Response-effect compatibility of finger-numeral configurations in arithmetical context.

The present study aimed at testing, by means of a response-effect compatibility paradigm, whether finger-numeral representations derived from finger counting may underlie simple arithmetic problem solving in adults. Participants were asked to provide a verbal response to simple additions, which triggered the presentation of the correct (Experiment 1) or an incorrect (Experiment 2) response, displayed either as a configuration of fingers or as a series of rods. Answers were faster with finger configurations than with rods, and only when the finger configuration showed the correct result. These findings support the idea that, even in adults, simple arithmetic operations are still unconsciously underlain by finger-numeral representations.