Unit 2: Biological Level of Analysis Session 2

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...


There are three principles that define the biological level of analysis

Can you remember any of them?

A recap of session one


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


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?


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


• 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



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%


What is the difference between monozygotic twins and dzygotic twins?

Which one is which?

New terms?


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


New terms?

Concordance rate?

Longitudinal study?


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.


Explain one study of localisation of function of the brain

Today’s learning outcome


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


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)


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)


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)


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


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?


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.


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



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



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



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)


Only his memory was affected by the removal of the hippocampus

His personality remained unchanged and there was no general intellectual impairment



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.


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.


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.


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



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)



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.



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

Documents

Unit 2: Biological Level of Analysis Session 2