This matlab-based script implements a version of the modified Iowa Gambling Task (IGT) as described in: Cauffman, E., Shulman, E.P, Steinberg, L., Claus, E., Marie T. Banich, M.T., Sandra Graham, S., & Jennifer Woolard, J. (2010). Age Differences in Affective Decision Making as Indexed by Performance on the Iowa Gambling Task. Developmental Psychology, Vol. 46, No. 1, 193-207.