The belief that learning the arts helps children with other subjects remains "not proven", according to a report commissioned by government advisers.
The review of 22 research studies found "interesting indications", but the National Foundation for Educational Research report concluded "there is simply insufficient consistent and compelling evidence that arts education will necessarily lead to positive non-arts outcomes".
The findings come at a politically sensitive time as the Qualifications and Curriculum Authority - whose forerunner commissioned the report - is concerned not to become embroiled in the controversy over the Government's relaxing of arts and music teaching in the primary curriculum. It is especially sensitive as the authority is engaged in a major overhaul of the curriculum.
The report also found that there might be an association between some music and the development of space and time skills; certain aspects of arts education might be particularly effective with younger children; the transfer of learning from one subject to another was not easy to achieve; and more research was needed to identify the specific experiences that could enable artistic development.
The review was commissioned following an international conference on the arts and the curriculum last year when delegates discussed the effects of additional teaching in art and music on the progress of children's reading and maths skills.
The NFER team looked at the research in the light of three questions: did each study contain sound evidence of positive effects, and were these likely to have been caused by extra exposure to arts education? Was the research of sufficiently high quality to be sure of the outcomes? If there were positive results from each piece of research, was there sufficient evidence from a number of studies to consider the case proven?
The 22 studies related to four areas: academic achievement, especially in maths, reading and language skills; spatial ability; personal and social outcomes; and thinking skills, creativity, art appreciation.
The authors emphasise that "any debate about the contribution of the arts to the education of children and young people should recognise the intrinsic value of what arts have to offer, above and beyond any possible 'added value' in terms of cognitive, academic, emotional, or social outcomes".
The findings, they say, have been drawn from a relatively small number of studies, evaluating a wide range of initiatives, aimed at different types of children, in different art forms, and using a variety of research designs. "It is hardly surprising that the evidence is inconsistent and even contradictory."
"The effects of teaching and learning in the arts", by Caroline Sharp, Pauline Benefield and Lesley Kendall.