How do new ideas come to be adopted during discourse?
Here, we present comparative case studies of two young adolescents engaged in electronic dialogs on a social issue with a sequence of partners. We trace how an individual coordinates existing ideas with new input the interaction provides. Tracing the evolution of an individual’s ideas entails close examination of the process by means of which it occurs. The skills the individual brings to the interaction shape this evolution, as well as undergo development themselves as a consequence of practice. The two case studies revealed strikingly different patterns, and their comparison provides insights into the processes involved. Their description encompasses not simply the knowledge but also the argument skills the individual brings to the activity and, underlying them, understandings of the purposes and objectives of argumentation. Metacognitive talk about their thinking may be key in conferring the benefit the dialogic activity provides; it aides in dissociating a belief from the holder of the belief, thereby promoting claims being situated in argumentative relation to one another. Text-only communication proved a beneficial condition for this to occur.