Biological approach

• An imbalance of neurochemicals in the brain has been implicated as a possible cause of mental illness (e.g. low levels of serotonin in OCD)
• Twin studies are used to investigate whether certain psychological characteristics have a genetic basis. This is achieved by analysing concordance rates- the extent to which twins share the same characteristic.
• Genotype= genetic make-up
• Phenotype= the characteristics of an individual determined by both genes and the environment.
• Biological approach= emphasises the importance of physical processes in the body
• assumptions= all thoughts, feelings and behaviour ultimately have a physical basis.
• Fight or flight

  Hypothalamus activates the pituitary gland and this triggers activity in the sympathetic branch of the autonomic nervous system. The ANS changes from its normal resting state (parasympathetic state) to the physiologically aroused sympathetic state.
• Fight or flight


  Adrenaline is released from the adrenal gland into the bloodstream. Adrenaline triggers physiological changes in the body (e.g. increased heart rate) which creates the physiological arousal necessary for the fight or flight response.
• Fight or flight

  All of this happens immediately and automatically as soon as the threat is detected. This is an acute response and an automatic reaction in the body.
• Fight or flight

  Once the threat has passed, the parasympathetic nervous system returns the body to its resting state. The parasympathetic branch of the ANS works in opposition to the sympathetic nervous system.
• Endocrine system= one of the body’s major information systems that instructs glands to release hormones directly into the bloodstream. These hormones are then carried to target organs.
• Fight or flight= increased heart rate, increased breathing rate, dilated pupils, inhibits digestion, inhibits saliva production and contracts rectum.
• Evaluation

  Increased understanding of neurochemical processes in the brain is associated with the use of psychoactive drugs to treat mental disorders (antidepressants increase levels of serotonin at synapses in the brain). This means that people with depression can better manage their condition and live a relatively normal life.
• Evaluation

  Antidepressant drugs do not work for everyone. Study by Cipriani compared 21 antidepressant drugs and found wide variations in their effectiveness. This challenges the biological approach because it suggests that brain chemistry alone may not account for all cases of mental disorders like depression.
• Evaluation

  In order to investigate the genetic and biological basis of behaviour, the biological approach makes use of a range of precise and highly objective methods (e.g. fMRIs and EEGs). With advances in technology it is possible to accurately measure physiological and neural processes in ways that are not open to bias. This means that much of the biological approach is based on objective and reliable data.
• Evaluation

  The biological approach, however, is determinist- it sees human behaviour as governed by internal, genetic causes over which we have no control. However, we have already seen that the way in which an individuals genotype is expressed (phenotype) is heavily influenced by the environment. Not even identical twins look and think the same. Also, a purely genetic argument becomes problematic when we consider things like crime. This suggests the biological approach is often too simplistic and ignores the effects of the environment.
• Concordance rates = the degree of genetic similarity for a particular trait
• Imbalance of neurotransmitters can cause changes in behaviour and in some cases mental disorders. (e.g. imbalance of serotonin is associated with depression and an imbalance of dopamine is associated with schizophrenia).