Schmolck's study

full grave table on one note + paper essay plan

What was the aim of Schmolck’s study?

• To investigate if semantic LTM is linked to a particular part of the brain

Who were the participants?

HM:

• hippocampus removed to help with seizures caused by epilepsy.

HF - 2 Pp:

• hippocampus and/or medial temporal lobe damage.

MTL+ 3 Pp:

• medial temporal lobe and temporal cortex damage.

healthy controls - 8 Pp:

• no brain damage, to compare to those with brain damage.

What was the type of design used in this study?

• Matched pairs design - each patient was matched with a health control so exact differences in memory could be established.

• Matched on age + education level.

• So if they were tested on knowledge one could have better memory than the other purely based on education levels.

• They were all matched to reduce extraneous variables

 

What was the procedure in the study and how does it have good inter - rater reliability?

• 9 tests

• 48 drawings - half objects half animals

• grouped in sixes e.g. 6 pics of musical instruments, six pics of dogs.

• category sorting - Pp were given all 48 pictures and asked to sort the theme into ‘living’ or ‘man - made’

• Pp were tape recorded and their responses transcribed.

• 14 raters checked each transcript for reliability. And also looked for grammar/syntax errors as problems with language also indicates trouble with semantic memory.

• increases inter - reliability as 14 same or similar scores increases internal reliability and removes experimenter bias.

What were the results?

HF - hippocampus and/or medial temporal lobe damage

100% accurate

MTL+ - medial temporal lobe and temporal cortex damage

• 78% accuracy

• did the worst on all tests

Healthy controls:

• 99% accuracy

HM:

• did better than MTL+ patients but slightly worse than the HF patients who had damage solely to the hippocampus.

• HM performed similarly to the health controls but with odd lapses when it came to defining things where he resembled MTL + more.

• Suggests he had specific brain damage that wasn’t quite like the others.

Why can HM’s results have problems with generalisability?

• Spent his entire adult life in hospitals being studied by psychologists.

• Lowers the internal validity as he would be naturally better at tasks like this as he has been exposed to them for a great portion of his life.

• Compared to the others who may not have done tasks like these before.

What did Schmolck conclude?

• clear link between the temporal cortex generally and the loss of semantic LTM.

• Patients with damage specific to the hippocampus suffered loss of episodic memory not semantic.

• Suggests semantic and episodic LTM are encoded in different parts of the brain, with the hippocampus/MTL dealing with episodic and the temporal cortex with semantic

• provides credibility to Tulving’s theory - distinct stores in LTM.

What are the key points for generalisability/SAMPLE?

Weakness

A01:

• 14 people, 6 patients

• HM - hippocampus removed

• HF 2Pp - hippocampus and/or medial temporal lobe damage

• MTL+ 3Pp - medial temporal lobe and temporal cortex damage

• healthy controls 8Pp - used for comparison.

A03:

• small sample

• only 3 patients (including HM) with MTL/hippocampus damage and 3 with wider temporal cortex damage.

• samples this small easily distorted by anomalies like HM, however Schmolck singled HM out due to his wider brain damage

• his results were analysed in more detail.

• However, these brain lesions and memory problems are relatively rare

• HM suffered from severe epilepsy, MTL + from herpes

• Makes them unrepresentative of the wider population, so external validity is limited.

What are the key points for validity/MATCHED PAIRS DESIGN?

Strength

A01:

• Each patient matched with a health control so exact differences in memory could be established.

• Matched on age + education level.

• Matched on education level as if they were tested on knowledge one could have better memory than the other purely based on education levels.

A03:

• Increases internal validity, limits extraneous variables.

• can be reasonably sure that different scores on the test were caused by the brain lesions in different parts of the brain and not by age or intelligence.

What are the key points about reliability/PROCEDURE?

Strength

A01:

• 9 tests

• 48 drawings - half object half animals. - grouped in sixes

• category sorting - Pp given all 48 pics and asked to sort the themes into ‘living’ or ‘man made’

• Pp were tape recorded and responses transcribed, 14 raters checked for reliability. Also checked for grammar and syntax errors as problems with language indicate trouble with semantic memory.

A03:

• increases inter - rater reliability as if 14 same/similar scores it increases the internal reliability and removes experimenter bias.

What are the key points about application/REULTS?

Strength

A01:

• HF - 100% accuracy

• MTL+ - 78% accuracy, worst on all tests

• health controls - 99% accuracy

• HM - did better than the MTL+ patients, but worse than the HF who had damage solely to the hippocampus. Performed similarly to the health controls but with odd lapses when it came to defining things

• also a clear link to the damage of the temporal cortex and the loss of semantic LTM.

A03:

• Study helps us understand risks of brain surgery and side effects of brain damage.

• Enables docs + patients to weigh up the risks of surgical procedures.

• e.g. HM may not have agreed to his 1953 surgery if he understood the consequences.

• Fosters psychological knowledge in society - can be applied to real world scenarios.