Schmolck et al (2002)

• Contemporary study - Schmolck et al. (2002):

  Semantic knowledge in patient HM and other patients with bilateral and lateral temporal lobe lesions.
• Schmolck et al. (2002) AIM:

  To investigate the effects of damage to the medial temporal lobe (MTL) (middle of the temporal lobes)and anterolateral temporal cortex (front and side of the temporal lobes) on semantic knowledge.
• Schmolck et al (2002) IV (participants):

  6 amnesia patients were divided into groups depending on the level of brain damage suffered.

  2 patients - damage only to the hippocampal formation (HF)

  3 patients had medial (Situated in the middle...) temporal

  lobe lesions with damage to the anterolateral (To the front and side of...) temporal cortex (MTL+)

  HM had a bilateral medial (Situated in the middle) lobe lesions temporal lobe resection for severe epilepsy
• Schmolck et al (2002) SAMPLE:

  All patients suffered bilateral damage to varying degrees.

  8 controls - matched on age (74 years old), sex (male) and education (12.4 years).
• Schmolck et al (2002) SAMPLE DESIGN:

  Since the IV is naturally-varying and the Controls were matched on age and education, this is a natural experiment with matched pairs design.

  It means we can be reasonably sure that the different scores on the tests were caused by the brain lesions in different parts of the brain, not by age or intelligence.
• Schmolck et al (2002) DV:

  Scores on 9 separate tests of semantic LTM, over 3 to 5 sessions.

  Designed to measure semantic knowledge related to identifying, sorting or defining the line drawings.

  
• Schmolck et al (2002) DESIGN:

  Schmolck used different types of cognitive tests on the patients. The type of cognitive test is a repeated measures design because each participant did every test.
• Schmolck et al (2002) PROCEDURE:

  For tests 8 + 9, a tape recorder was used and the definitions were then transcribed.

  Each pts performance was measured using the number of correct statements and the number of inaccurate statements. Schmolck et al also gave a quality score between 0-4 to each definition.

  To assess the reliability of the 0-4 scoring, 14 raters had to try to identify from the transcripts of test 8 what items were being defined. They were then asked to score each on the scale of 0-4.
• Schmolck et al (2002) RESULTS:

  
• Schmolck et al (2002) CONCLUSIONS:

  There was a positive correlation between the amount of brain damage and the number of mistakes.

  The MTL+ patients made the most mistakes, followed by HM, then the hippocampus-only patients.

  MTL+ Patients damage is consistent with a loss of semantic knowledge.There seems to be a clear link between damage to the temporal cortex generally and the loss of semantic LTM.
• Schmolck et al (2002) CONCLUSIONS:

  Patients with damage specific to the hippocampus suffered loss of episodic memory, but not semantic memory.This suggests that semantic and episodic LTM are encoded in different parts of the brain, with the hippocampus/MTL dealing with episodic memory and the nearby anterolateral temporal cortex dealing with semantic memory.
• Schmolck et al (2002) FINDINGS FOR HM:

  H.M. performed similarly to the Controls but with odd lapses when it came to defining things, where he resembled the MTL+ group more.

  This suggests H.M. had very specific brain damage that wasn't quite like the others. However, there are problems with generalising from H.M. because of his unusual background. H.M spent most of his young life with debilitating epilepsy and his entire adult life in hospitals, being studied by psychologists.
• Schmolck et al (2002) GRAVES: Generalisability

  Brain damaged patients are not representative of the wider

  population so findings about the role of the brain regions in semantic knowledge such as lesions to the MTL+ may not be generalisable to all human memory. Therefore the findings of Schmolk could be considered limited.
• Schmolck et al (2002) GRAVES: Generalisability

  it is not possible to generalise to the whole population from a few case studies because each involves unique circumstances. It may be that the individual being researched is not typical of the population. For example, all of the participants in Schmolk’s study have atypical brains. HM had brain surgery to remove his hippocampus whilst other participants had damage to the MTL+ which were destroyed due to a virus.
• Schmolck et al (2002) GRAVES: Reliability

  good example of reliability because it has standardised procedures that could be replicated by other researchers. For example, instructions are presented for each type of test and can be easily followed.

  Also, in Test 8 and 9, Dr Schmolck also used 14 raters to check the participants’ scores and their agreement gives this study inter-rater reliability.
• Schmolck et al (2002) GRAVES: Application

  The main application of this study has been for other Cognitive Psychologists, who have built on Dr Schmolck’s research, and earlier studies involving H.M., to understand the brain’s role in memory.

  The study also helps us understand the risks of brain surgery and the side-effects of brain damage, which would enable doctors and patients to weigh up the risks of surgical procedures. This sort of research may even lead to a cure for patients (like Clive Wearing) with this sort of memory loss if brain lesions can ever be repaired.
• Schmolck et al (2002) GRAVES: Validity

  The use of healthy Controls and the matched pairs design increases the validity of this study. It means we can be reasonably sure that the different scores on the tests were caused by the brain lesions in different parts of the brain, not by age or intelligence.
• Schmolck et al (2002) GRAVES: Ecological Validity

  The ecological validity of this study is not good. Naming and categorizing drawings on cards is more like a game or a puzzle than the sort of memory you need in real life. It is an artificial test.
• Schmolck et al (2002) GRAVES: Ethics

  This study involved patients who could not give valid consent, because they would not be able to remember having the study explained to them. This means the researchers could only obtain presumptive consent from the patients' doctors and carers.

  Ethicists regard it as unacceptable to treat the lack of refusal as tacit consent. (consent given without words) However, the benefits to our scientific understanding of brain functioning from studying patients like H.M. have been so enormous, it may outweigh the lack of consent from these few, unusual patients.