Unit 2:Biological Level of
AnalysisSession 2
‘All that is psychological is first physiological’
Unit 2: Biological LOA
Lab report draft submission
Drafts will be returned with feedback on Friday
Final report due Monday 4th March
First things first...
Unit 2: Biological LOA
There are three principles that define the biological level of analysis
Can you remember any of them?
A recap of session one
Unit 2: Biological LOA
1. There are biological correlates of behaviour
2. Animal research can provide insight into behaviour
3. Human behaviour is, to some extent, genetically based
Three Principles of Biological Level of Analysis
Unit 2: Biological LOA
1. There are biological correlates of behaviour
2. Animal research can provide insight into behaviour
3. Human behaviour is, to some extent, genetically based
How are these principles demonstrated in research?
Unit 2: Biological LOA
Newcomer et al. (1999) Performed experiment on the role of stress hormone cortisol on
verbal declarative memory
Participants listened to a prose paragraph and had to recall is as a test of verbal declarative memory
Group 1 showed worst performance on task Shows that an increase in cortisol has a negative effect on
memory
1.) There are biological correlates of behaviour
Group 1 (high dose) Group 2 (low dose) Group 3(control)
Tablets containing 160mg of cortisol for 4 days
Tablets containing 40mg of cortisol for 4 days
PlaceboTablets
Unit 2: Biological LOA
• Phineas Gage• Iron rod blew threw his
skull and he turned into a jerk
• Shows that behavior has a physiological basis (his personality changed)
• Shows there are biological correlates of behavior (after his frontal lobe was damaged he lost his ability to restrain himself)
1.) There are biological correlates of behaviour
Rozenweig and Bennet (1972) Performed experiment with rats Wanted to study role of environmental factors on brain plasticity
Rats spent up to 60 days in their respective environments before being killed
Brains of rats in group 1 showed a thicker layer of neurons in the cortex than group 2
Shows that brain grows more neurons if stimulated
2.) Animal Research can provide insight into human behaviour
Group 1 Group 2
Enriched environment- lots of toys
Deprived environment- no toys
Unit 2: Biological LOA
Unit 2: Biological LOA
Bouchard et al. (1990) Minnesota Twin Study Longitudinal study investigating role of genes in
IQ**
Shows a link between genetic inheritance and intelligence but does not rule out the role of environment
3.) Human behaviour is, to some extent, genetically based
Identical twins reared apart Identical twins reared together
Concordance rate of IQ of 76% Concordance rate of IQ of 86%
Unit 2: Biological LOA
What is the difference between monozygotic twins and dzygotic twins?
Which one is which?
New terms?
Unit 2: Biological LOA
Monozygotic and Dzygotic Twins
MZ twins are identical twins They are from the same egg and share 100% of
their genes DZ twins are fraternal (non-identical) twins They develop from two separate eggs and
share 50% of their genes They are no more alike than normal siblings If there is a genetic basis to behaviour, MZ twins should show a higher concordance rate
Unit 2: Biological LOA
New terms?
Concordance rate?
Longitudinal study?
Unit 2: Biological LOA
New terms?
Concordance rate: the statistical measure of similarity between twins. A higher % of concordance indicates a bigger similarity
Longitudinal study: A study that takes place over a long period of time. Can be weeks, months or years.
Unit 2: Biological LOA
Explain one study of localisation of function of the brain
Today’s learning outcome
Unit 2: Biological LOA
Not long after the case of Phineas Gage, two psychologists made some interesting discoveries when looking at stroke victims
Broca (1861) Wernicke (1874)
Localisation of Brain Function
Unit 2: Biological LOA
Found that people suffering from damage to their left frontal lobe of the brain were unable to make grammatically complex sentences
Area of the brain eventually came to be called Broca’s area
Broca’s patients had problems producing speech, but were able to understand it
This condition is now know as Broca’s aphasia
Paul Broca (1861)
Unit 2: Biological LOA
Broca used a case study to support his claims
His most famous patient was a young man named Tan
He was called Tan because that’s the only word he could say
After his death, an autopsy revealed the source of his brain damage and led to the idea that the disability was the result of a specific brain trauma.
