Image copyright Mass Gen Hospital Image caption Cognitive tests could identify children at the age of three who would go on to become criminals, dependent on welfare or chronically ill

Brain tests at the age of three appear to predict a child's future chance of success in life, say researchers.

Low cognitive test scores for skills like language indicate less developed brains, possibly caused by too little stimulation in early life, they say.

These youngsters are more likely to become criminals, dependent on welfare or chronically ill unless they are given support later on, they add.

Their study in New Zealand appears in the journal, Nature Human Behaviour.

The US researchers from Duke University say the findings highlight the importance of early life experiences and interventions to support vulnerable youngsters.

Although the study followed people in New Zealand, the investigators believe that the results could apply to other countries.

They followed the lives of more than 1,000 children. Those who had low test scores for language, behavioural, movement and cognitive skills at three years old went on to account for more than 80% of crimes, required 78% of prescriptions and received 66% of social welfare payments in adulthood.

It is known that disadvantaged people use a greater share of services. While many of the children in the study who were behind in brain development came from disadvantaged backgrounds, poverty was not the only link with poor futures.

When the researchers took out children below the poverty line in a separate analysis they found that a similar proportion of middle class children who scored low in tests when they were three also went on to experience difficulties when they were older.

Modifiable

The researchers stress that children's outcomes are not set at the age of three. The course of their lives could potentially be changed if they receive support later in life, for example through rehabilitation programmes when they are adults.

Image copyright monkeybusinessimages Image caption Policy makers know the importance of early years education. But the new study suggests that they may have underestimated it.

Prof Terrie Moffitt, from Duke University in North Carolina in the US, who co-led the study, told BBC News: "The earlier children receive support the better.

"That is because if a child is sent off on the wrong foot at three and not ready for school they fall further and further behind in a snowball effect that makes them unprepared for adult life".

Prof Moffitt said nearly all the children who had low scores in cognitive assessments early on in life went on to fall through "society's cracks".

"We are able to predict who these high cost service users will be from very early in life.

"Our research suggests that these were people who, as very young children, never got the chance that the rest of us got. They did not have the help they needed to build the skills they need to keep up in this very complicated and fast-paced economy".

She said society should rethink their view of these people who are often condemned as "losers" and "dropouts" and instead offer more support.

Prof Moffitt conducted the study with her husband, Prof Avshalom Caspi, from King's College London. He said he hoped that the study would persuade governments to invest in those in most need early on in life.

"I hope what our study does is not feed into prejudice," he told BBC News. "I hope that our research will create the public compassion and political will to intervene with children and more importantly offer services to families of children so they can get a better start in life".

Nursery education

Successive governments have invested in expanding nursery education in the UK over the past 20 years. According to Josh Hillman, who is the director of education for the Nuffield Foundation, policy makers already realise the value of early years education.

"But this new research suggests that they may have underestimated its importance," he said.

"The issue now in the UK is to provide more high quality nursery provision and to consider targeting it to those disadvantaged groups that would benefit the most."

Participants were members of the Dunedin longitudinal study, an investigation of the health and behaviour of a representative group of the population of 1,037 people born between April 1972 and March 1973 in Dunedin, New Zealand.

As adults these people account for only 20% of the population - but they use 80% of public services in an analysis of a group of people in New Zealand whose lives were tracked for 40 years.

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