The foundations of a human life are laid down during pregnancy and the first two years of life. During this time the ‘social brain’ is shaped, a period in which the emotional style and resources of an individual are developed. The social brain is the part of the brain that learns how to manage feelings and relate with others. The stress and immune responses also develop during this time and impact the future emotional life of the individual. Emotional systems are shaped by early parenting, but also by the wider culture and society in which this parenting happens. When these influences are less than optimal, social and emotional problems can arise later in life.

Science is beginning to recognise that feelings form the core of the human personality. Rationality and thinking are built on top of this feeling foundation. The rational part of the brain does not work alone but at the same time as the emotional parts of the brain. Cognitive processes (thinking) build on emotional ones and cannot exist without them.

Each cell in our body has around 30,000 genes. Only a small amount of these are active at any time. These genes are stimulated into action by the environment – they do not express themselves in a vacuum. Even having ‘really good genes’ does not determine how successful we will be or what we will be good at. A set of genes has a number of potential futures and which ones get ‘turned on’ depends on what happens in the environment. For example, a diet of one type of food will stimulate one set of genes while a different diet will activate others. Our social and emotional experiences arouse biochemical processes that activate genes in determining who we become.

The period from conception through the first two years is probably the most important period of development. This is roughly 1000 days in which the nervous system is being shaped by experience. How the parents relate to the child during this period has as much impact as genes on how the child will develop. The way the parents respond will teach the baby about her own emotions and how best to manage them. How we learn to deal with our feelings will impact how our behaviour and thinking capacities develop later. The impact of these early years are not forgotten. As William Faulkner once wrote, ‘The past is not dead. It is not even past’. These experiences stay present with us, forming the background to our adult lives. The constitute the core of the self. As the poet Wordsworth said, ‘The child is father to the man’.

Life begins as egg and sperm connect and the fertilised cell finds a home in the mother’s womb. After conception the developing embryo and the mother collaborate to create the placenta. The placenta acts as a protective barrier which prevents anything toxic in the mother’s system from reaching the embryo. Nutrients, oxygen and hormones also cross this divide to nourish the embryo. If the mother’s lifestyle is relatively healthy the placenta can do its job effectively. However, if there is drug-use this function can be compromised.

During this period the foetus is doing what has been called ‘weather forecasting’. This means she is building up assumptions about what life ahead will be like. If the mother is well nourished the foetus will assume that they are entering a life of plenty. If she is not they may start to adapt to a more barren environment by storing lots of calories in order to survive.

We all begin life a part of another person. As such we have been involved in every experience of their life. Our mother’s subjective life – her moods and emotions are passed onto us through her hormonal responses. These hormones, as Thomas Armstrong says, set the thermostat on our ‘emotional climate control’. We experience the inner version of sunny days and thunderstorms.