The present short review discusses reasons for the mixed results on the possible enhancement of cognition, especially executive function, in bilingualism. We define three major problem areas that hamper many studies in this field: the use of research designs that are weak for the task at hand, the lack of a detailed theory on how bilingual experience would modify cognition, and the employment of measures of bilingual behaviour and executive function that are troublesome. Potential remedies for these problem areas are discussed, and the emerging research approach where specific aspects of individual bilingual experience are examined and related to specific aspects of executive performance is highlighted.