Biological Flashcards
Key Features
1) To understand human behaviour we must look to biological structures & processes within the body, e.g. genes & neurochemistry.
2) From the bio approach, the mind lives in the brain - meaning that all thoughts, feelings & behaviour ultimately have a physical basis - Whereas cognitive approach sees mind as separate from the brain.
Neurochemical Basis of Behaviour
1) NC refers to the action of chemicals in the brain - neurotransmitters transmit messages.
2) An imbalance of neurotransmitters may be a cause of some mental disorders, e.g. underproduction of serotonin in OCD.
Genetic Basis of Behaviour
1) Psychological characteristics (e.g. intelligence) are inherited.
2) Twin studies are used to investigate genetic influences.
Concordance rates between twins are calculated - the extent to which twins share the same characteristic.
3) Higher concordance rates among identical (monozygotic) twins (genetically 100% the same) than non-identical (dizygotic) twins (about 50% the same) is evidence of a genetic basis.
Gottesman - Twin Studies
1) A meta-analysis of European twin studies over a long period of time.
2) Found there was a 48% concordance rate in MZ twins and a 17% concordance rate in DZ twins.
Conclusions:
1) As MZ twins share 100% genes, this would suggest that behaviour has a genetic basis.
–> However, the concordance rate is not 100%, so other factors must also play a part.
Gottesman Evaluation
Strengths:
1) Lots of data from a large number of studies, so reliable.
Limitations:
2) Twins share the same environment and MZ twins more likely to be treated the same.
Genes & Alleles
1) A single gene may have different variations, known as alleles. E.g. can cause blue eyes or green eyes.
2) When a sperm and egg fuse, each parent contributes half the genetic information carried by the offspring –> the physical characteristics of the offspring (their phenotype) are determined by the genetic material from their parents (their genotype).
Genetics & Behaviour
1) Genes affect our physical characteristics - basic personality traits, sexual orientation, temperament and a number of psychological disorders, such as depression and schizophrenia.
2) Genes provide a biological blueprint for our cells, tissues, organs, and body and have significant impact on our experiences and our behaviours.
Genotype & Phenotype
1) Genotype - their genetic make-up.
2) Phenotype - the way that genes are expressed through physical, behavioural and psychological characteristics.
3) The expression of genotype (phenotype) is influenced by environmental factors e.g. phenylketonuria (PKU) is a genetic disorder that can be prevented by a restricted diet.
—> Suggests that much of human behaviour depends on the interaction of nature and nurture.
Genetic Variation
1) The genetic difference between individuals is what contributes to a species’ adaptation to its environment.
Theory of Evolution
1) Darwin proposed the theory of natural selection —> Any genes that enhance survival and reproduction will be passed on to future gens.
2) Such genes are described as adaptive and give the possessor and their offspring advantages.
E.g. attachment behaviours in newborns promote survival and are therefore adaptive and naturally selected.
Evolutionary Psychology
1) Seeks to explain psychological traits as survival-enhancing adaptations.
2) They predict the outcome of a behaviour in a particular situation based on evolutionary theory and then conduct experiments to determine whether the results match the theory.
3) Evolution can make predictions for memory, relationships, friendship, parenting and status.
Strength
IRL APPLICATION - DRUG THERAPY
1) Understanding of neurochemical processes in the brain has led to the use of drugs to treat mental disorders.
2) E.g. drugs that treat clinical depression increase levels of the neurotransmitter serotonin at the synapse and reduce depressive symptoms.
—> Means ppl with depression are able to manage their condition and live a relatively normal life, rather than being confined to hospital.
Strength
USES SCIENTIFIC METHODS
1) In order to investigate both genetic and neurochemical factors, the bio approach makes use of a range of precise & objective methods.
2) Including scanning techniques (e.g. fMRI), which assess bio processes in ways that aren’t open to bias.
—> Means that the bio approach is based on objective and reliable data.
Limitation
DETERMINISTIC
1) Bio explanations tend to be determinist since they see human behaviour as governed by internal, genetic causes over which we have no control.
2) However, phenotype is heavily influenced by the environment. Not even genetically identical twins look and think exactly the same.
—> Suggests that the bio view is too simplistic and ignores the mediating effects of the environment.
Brain Scanning - Maguire et al.
1) Using an MRI scanner, the researchers calculated the amount of grey matter in the brains of taxi drivers and a set of control participants.
Results:
2) The posterior hippocampi of taxi drivers were significantly larger than controls and posterior hippocampal volume was positively correlated with the amount of time they had spent taxi driving.
Conclusion:
This demonstrates brain plasticity. The structure of the brain can change in response to the demands placed upon it.
