Sexual selection theory predicts that additional resources will have a greater impact on males' compared with females' reproductive success. Consequently, we expected that strong cues signalling increased resource availability should augment cognitive functioning associated with long-term maximization of reproductive outcomes (inhibition, working memory) in human males. In human females, who can rely on assistance in resource-rich environments, we expected the opposite effect. We tested this prediction in lower socio-economic status children, since their poverty increased the relative salience of the cues available in a limited experimental situation. We show that cues indicative of food availability increased impoverished young males' inhibitory and working memory capacities compared with males who viewed photographs of food. By contrast, cues indicating food availability exerted the opposite effect on females. These results indicate that cues related to resource availability have differential effects on basic cognitive functions associated with strategic behaviour in males and females. The findings also demonstrate remarkable plasticity in fundamental cognitive processes in young children, even those from impoverished backgrounds.