The Biological Approach

• Biological approach

  Assumes everything psychological was first biological and so to understand human behaviour we have to look at the biological structures within them
• Genotypes

  • 23 pairs of chromosomes that individuals are born with, inherited from biological parents
• DNA

  Carries instructions for our characteristics
• Genetics influence behaviour

  e.g. intelligence is inherited in the same way that height is
• Investigating genetic influence

  1. Twin studies

  2. Concordance rates analysis
• If a characteristic is genetic, it would be expected that all MZ twins would share the characteristics as they share 100% of their genetics
• McGuffin et al. (1996)


  • 46% chance if one twin had depression, that the other twin would also have it
• This suggests there is a genetic component to illnesses such as depression
• Biological approach

  • Deterministic, meaning it sees everything is pre-determined by genetics and biological structures
  • Ignores the effects the environment has on development
• Biological approach

  • Has many real-world applications, such as the success of drug therapies, like antidepressants, in treating psychological disorders
• Biological psychologists

  Recognise the importance of biological structures and neurochemistry in the body and the role it plays in behaviour
• Endocrine system

  A chemical messaging system that operates throughout the body
• Endocrine system


  Releases hormones into the bloodstream
• Pituitary gland

  • Controls the release of hormones from other glands
  • Known as the master gland
• Adrenal gland

  • Releases adrenaline/noradrenaline as part of the fight/flight response
• Reflex arc

  A collection of cells that transmit information
• Sensory neurons


  • Send information from the senses e.g. touching a hot radiator, to the brain e.g. pulling hand off the radiator
• Relay neurons

  • Connect with other neurons
  • Analyse sensations
  • Decide which response to make
  • Act between sensory and motor neurons
• Motor neurons

  • Send messages from axons in neurons to the muscles
• Synapse

  Found at the end of the cell<|>Synaptic transmission allows neurons to communicate by passing chemical signals/messages between them
• Neurotransmitters

  Chemical messengers released at the synapse
• Excitatory neurotransmitters

  • Increase the likelihood of a new action forming in the postsynaptic cell
  • Cause depolarisation
• Inhibitory neurotransmitters

  • Decrease the likelihood of a new action forming in the postsynaptic cell
  • Cause hyperpolarisation
• Synapse transmission

  1. Action potential travels down the axon of the presynaptic neuron

  2. Vesicles containing neurotransmitters merge with the cell membrane and release neurotransmitters into the synaptic cleft

  3. Receptors on the postsynaptic neuron's dendrite membrane detect neurotransmitters, changing the chemistry of the postsynaptic neuron

  4. If the change passes a threshold, a new action potential is triggered and the message is passed on

  5. Neurotransmitters detach from receptors and return to the presynaptic cell via transport proteins (reuptake)
• Nervous System

  The collection of nerve cells that sends electrical messages around the body
• Central Nervous System

  • Contains the brain and spinal chord
  • Receives information, processes it and makes decisions
• Peripheral Nervous System


  • Sends information across the body to the brain
  • Sends decisions from the brain to the body
• Brain

  • Different regions perform different tasks for the body (localisation of brain function)
• Brain Stem

  • Connects the brain to the spine and rest of the body
  • Regulates basic functions such as breathing, heart rate, eating and sleeping
• Temporal Lobe


  • Controls hearing/auditory perception
  • Controls speech comprehension, processing sounds and noise to speech
• Frontal Lobe

  • Predicts future consequences
  • Linked to executive control e.g. not acting on impulses, thinking, reflecting
• Cerebellum

  • Receives information from the spinal cord, sensory systems and other parts of the brain
  • Regulates balance and motor movements
• Cerebral Cortex

  • Largest area of the brain
  • Controls cognition, perception, consciousness, memory, attention, awareness, thought and language
• Occipital Lobe


  • Processes visual stimuli, such as colour, orientation and shape
• Parietal Lobe

  • Regulates sensory information from across the body
• Biological Approach assumptions

  Everything psychology is at first biological:

  • This refers to factors such as genes, neurochemistry and bio-structures that can explain how the mind works and behaviour
  • ‘The mind lives in the brain’

  
• More on Assumptions

  THE INFLUENCE OF GENES: inherited directly from our parents and known as heredity. They determine what are cells develop into such as bone, skin or heart muscle.

  BIO-STRUCTURES: the arrangement or organisation of parts to form an organ, system or living thing. In terms of explaining human behaviour the brain structures and the endocrine system.

  NEUROCHEMISTRY: relating to the chemicals in the brain that regulates psychological functioning such as serotonin and dopamine
• The genetic basis of behaviour

  Nestadt et al (2010) carried out a quasi experiment and his aim was to review twin studies investiagting the genetic basis fro OCD.

  He reviewed two control groups (monozygotic and dizygotic) and measured the concordance rates of each group:

  MZ - 68%

  DZ - 31%

  If identical the MZ twins are found to have higher concordance rates than the non-identical rwins (DZ). This suggests a genetic basis because MZ twins have 100% of each others genes whereas DZ twins share about 50% (like any sibling)
• What is a genotype?

  Genotype is the genetic makeup of the genes in a person (non-observable)
• What is a phenotype?

  Phenotype is the way in which genes are expressed through physical, behavioural and psycological characteristics (observable).