Null results in bilingualism research

The controversy over whether bilingualism has consequences for mind and brain shows no sign of abating. A steady stream of research reporting both positive results supporting the claim for beneficial effects of bilingualism and null results finding no significant differences between monolingual and bilingual groups continues to be published. With the number of null results that are produced, it is tempting to conclude that the positive effects are not reliable and that there is in fact no effect of bilingualism. However, research results, both positive and null, need to be interpreted in the larger context of factors that describe the experimental paradigm, the linguistic context, and the individual differences of the participants and not reduced to a simple binary question. The present article discusses some of the factors that must be considered in evaluating the interpretation of these research results.