Schmolck et al. (2002)

Schmolck et al. (2002)

1. ABOUT

   • AIM
     • To find out if Semantic LTM is linked to a particular part of the brain
   • IV
     • The extent of brain injury
   • DV
     • Scores on 9 separate tests of semantic LTM
   • SAMPLE
     • 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+)
   • METHODS
     • A natural experiment with matched pairs design.
     • The type of cognitive test is a repeated measures design because each participant did every test.

2. PROCEDURE

   • 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.
   • EXAMPLES OF THE 9 TESTS
     • Category sorting: the participants were given all 48 pictures and asked to sort them into “living” or “man made”
     • Category fluency: the participants were asked to give as many examples as possible from each theme within a minute
   • The participants were tape recorded and their responses transcribed (typed up).
     • 14 'raters' checked each transcript for reliability
     • They ooked for grammar/syntax errors in the way the participants spoke because problems with language also indicates trouble with semantic memory.

3. RESULTS

   • MTL+ Group: These patients did significantly worse in all the tests
   • There was a positive correlation between the amount of brain damage and the number of mistakes.
   • H.M. did better than the MTL+ patients but slightly worse than the other MTL patients who had damage solely to the hippocampus

4. CONCLUSION

   • 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,

5. EVALUATION

   • GENERALISABILITY
     • Only a small sample was used which means results can easily be distorted by anomalies
   • RELIABILITY
     • It has standardised procedures that could be replicated by other researchers.
     • 14 raters to check the participants’ scores and their agreement gives this study inter-rater reliability.
   • APPLICATION
     • Helps us understand the side-effects of brain damage on memory
   • VALIDITY
     • Lacks ecological validity as tasks are artificial
   • 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.