memories, because this was something H.M. (whose hippocampus had been removed in the operation) couldn't do.
Conclusions
Milner's qualitative data shows a clear difference between short term and long term memory. They suggest that the hippocampus plays a vital role in transforming short term memories into long term memories, because this was something H.M. (whose hippocampus had been removed in the operation) couldn't do.
H.M.'s poor ability to identify smell may be linked to the fact that the olfactory bulb - which processes smell - is located close to the hippocampus. H.M.'s poor response to pain and confusion over hunger and tiredness probably links to the damage to his amygdala, which also explains his calm response to the situation he found himself in.
Milner's quantitative data and the later qualitative data suggests a more complex structure for memory.
H.M. did not improve at the maze task because, when he figured out the correct route through the maze, he immediately forgot it. However, he got better at the star task, despite forgetting his previous attempts. Later in life, he learned to play tennis. This suggests H.M. remembered skills even if he forgot events.
H.M. also remembered some items of general knowledge (the moon landings, the Kennedy assassination), even though he couldn't remember the events taking place.
Milner termed this sort of memory "unconscious memory", but Eron Tulving later termed it procedural memory (skills) and semantic memory (general knowledge).
H.M. did not improve at the maze task because, when he figured out the correct route through the maze, he immediately forgot it. However, he got better at the star task, despite forgetting his previous attempts. Later in life, he learned to play tennis. This suggests H.M. remembered skills even if he forgot events.
H.M. also remembered some items of general knowledge (the moon landings, the Kennedy assassination), even though he couldn't remember the events taking place.
Milner termed this sort of memory "unconscious memory", but Eron Tulving later termed it procedural memory (skills) and semantic memory (general knowledge).
EVALUATING THE H.M. CASE STUDIES AO3
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EXEMPLAR ESSAY
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