IB Psychology Higher Level

The brain and behaviour

Understanding the Biological Approach to Behaviour through the Brain

The Brain's Structure

• The brain is divided into distinct regions, each playing a key role in our behaviour.
• The frontal lobe is associated with problem solving, reasoning, decision making, and planning.
• The parietal lobe controls spatial awareness, touch sensation, and object manipulation.
• Emotions, memory processing, and the flight or fight response are managed by the limbic system, which includes the amygdala and hippocampus.
• The occipital lobe is primarily responsible for vision and visual perception.
• The temporal lobe handles auditory processing and is also crucial for memory formation.

Neurotransmitters and Behaviour

• Neurotransmitters are chemicals that transmit signals through neurons. Different neurotransmitters have different effects on behaviour and mood.
• For instance, the neurotransmitter dopamine is associated with reward and pleasure, and its abnormal levels are linked with conditions like Parkinson’s disease and schizophrenia.
• Serotonin regulates mood, appetite, and sleep. Low levels of serotonin are linked with depressive disorders.
• Acetylcholine plays crucial roles in memory and learning. Reduced levels of this neurotransmitter are found in Alzheimer's disease patients.

Brain Plasticity

• Neuroplasticity or brain plasticity refers to the brain's ability to reorganise itself by forming new neural connections throughout life.
• Neuroplasticity allows neurons to compensate for injury or disease and to adjust their activities in response to new situations or changes in the environment.
• Increased activity or stimulation can cause the brain to strengthen its connections, while decreased activity can cause the connections to weaken or disappear - a phenomenon known as use-dependent plasticity.
• Neurogenesis, the process of producing new neurons in the brain, also contributes to the brain's plasticity.

Hormones and Behaviour

• Hormones are chemical messengers released by glands in the body, having significant effects on behaviour and emotions.
• Cortisol, the stress hormone, can affect memory, immune function, and the likelihood of developing mental illnesses.
• Oxytocin, often referred to as the love hormone, promotes bonding and trust.

Genetics and Behaviour

• Behavioural genetics studies the genetic and environmental influences on behaviour.
• Twin studies often used to estimate the heritability of a trait or behaviour. Identical twins share 100% of their genes, making them ideal for such research.
• Adoption studies are also used to determine the influence of genetics versus environment on the development of certain behaviours or psychological traits.