Assupmtions of biological psychology

• Biological approach


  Combines psychology and biology to provide physiological explanations for human behaviour
• 3 assumptions of the biological approach

  • Evolutionary influences
  • Localisation of brain function
  • Biochemicals and neurotransmitters
• Evolutionary influences


  • Change of a species over time
  • Charles Darwin
• Darwin's theory of natural selection

  1. Only a small proportion of each generation survives to reproduce

  2. Offspring are not identical to their parents, and so each generation has a degree of variation, and at least some of this variation is heritable (can be passed on through genes)

  3. Some characteristics give the animal an advantage over others in the ability to survive and reproduce
• Adaptive characteristics


  Characteristics which give the animal a greater chance of survival and reproduction
• If a characteristic has survived and been passed down through the generations, it must have been adaptive and have given the animal a survival advantage
• Predisposition to fear of snakes and spiders

  Snakes and spiders are poisonous and can kill with one bite, so people who are predisposed to avoid these animals are less likely to get bitten and die, and therefore survive longer and be more likely to reproduce, passing these genes on to their offspring
• Men prefer young rather than old women, women with wide hips and narrow waists, and women with full lips and large eyes


  Full lips and large eyes are signs of youth, and younger women are more fertile. Narrow waists and wide hips are also signs of fertility and health.
• To understand functions of brain, we must understand environment in which brain evolved - the environment of evolutionary adaptedness (EEA), which is the environment that our ancestors would have faced
• Hemispheres


  The two halves of the brain

  
• There are roughly 100 billion neurons in the brain and spinal cord
• Broca's area is the main language center of the brain, associated with the production of speech and written language, as well as being linked with the processing and comprehension of language. Damage to Broca's area may result in difficulty formulating words and written language.
• Wernicke's area is important for the comprehension of language, and is located in the upper temporal lobe. Damage to Wernicke's area may result in difficulty understanding language, although the person may still be able to speak fluently.
• Broca's area and Wernicke's area are close in proximity, typically in the left hemisphere of the brain, and are connected to each other via a neuronal tract called the arcuate fasciculus.
• Hormones


  Chemicals that travel around the body in the blood
• Neurotransmitters


  Chemical substances that transmit nerve impulses across a synapse
• Behavioural characteristics are caused by our genes, which we inherit from our parents. The biological approach says that people inherit a disposition to behave in a certain way.