One benefit of working in groups is that group members can learn from each other how to perform the task, a phenomenon called group-to-individual transfer (G-I transfer). In the context of quantitative judgments, G-I transfer means that group members improve their individual accuracy as a consequence of exchanging task-relevant information. This improved individual accuracy allows groups to outperform the average of a comparable number of individuals, that is, G-I transfer leads to synergy. While there is mounting evidence that group members benefit from G-I transfer in quantitative judgment tasks, we still know rather little about what exactly group members learn from each other during this transfer. Here, we build on the distinction between metric knowledge (knowing what constitutes a plausible range of values) and mapping knowledge (knowing the relative magnitude of the targets) to gain further insights into the nature of G-I transfer. Whereas previous research found evidence that G-I transfer improves group members' metric knowledge, there is, so far, no evidence that group discussion also improves mapping knowledge. Using a multicue judgment task, we tested whether group members would benefit from G-I-transfer and, if so, whether this G-I transfer would manifest in the form of improved mapping knowledge. The results of two experiments suggest that this is the case. Participants who worked in real interacting groups outperformed participants who worked individually, and this increase in accuracy was accompanied not only by improved metric but also by increased mapping knowledge.