The brain is where our genes and the environment meet—where nature and nurture interact. Our social setting can affect our brain circuitry and biochemistry, which are also influenced by genetic controls. These neurobiological mechanisms can, in turn, affect behaviour. A lot is known about the molecules, circuitry, and neural networks involved with certain behaviours such as addiction, feeding, stress and reward. This body of knowledge can be used to better inform assumptions and hypotheses when developing new behavioural change interventions.