Compared to traditional pen-and-paper presentation of information, computer-assisted argument mapping seems to be more efficient in developing lower order thinking skills such as memory and comprehension. The present study investigated the impact of argument map construction and reading via computer versus pen and paper on English as a foreign language (EFL) majors’ comprehension, recall, and retention of argumentative texts. To this end, 120 Iranian EFL undergraduates were divided into low and high proficiency levels after taking a language proficiency test. Next, they were randomly assigned to two experimental groups; each group received 12 sessions of argument mapping instruction, one via computer and the other via pen and paper. At the end of the term, participants randomly received two argument map sizes (small vs. large) and were given 15 minutes to read the maps. Then tests of recall and comprehension relevant to the maps were administered, followed by a test of retention within a two-week interval. The results revealed that after controlling for spatial and verbal covariates, the type of treatment had a significant effect on recall, retention, and comprehension, with the software group outperforming the pen-and-paper group; however, proficiency level and argument size did not show any significant effect.