Cognitive approach - Contemporary Study

Question 1

AO1 points on Schmolck et al. (Background on H.M)

Answer 1

• This study was carried out by Dr Heike Schmolck on a group of patients who had all experienced brain damage and loss of memory.
• The most famous patient in the study was “H.M.” (Henry Molaison) who had brain surgery for his epilepsy in 1953 which involved the removal of the hippocampus and suffered amnesia as a result.
• H.M. would recall information so long as it was in his short term memory, but then forgot it within seconds and could not create new episodic memories. However, he still remembered some things from before his brain damage.
• HM has been called the most important patient in the history of brain science. Schmolck wanted to compare H.M. to other patients with similar brain damage to see if a precise link could be made between brain structure and semantic memory.
• H.M. underwent brain surgery in 1953 for his life threatening epilepsy. The surgeon removed a part of the brain called the hippocampus. A side-effect was that H.M. was unable to encode new LTM.
• However, although H.M. lost his episodic memory, he still had procedural memory (such as how to write) and could encode new procedural memories (he learned to play tennis – but he couldn’t remember being taught it).
• There were 14 patients in total. 3 (including HM) had brain damage to the hippocampus (part of the medial temporal lobe or MTL) from surgery or other injuries, 3 had brain damage from viral infections (herpes simplex encephalitis) and their brain damage was more widespread – these were called the MTL+ group. 8 of them were Controls who were healthy volunteers with no brain damage. They were matched with the patients in terms of age (70s) and education.
• Schmolck used matched pairs design. Each healthy Control was matched against a brain-damaged patient. This is important for any experiment with independent groups, but especially natural experiments where the researcher can’t choose how to assign participants to conditions.
• One of the problems with studying “lesions” (damage to parts of the brain) is that patients usually have lesions in several parts of the brain, not just one.
• The patients with viral brain damage had more extensive lesions than the patients (like H.M.) who had received surgery in just one part of the brain, the hippocampus. However, H.M. had more widespread lesions than the other MTL patients, but not as widespread as the MTL+ patients.

Question 2

AO1 points on Schmolck et al. (Aim)

Answer 2

• To find out if Semantic LTM is linked to a particular part of the brain. If so, patients with lesions in that part of the brain should underperform at tests of Semantic LTM. Schmolck focused on damage to the medial temporal lobe (MTL) and the hippocampus and looked in detail at the performance of Patient H.M..

Question 3

AO1 points on Schmolck et al. (Independent Variable)

Answer 3

• The extent of brain injury: (1) 3 patients with damage to Hippocampus/MTL only; (2) 3 patients with damage to MTL and the temporal cortex too (the MTL+ group); (3) a Control group with no brain damage.
• Since the IV is naturally-varying and the Controls were matched on age and education, this is a natural experiment with matched pairs design.
• In addition, 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.
• Since H.M. also had more widespread brain damage than the other Hippocampus/MTL patients (brought on perhaps by his earlier epilepsy, perhaps by the less accurate brain surgery in the 1950s) he was also considered separately from the others.

Question 4

AO1 points on Schmolck et al. (Dependent Variable)

Answer 4

• Scores on 9 separate tests of semantic LTM

Question 5

AO1 points on Schmolck et al. (Sample)

Answer 5

• 14 participants in total
• 6 patients with severe damage to the MTL and 8 Controls with no brain damage. 3 of the patients also had damage to the temporal cortex generally (MTL+).

