Biological Approach Flashcards
(16 cards)
Main assumption of the biological approach-
All behaviour has a biological root- the importance of genetics
-This approach argues all of our behaviour is shaped by our biology and thus, all behaviour has a genetic basis.
-It suggests that everything psychological has its basis in the biological and therefore, we must look at biological structures such as the brain and CNS, the endocrine system and hormones to understand behaviour
What is the role of genes?
-A gene is the basic unit of hereditary
-It is made up of DNA and occupies a fixed position (locus) on a chromosome.
-Genes provide the information needed to specify potential physical and biological traits
-This approach also argues that genes also shape psychological characteristics such as intelligence, mental illnesses and personalities.
-genetic information is inherited form out parents
What is the influence of genes on our behaviour?
GENOTYPE- an individual’s genetic makeup (the actual genes that we posses)
PHENOTYPE- the physical expression of our genes (the product of the genotype interacting with the environment
Explain how PKU illustrates the relationship between genotype and phenotype.
Despite children carrying the PKU gene in their genotype, their lifestyle (environment) is changed to prevent PKU being expressed in their phenotype.
A recent study showed that Alzheimer’s disease may be partly inherited.
John’s father suffered from Alzheimer’s disease. John is keen to get genetically tested to see if he will develop Alzheimer’s disease.
Explain why John’s genotype will not reveal whether he will suffer from Alzheimer’s disease. 4m
-the genetic test will tell us the genotype, not the phenotype.
-genotype will only reveal his set of genes
-John’s genotype may tell us that he has a gene that makes him more predisposed to develop Alzheimer’s (not that he will definitely suffer)
-environmental factors may contribute to the disorder
Describe twin studies
-psychologists explore the role of genetics in behaviour by carrying out twin studies.
-They use twin studies to determine whether particular behaviours have a genetic basis
What are the two types of twins?
-Monozygotic twins- identical twins (from one egg so they have identical genotypes)
-Dizygotic twins- non identical twins (share 50% genes)
What is the concordance rate?
The % of cases in which both members of a pair have the same attribute (higher concordance= more similar)
Describe the relationship between DZ/MZ twins and genetics disorders.
• The likelihood of MZ both having a behaviour/disorder compared with the likelihood of dizygotic (DZ or non-identical) gives an indication of how much the behaviour may be genetic.
• We would expect that if a trait or illness had a genetic basis that there would be a higher concordance rate in MZ twins than DZ twins.
• If MZ twins both have higher rates of an ability e.g. drawing or a condition, e.g. depression, than DZ , it would suggest a genetic basis
-this is because MZ twins ave higher concordance rates and therefore they share more of their genes.
Describe the influence of biological structures on behaviour (the brain).
The outer layer of the brain is known as the cerebral cortex
The brain is subdivided into two hemispheres
Each hemisphere consists of 4 lobes
Each lobe is thought to be responsible for different functions.
This is known as localisation theory.
If a function is controlled by only one hemisphere this is known as lateralisation theory.
Deeper in the brain there are other structures such as the hippocampus argued play a significant role in memory and learning.
Each of these examples illustrates how the biological approach believes that structures influence behaviour
Describe neurochemistry.
• Chemicals in the brain- neurotransmitters and body-hormones- are said to be related to behaviour and influence our reactions to our environment for example our hormones.
What are hormones?
Hormones are part of the endocrine system which consists of a gland which makes hormones. They are transported around our body in our bloodstream. They are chemical messengers that help to produce changes in our body (produce changes relatively slowly).
E.G. adrenaline is a hormone produced by the adrenal glands
What are neurotransmitters?
Neurotransmitters are found in our nervous system. they are found at the synapse (the junction between nerve cells). Their function is to help pass messages through nerve cell by electrical impulses. This communication is really fast.
What is evolution?
• Evolution is the very gradual change in inherited traits of a species over many generations, via adaptation to the environment, natural selection and survival of the fittest.
What did Darwin theorise?
• In summary, Darwin theorised that within a given population, specific traits are more helpful than others when it comes to the survival of the species. This is referred to as natural selection.
• Traits that increase the chance of survival are more likely to be genetically passed on to future generations. This creates a process where undesirable traits are more likely to fade over time, while desirable traits carry on strongly.
• For example, at some point, foxes with longer legs were able to escape predators more easily. As the shorter-legged foxes fell prey, only the long-legged foxes lived on to reproduce and pass on their genetic characteristics to their offspring. Over time, most or all foxes developed longer legs.
