A fear of maths may be partly caused by genes and not just by pupils' experiences in school, a new study has found.
Genetic factors are responsible for about 40 per cent of the variance in maths anxiety, according to research involving pairs of twins. Fear of sums can affect people of all abilities, academics point out in the report, leading to lower grades and avoidance of situations involving maths.
Previous investigations into maths anxiety have focused on the impact of early experiences of success and failure, but the latest study is the first to investigate a possible genetic cause.
Although the study shows that the majority of the difference in anxiety between children is down to their own experiences, it also suggests that some children may be predisposed towards developing the problem.
The study, published in The Journal of Child Psychology and Psychiatry, compares 216 identical twins and 298 same-sex non-identical twins aged 12.
Mathematical anxiety was measured by asking the twins 26 questions about maths-related activities - such as adding up the cost of buying several items - and asking how they felt about them on a scale of 1 (not at all nervous) to 5 (very nervous). They were also asked about their general anxiety, and were given mathematical problem-solving and reading comprehension tests.
As well as suggesting that there is a genetic component, the results indicate that the environmental factors that contribute to anxiety around maths are child-specific rather than shared (in the same family, for example). This suggests that identifying individual rather than general solutions could help teachers to help students.
Professor Robert Plomin, of King's College London's Institute of Psychiatry, is one of the joint authors of the study, led by Dr Zhe Wang of Ohio State University in the US. "This paper means that people differ in their levels of mathematics anxiety and some of those differences are due to genetic differences," Professor Plomin said. "That means that some people are slightly more predisposed to it. These are genetic nudges in a direction - it is not hard-wired and deterministic.
"What it is in the environment which influences maths anxiety is very hard to explain exactly. It could be very idiosyncratic experiences. If a child is laughed at, just one episode like that can have an effect and that experience would not have been shared by the other twin."
He added that the paper did not support the idea of a maths "gene" that determines whether people can do maths.
Research by the Programme for International Student Assessment, which ranks countries by the mathematical achievement of their 15-year-olds, has found that students who believe that hard work leads to good results perform up to a year ahead of those who think mathematical ability is innate.
Dr Sue Pope, chair of the general council of the Association of Teachers of Mathematics, said: "There's quite a lot of evidence that the way mathematics is experienced can influence pupils' attitudes and self-belief. Being put into sets, so some pupils think they are not any good at maths, can have a negative effect and becomes a self-fulfilling prophecy."
Lynn Churchman, lead consultant with the charity National Numeracy, said: "There are four areas in which we think successful teachers can build self-belief in pupils. The first is in creating a classroom ethos that encourages taking risks, so children know they will not be ridiculed if they get something wrong. The second is by giving children challenging work - sometimes teachers protect anxious children by not giving them challenging work, but the children get bored and think that they are given simple tasks because the teacher has no belief in them.
"Teachers can also give children a chance to do rough work first and ensure that assessment is not just a bare 210 but contains comments about how to become more successful."