Biological Level of Analysis

Biological level of analysis: theory Experiments and studies: Authors and date Kasamatsu and Hirai, 1999

Aim/Research Question How sensory deprivation affects brain?

Martinez and Kesner, 1991

Robert Heath

Rozenzweig and Bennett, 1972

Richard Davidson, 2004

The experiment

Results:

Conclusions

A group of Buddhist monks who went on 72h pilgrimage were studied. During this they didnt consume water or food, or talk, they were exposed to cold weather. After 48h monks began to have hallucinations; blood samples were taken before the ascent and right after reporting hallucinations;

Serotonin levels increased in brain; they activated hypothalamus and frontal cortex.

Sensory deprivation triggered the release of  serotonin, which altered the way monks experienced the world

Determining the role of the neurotransmitter acetylcholine on memory.

Rats-trained Rats-trained to go through a maze; a group of rats were injected with scopolamine (blocking acetylcholine) and another - with physostigmine which increases production of  acetylcholine; the third group was a control one;

The group with more acetylcholine found their way the most quickly; with less acetylcholine - made more errors and was slower.

Acetylcholine plays an important role in memory

The role of nucleus accumbens (pleasure centre) Impact of  environment deprivation and enrichment on brain plasticity Can meditation affect brain activity?

Patients were let to push a button electrically stimulating the nucleus accumbens Rats placed into one of the two environments; enriched - toys; deprived - no toys; 30-60 hours spent and then sacrificed;

Post-mortem studies: stimulating environmentincreased thickness in the cortex. using PET scan an increase in gamma waves in brains of  monks and two volunteers were observed; gamma waves linked to higher reasoning; after meditation gamma waves were still increased only in monks brains  just by watching someone else picking a peanut, monkeys brain acted as if the monkey was carrying out the behaviour

Environment influences dendritic branching.

Gallese et al. (1996)

actually a research on motor neurons; the mechanism of  mirror neurons discovered by accident

Marco Iacobini, 2004

will simply looking at the emotion expressed on human face would cause stimulation of brain

8 Buddhist monks and 10 volunteers trained in meditation for one week; told to meditate for love and compassion;

they isolated the neural response in monkey reaching for a peanut - the electrical electrical signal released a crack every time the monkey reached for the food; but when a researcher reached for a peanut, the crackling noise occurred participants asked to look on human faces while undergoing fMRI; first they had to imitate the faces, then they had to simply watch them

the same areas of  brain were activated in both cases; limbic system was also activated - observing a smiled face activated pleasure centres in brain

meditation can have long-term effects on the brain and way it processes emotions; the brain adapts to stimulation

mirror neurons

mirror neurons in humans

Bouchard and McGue, 1981 Bouchard et al. 1990

IQ correlations between siblings

Scarr and Weinberg (1977); Horn et al. (1979)

IQ and genes

comparison between MZAs and MZTs.; so-called Minnesota Twin Study

Hainer et al. 1988

reviewed 111 studies from around the world; metaanalysis * the most cross-cultural study, longitudinal; each twin completed approximately 50h of testing and interviews; the concordance rated were the highest between MZTs

parents who raised both adopted and natural children; assumption: all children had the same upbringing - any difference of IG correlation depends on genes;

PET scan study

Plomin and Petrill (1997)

the correlations between parent and child IQs

Fessler 2006

an example of  revolutionary research: on disgust; he argued that it allowed our ancestors long enough to produce offspring

496 healthy pregnant women between 18-50 years; asked them to consider 32 potentially stomach-turning scenarios; before asking how disgusted they were, he posed a series of  questions determining whether they experience morning sickness

the closer the kinship the higher the correlation for IQ; concordance rate: same person twice: 87%; MZTs 86%; MZAs 76%; fraternal twins raised together 55%, biological siblings reared together- 47% no significant difference in IQ  correlations-strange as parents came for wealthy, high IQs families and adopted came from poor low IQs families when solving a reasoning problems, individuals with higher IQ had lower metabolic rates than those with a low IQ 

may mean that those with higher IQs use less energy to think; it is known as less effort hypothesis;

between age 4-640% correlation; early adulthood 60%; older adults 80%

correlations between parent and child IQs change over time; it is possible that our genetic disposition pushes us towards environments that accentuate that disposition

women in their first trimester scored much higher across the board in disgust sensivity than those in second and third trimester;

*meta-analysis -it is the statistical synthesis of the data from a set of comparable studies of a problem that yields a quantitative summary of the pooled results.