Do you believe it’s true that the genes a baby has will be profoundly affected by the way it is treated? 

By Alasdair Palmer, 7:00AM GMT 28 Oct 2012 

Take a careful look at the image of two brains in the attachment. The picture is of the brains of two three-year-old children. It’s obvious that the brain on the left is much bigger than the one on the right. The image on the left also has fewer spots, and far fewer dark “fuzzy” areas. 

To neurologists who study the brain, and who have worked out how to interpret the images, the difference between these two brains is both remarkable and shocking. The brain on the right lacks some of the most fundamental areas present in the image on the left. Those deficits make it impossible for that child to develop capacities that the child on the left will have: the child on the right will grow into an adult who is less intelligent, less able to empathise with others, more likely to become addicted to drugs and involved in violent crime than the child on the left. The child on the right is much more likely to be unemployed and to be dependent on welfare, and to develop mental and other serious health problems.

What could possibly cause so radical a divergence in brain development? The obvious answer is that it must have been some illness or terrible accident.

The obvious answer is wrong.

The primary cause of the extraordinary difference between the brains of these two three-year-old children is the way they were treated by their mothers. The child with the much more fully developed brain was cherished by its mother, who was constantly and fully responsive to her baby. The child with the shrivelled brain was neglected and abused. That difference in treatment explains why one child’s brain develops fully, and the other’s does not.

Neurologists are beginning to understand exactly how a baby’s interaction with their mother determines how, and indeed whether, the brain grows in the way that it should. Professor Allan Schore, of UCLA, who has surveyed the scientific literature and has made significant contributions to it, stresses that the growth of brain cells is a “consequence of an infant’s interaction with the main caregiver [usually the mother]”. The growth of the baby’s brain “literally requires positive interaction between mother and infant. The development of cerebral circuits depends on it.”

Prof Schore points out that if a baby is not treated properly in the first two years of life, the genes for various aspects of brain function, including intelligence, cannot operate, and may not even come into existence. Nature and nurture cannot be disentangled: the genes a baby has will be profoundly affected by the way it is treated.

The details of how the chemical reactions that are essential to the formation of new brain cells and the connections between them are affected by the way a mother interacts with her baby are extremely technical. Suffice it to say that there is now a very substantial body of evidence that shows that the way a baby is treated in the first two years determines whether or not the resulting adult has a fully functioning brain. The damage caused by neglect and other forms of abuse comes by degrees: the more severe the neglect, the greater the damage. Eighty per cent of brain cells that a person will ever have are manufactured during the first two years after birth. If the process of building brain cells and connections between them goes wrong, the deficits are permanent.

This discovery has enormous implications for social policy. It explains two very persistent features of our society. One is the way that chronic disadvantage reproduces itself across generations of the same families. There is a cycle of deprivation – lack of educational attainment, persistent unemployment, poverty, addiction, crime – which, once a family is in it, has proved almost impossible to break.

The way that the development of a child’s brain is dependent on the way that the child is treated by its mother explains why this depressing cycle happens. Parents who, because their parents neglected them, do not have fully developed brains, neglect their own children in a similar way: their own children’s brains suffer from the same lack of development that blighted their own lives. They, too, are likely to fail at school, to be liable to get addicted to drugs, to be unable to hold down a job, and to have a propensity to violence.