Biological Approach

• The 3 main assumptions:

  • The genes inherited determine behaviour
  • The biological structures affect behaviour
  • The neurochemistry of the body influences behaviour
• What is Genotype?

  The genetic makeup of an individual. A collection of inherited genetic material that is passed from generation to generation.
• What is Phenotype?

  The observable characteristics of an individual. This is the result of the interactions of the genotype with the environment
• The nervous system is comprised of several connect systems:

  • Neurons: individual nerve cells that carry messages in the body
  • Central Nervous System (CNS): brain and spinal cord
  • Peripheral nervous system (PNS): somatic and autonomic NS.
• What are hormones?


  Chemicals produced in the endocrine glands. The gland secrete hormones directly into the bloodstream as a reaction to a signal from the brain. Hormones can alter the activity of cells (such as the neurons) provoking a physiological / biological change.
• What are neurotransmitters?


  Chemicals in the brain that carry messages which affect behaviour. This is done via the synapses. Some neurotransmitters are excitatory (dopamine) and some are inhibitory (serotonin).
• The genes inherited determine behaviour:

  • Genes can carry instructions for a particular characteristic
  • How this characteristic develops also depends on the interaction with other genes as well as influence on environment
  • Genotype and Phenotype.
• The biological structures affect behaviour:

  • The nervous system is comprised of several connect systems, PNS and CNS
  • The brain (neurostructures)
• 4 brain lobes:

  • frontal
  • temporal
  • parietal
  • oscipital
• The brain is divided in: cerebrum, cerebral cortex, right and left hemispheres (each divided in 4 lobes)
• The cerebrum is 85% of the brain.