Transcranial Electrical Stimulation and the Enhancement of Numerical Cognition

Transcranial electrical stimulation (tES) is being employed as a tool for cognitive enhancement in an increasing number of research studies. Its effects have been noted in a range of psychological functions, including numerical cognition and learning. This chapter first presents the historical background, technical principles, and limitations that contextualize modern tES experiments, and then considers how this technology has been applied in the enhancement of numerical cognition. The populations considered here include individuals with normal numerical abilities, such as judging numerosity, perceiving and comparing magnitudes, and carrying out more advanced arithmetic operations, as well as individuals with serious difficulties in working with numbers, as seen in mathematics anxiety and developmental dyscalculia. The chapter concludes with a consideration of important directions that research may take in the future. The emphasis throughout is the need to test the ecological validity of tES-induced cognitive benefits, which is particularly important in the context of an ever-increasing number of positive reports, both in the media and in academia. However, enhancements in healthy individuals have been restricted entirely to controlled laboratory settings. The essential bridge between using tES to enhance numerical cognition in the laboratory and the enhancement of mathematical achievement in educational or occupational settings has yet to be built. As this chapter illustrates, the steady accumulation of evidence is providing firmer ground to begin explorations of the ecological validity of tES interventions.