Biological Approach

• evolution refers to the change over successive generations of the genetic makeup of a particular population
• natural selection is the process by which inherited characteristics that enhance an individuals reproductive success are passed on to the next generation and so become more widespread
• heredity is the passing of characteristics from one generation to the next through genes
• heritability is the amount of variability in a trait within a population that can attributed to genes
• a gene is a part of the chromosome of an organism that carries information in the form of DNA
• a genotype is the genetic makeup of an individual. the genotype is a collection of inherited genetic material that is passed from generation to generation
• the phenotype is the observable characterisitcs of an individual. this is a consequence of the interaction of a genotype with the enviroment
• the central nervous system is a connected system that processed, interprets and stores information and issues orders to muscles and glands. the CNS includes the brain and the spinal cord
• the peripheral nervous system is a connected system that transmits information to and from the CNS comprising of the somatic and autonomic nervous system
• neurochemistry is the study of chemical and neural processes associated with the nervous system
• a neuron is a nerve cell
• a neurotransmitter is a chemical that communicates information from one neuron to another
• assumption 1:

  humans are viewed as biological beings, and it is expected that behaviour can be explained using references to biology
• assumption 2:

  there is a genetic basis to behaviour, behaviour is inherited
• assumptions 3:

  behaviour can be explained through the structure and function of the human nervous system
• evolution and natural selection are important, human genes have evolved over millions of years to adapt behaviour to the enviroment, therefore behaviour will have an adaptive/ evolutionary purpose
• behaviours will be passed on to offspring and will become more widespread in the population, through the process of natural selection
• example of evolutionary approach

  bowlby suggest attachment is innate and biologically programmed into babies

  infants seek proximity and develop one dtrong emotional bond with the mother early on during critical period to meet the biological needs of an infant and aid the infants survival
• • biological preparedness explains many phobias do not develop because of a traumatic incident
  • people are more likely to develop phobias of 'ancient fears' which would have been a threat to our ancestors
• human examples of evolution include:

  • facial expressions to signal emotional states such as smiling for happiness
  • territorial behaviours such as fighting to defend resources
  • development of physical structures to support human language abilities
• non human example of evolution:

  • before the industrial revolution peppered moths were much lighter in colour
  • due to industrial pollution the lighter coloured moths were easier for predators to see
  • the darker moths survived and reproduced
• differences between genotype and phenotype:

  • phenotype includes enviroment influences as well as genes, genoype is strictly a persons genetic makeup
  • genotype is fixed whereas phenotype is more malluable
• examples of genetics and behaviour:

  MZ twins

  • identicle twins share indenticle DNA but may show differences in their phenotype due to enviroment factors

  PKU

  • inherited genetic disorder
  • whether the effects are expressed is due to the enviroment
  • effects can be overriden by dairy free diet
• the brain consists of two hemispheres and four frontal lobes
• at the back of the brain below the occipital lobe is the cerebellum
• hemispheres in the brain are connected by nerve fibres called the corpus callosum
• hemispheric lateralisation refers to the idea that certain functions are principally governed by one side of the brain
• localisation of function is the idea that certain functions have certain locations in the brain
• influence of neurochemistry on behaviour:

  • neurotransmitters are essential for the transmission of nerve impusles across the synapse
  • chemical processes in the brain are responsible for many different aspects of psychological functioning
  • an imbalance of certain chemicals in the brain may cause abnormal behaviours and thoughts
• schizophrenia:

  • an increase in neurotransmitters dopamine is thought to be responsible for the positive symptoms of schizophrenia
  • low dopamine in the frontal parts of the brain may be the cause of negative symptoms of schizophrenia
• evaluation 1:

  approach uses scientific methods, this enhances the scientific credibility of the approach and use of scientific methods helps to establish psychology as a science
• evaluation 2:

  biochemical processes in the brain has led to the development of psychoactive drugs to treat depression and schizophrenia, this can alleviate symptoms and improve quality of life~
• evaluation 3:

  biological approach is deterministic, human behaviour is governed by internal or genetic causes over which we have no control

  if a 'criminal gene' were discovered, behaviour is biologically determined and not due to free will so this raises the question