Milner (1966) Flashcards
Aim
To study the biological reasons for anterograde amnesia (a condition in which a person is unable to create new memories after an amnesia-inducing event) in patient HM.
Procedure
Milner used many different strategies.This is an example of how method triangulation may be used in a case study:
Psychometric testing: IQ testing was given to HM. His results were above average.
Direct observation of his behaviour;
Interviews with both HM and with family members.
Cognitive testing: memory recall tests as well as learning tasks - such as reverse mirror drawing.
Corkin later did an MRI to determine the extent of the damage done to HM’s brain.
Result
HM could not acquire new episodic knowledge (memory for events) and he could not acquire new semantic knowledge (general knowledge about the world). This suggests that the brain structures that were removed from his brain are important for long-term explicit memory.
The researchers also found that he was able to remember his house and could draw a picture of the floor plan of his new home. This indicates that he was able to form a cognitive map of the spatial layout of his house.
HM had a capacity for working memory, since he was able to carry on a normal conversation. This requires a minimal level of retention of what has just been heard and said.
On being asked to recall the number 584, HM was able to do so even 15 minutes later, apparently by means of constant verbal rehearsal. However, after the task was over, the number and HM’s strategy in remembering it were lost.
Memories in the form of motor skills, i.e. procedural memories, were well maintained, for example he knew how to mow a lawn. He also showed improvements on the performance of new skills such as reverse mirror-drawing in which he had to acquire new eye-hand coordination (Milner, 1966).
Findings
The memory systems in the brain constitute a highly specialised and complex system.
The hippocampus plays a critical role in converting memories of experiences from short-term memory to long-term memory.
However, researchers found that short-term memory is not stored in the hippocampus as HM was able to retain information for a while if he rehearsed it.
Since HM was able to retain some memories for events that happened long before his surgery it indicates that the medial temporal region is not the site of permanent storage but rather plays a role in the organisation and permanent storage of memories elsewhere in the brain.
Implicit memory contains several stores - for example, procedural memory, emotional memory and skills and habits. Each of these areas is related to different brain areas.
