TRENDS/CASES Cognitive abilities that mediate SES’s effect on elementary mathematics learning: The Uruguayan tablet-based intervention Juan Valle-Lisboa 1,2 • A ´ lvaro Cabana 1 • Robert Eisinger 3 • A ´ lvaro Mailhos 1 • Mario Luzardo 1,4 • Justin Halberda 3 • Alejandro Maiche 1 Ó UNESCO IBE 2017 Abstract In unequal societies the effectiveness of formal education depends on the socioeconomic status (SES) of students. Studies have shown that poverty affects the development of the brain in ways that might compromise future learning, thus increasing the differences between groups with different SES. Interest is growing in the development of tools that might change this state of affairs. This article presents a tablet-based study aimed at determining the cognitive abilities related to primary school children’s math learning. The study followed the students’ changes during a short intervention, the purpose of which was to improve students’ performance of some of the core components of mathematical cognition; in particular, of the approximate number system (ANS), a system that supports one’s ability to estimate quantities and to compare time intervals. The article presents the study’s characteristics and shows how the variables that were evaluated—ANS precision, time discrimination accuracy, digit span, and mathematical achievement—de- pend on SES. We employ multiple regressions to show that the variance in mathematics performance attributed to SES can be explained by differences in underlying cognitive factors. The study also indicates that those students of low-SES schools who participated in more tablet activities increased their performance more than students who did fewer activities. Although the intervention’s initial objective was to influence mathematical This work was supported by Centro Ceibal para el Apoyo a la Educacio ´n de la Nin ˜ez y la Adolescencia, Uruguay. We thank Diego Cuevasanta, Cecilia Hontou, Gonzalo Grau, and Leticia Carve for their help in the first 10 days of the intervention. We also thank the principals, teachers, and staff of the participant schools for their help during the study. & Juan Valle-Lisboa juancvl@psico.edu.uy 1 Facultad de Psicologı ´a, Universidad de la Repu ´blica, Trista ´n Narvaja 1674, 11200 Montevideo, Uruguay 2 Facultad de Ciencias, Universidad de la Repu ´blica, Igua ´ 4225, 11800 Montevideo, Uruguay 3 Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA 4 CURE, Universidad de la Repu ´blica, Tacuarembo ´ s/n, Maldonado, Uruguay 123 Prospects DOI 10.1007/s11125-017-9392-y