Paul Broca (1861)
Unit 2: Biological LOA
First described the area that appears to be crucial for language comprehension
The left posterior superior temporal gyrus Wernicke’s patients could produce speech,
but could not understand it This condition is known as Wernicke’s
aphasia
Carl Wernicke (1874)
Unit 2: Biological LOA
The research undertaken by Broca and Wernicke provides us with a clear understanding of some of the factors involved in language processing
By carrying out post-mortem studies of people who had suffered from strokes, they came to the conclusion that language processing is localised
Broca and Wernicke
Unit 2: Biological LOA
When a behaviour is localised in the brain, it is possible to trace the origin of a behaviour to a specific part of the brain
Studies in localisation of function led to the desire to map out the brain’s functions
Though localisation does not explain all human behaviour, the mapping out of the brain was an important step forward in brain research
Localisation?
Unit 2: Biological LOA
Important because it provided evidence that there are different memory systems in the brain
Milner (1957) was first to report case of H.M. and memory function after H.M. Had an operation which removed the hippocampus and adjacent areas in his brain
The case study of H.M.
Unit 2: Biological LOA
Suffered from epileptic seizures after he fell of his bike aged seven
It was assumed his seizures were related to his accident
He became increasingly incapacitated
The case study of H.M.
Unit 2: Biological LOA
When he was 27, a neurosurgeon performed experimental surgery to stop the seizures
Tissue from the medial temporal lobe, including the hippocampus, was removed
After the operation H.M. suffered from amnesia
He could recall information acquired in early life, but was unable to form new memories
The case study of H.M.
Unit 2: Biological LOA
H.M. suffered from anterograde amnesia (failure to store memories that happened AFTER a trauma)
He was unable to remember the faces of new people he met
He could carry out normal conversations, but would not remember people he met after the operation
He could read and re-read the same magazine without realising that he had read them before
The case study of H.M.
Unit 2: Biological LOA
Did an MRI scan* of H.M.’s brain Brain imaging was used because it allowed
researchers to get a precise image of the brain damage
They were then able to identify where the damage was i.e. the removal of the hippocampus
*MRI-Magnetic resonance imaging- a type of brain scanning technique
Corkin et al. (1997)
Unit 2: Biological LOA
Only his memory was affected by the removal of the hippocampus
His personality remained unchanged and there was no general intellectual impairment
The case study of H.M.
Unit 2: Biological LOA
The hippocampus and areas around hippocampus play a critical role in converting memories of experiences from short-term to long-term memory
H.M. could retain memories of what happened BEFORE the surgery. This indicates that the hippocampus is a temporary rather than a permanent memory stories
H.M. could learn a few new procedural* memories which indicates that procedural memories are not stored via the hippocampus
*procedural memory: memory for skills, actions and actions- “knowing how”
What can be learned about localisation of brain from H.M.
Unit 2: Biological LOA
The fact that H.M. (and other people with amnesia) had deficits in one part of the memory but not in others is evidence that the brain has several memory systems and that these are supported by distinct brain regions
Shows that memory processes are much more complex than originally believed
Although hippocampus is very important in the storage of new memories it is not the only part of the brain involved in the process
What can be learned about localisation of brain from H.M.
Unit 2: Biological LOA
Strengths Surgery was based on assumption that
H.M.’s seizures would stop and it was successful in this respect
H.M. participated in research for more than 50 years and participated in many kinds of tests including cognitive tasks, observations and neuroimaging studies
Evaluation of case of H.M.
Unit 2: Biological LOA
Strengths This longitudinal case study has
contributed enormously to knowledge of how memory processes are related to specific areas of the brain:
The hippocampus is important for the forming, organising and retrieval of memories
Procedural memories are not processed by the hippocampus
Evaluation of case of H.M.
Unit 2: Biological LOA
Limitations: Ethical Considerations Although the surgery stopped the seizures it
caused memory problems that had not been anticipated.
Since H.M. was unable to remember all the times he participated in research, it could be argued that it was unethical. However, the findings of the study are very important which justifies it. (remember the ends must justify the means)
Evaluation of case of H.M.
Unit 2: Biological LOA
Limitations As this was a case study it is questionable
whether the results can be generalised to a larger population
HOWEVER... Findings from other case studies of people
with brain damage like H.M. tend to support these findings so it may be possible to generalise the findings to some extent.
Evaluation of case of H.M.
Unit 2: Biological LOA
One entry pre session in back of book May just be on topic already covered Might be new topic/research based Doesn’t have to be in full sentences, as long
as content is clear
Today: Outline the three principles of the biological
process noting a demonstration of each
Psychology Journal