Group Dynamic Assessment (G-DA), introduced by Poehner (2009), applies mediation through concurrent and cumulative approaches. This study investigated the effect of the two approaches on Iranian homogeneous and heterogeneous EFL learners' auditory memory in listening tasks. Eighty female intermediate EFL learners were chosen as the participants of the study. They were assigned to two groups of forty homogeneous and forty heterogeneous learners. Then, each group was divided into two experimental groups with twenty participants in each. Homogeneous and heterogeneous participants were assessed through both concurrent and cumulative approaches. To find out the main and interaction effect of concurrent and cumulative G-DA and homogeneity and heterogeneity of EFL learners, the post-test scores of the participants were analysed through a two-way ANOVA. The results indicated that G-DA approaches on the one hand and homogeneity and heterogeneity of EFL learners on the other, had both significant main and interaction effect on EFL learners' auditory memory. For the independent effect of both approaches, a one-way ANOVA was also used. The results indicated that cumulative G-DA had more significant effect than concurrent one on heterogeneous EFL learners' auditory memory. ANOVA analysis also proved that the two approaches did not differ in their effect on homogenous learners.
