The aim of this paper is to compare the effects of different communication media on the quality of arguments and the development of argumentative reasoning. The study involved 73 undergraduate students. It consisted of a pre-test, an intervention session consisting of either an asynchronous online discussion or a face-to-face discussion, and a post-test. The pre-test consisted of a mini essay to ascertain participants' opinion of smacking, and a 21-point smacking scale, where participants indicated how much they agreed or disagreed with smacking. The online group participated in a seminar discussion over a period of 2 weeks. The face-to-face group participated in the seminar discussion for a 1-h period. The seminar discussion was about the detrimental effects of smacking on children's development. One week after the seminar discussion, the post-test was administered. No statistically significant differences were found between the two conditions in terms of improvement in the quality of the students' arguments. However, the quality of the argumentation used in face-to-face was higher than that used in the online discussions. The implications of these findings for theoretical models of collaborative activity are discussed.