Question 6

AO1 points on Schmolck et al. (Procedure)

Answer 6

• Schmolck created 9 tests for Semantic LTM functions. All were based on a set of 48 drawings, half of animals and half of objects.
• These pictures were grouped in sixes: 6 land animals, 6 birds, 6 musical instruments, 6 vehicles, etc. Here are some examples:
• Similar pictures: the participants are shown 6 pictures sharing a theme and asked to point out the one that the researcher names (this is testing for confusion caused by semantic similarity – similar to the Baddeley study)
• Category fluency: the participants were asked to give as many examples as possible from each theme within a minute
• Category sorting: the participants were given all 48 pictures and asked to sort them into “living” or “man made”
• Definitions: the participants were shown a picture and asked to define it by the theme it fitted into.
• Schmolck also used additional tests that are used with dementia patients. One of these involved 30 pictures that showed either real objects or non-objects: participants had to say whether the object in the picture was real or not.
• The participants were tape recorded and their responses transcribed (typed up). 14 ‘raters’ checked each transcript for reliability and also looked for grammar/syntax errors in the way the participants spoke because problems with language also indicates trouble with semantic memory.

Question 7

AO1 points on Schmolck et al. (Results)

Answer 7

• Schmolck collected scores for all 9 tests. Here are some examples of her findings:
• Similar pictures: the Controls got all the answers right as did those with hippocampus damage only (H.M. score 98% for living creatures and 100% for objects); MTL+ patients performed worse: 85% for living creatures and 90% for objects
• MTL+ Group: These patients did significantly worse in all the tests (p<0.005)
• Patient H.M.: H.M. did better than the MTL+ patients but slightly worse than the other MTL patients who had damage solely to the hippocampus
• Overall: Controls scored 99%, MTL patients (excluding HM) scored 100% and MTL+ patients scored 78%
• There was also 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
• Where the hippocampus-only patients did better than the Controls, Schmolck suggests it is because they were younger (even though Controls were supposed to be matched on this…).

Question 8

AO1 points on Schmolck et al. (Conclusions)

Answer 8

• There seems to be a clear link between damage to the temporal cortex generally and the loss of semantic LTM.
• 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 temporal cortex dealing with semantic memory.
• 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.
• H.M. had seizures beginning at age 10 (which raises the question whether his language development was fully normal), his schooling was interrupted, and he came from a low socioeconomic background. Any of these factors could be important

Question 9

AO3 Evaluation points of Schmolck et al. (Generalisability)

Answer 9

• Schmolck et al. used a small sample – only 3 patients (including HM) with MTL/Hippocampus damage and 3 with wider temporal cortex damage. Samples this small are easily distorted by anomalies – and H.M. seems to have been the anomaly here.
• However, Schmolck did single H.M. out as an anomaly because of his wider brain damage. The researchers analysed H.M.’s results in more detail.
• These brain lesions and memory problems are relatively rare. H.M. suffered from serious epilepsy. The MTL+ patients all suffered from herpes. This might make them unrepresentative of the wider population.

Question 10

AO3 Evaluation points of Schmolck et al. (Reliability)

Answer 10

• This is a good example of a reliable study because it has standardised procedures that could be replicated by other researchers. MRI scans are becoming common.
• Schmolck also used 14 raters to check the participants’ scores and their agreement gives this study inter-rater reliability.
  Nonetheless, the participants themselves are hard to replicate. HM died in 2005, so no more studies can be carried out on him.

Question 11

AO3 Evaluation points of Schmolck et al. (Application)

Answer 11

• The main application of this study has been for other Cognitive Psychologists, who have built on Schmolck’s research, and earlier studies involving H.M., to understand the brain’s role in memory.
• This is leading to the development of neurocognitive psychology i.e. a mixing of the Cognitive and Biological approaches.
• 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 (HM might not have agreed to his surgery in 1953 if the consequences had been understood).
• In the future, 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.

Question 12

AO3 Evaluation points of Schmolck et al. (Validity)

Answer 12

• 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.
• This is backed up by the MRI scans which showed the temporal lobe area activating when patients had to make semantic judgements.
• However, the ecological validity of this study is not good. Naming and categorising 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.
• Other studies (eg Teng & Squire) asked these patients to recall the neighbourhoods they grew up in and found they performed well at that.

Question 13

AO3 Evaluation points of Schmolck et al. (Ethics)