An important developmental task is learning to organize experience by forming conceptual relations among entities. (For example, a "lion" and a "snake" can be linked because both are animals; a lion and a cage can be linked because the "lion" lives in the "cage".) We propose that representational medium (i.e., pictures vs. objects) plays an important role in influencing which relations children consider. Prior work has demonstrated that pictures more readily evoke broader categories, whereas objects more readily call attention to specific individuals. We therefore predicted that pictures would encourage taxonomic and shared-property relations, whereas objects would encourage thematic and slot-filler relations. We observed 32 mother-child dyads (M child ages = 2.9 and 4.3) playing with pictures and objects, and identified utterances in which they made taxonomic, thematic, shared-property, or slot-filler links between items. The results confirmed our predictions and thus support representational medium as an important factor that influences the conceptual relations expressed during dyadic conversations. (Contains 4 tables and 1 figure.)