Abstract
Recent debates on mental extension and distributed cognition have taught us that environmental resources play an important and often indispensable role in supporting cognitive capacities. In order to clarify how interactions between the mind –particularly memory– and the world take place, this paper presents the “selection problem” and the “endorsement problem” as structural problems arising from such interactions in cases of mental scaffolding. On the one hand, the selection problem arises each time an agent is confronted with a cognitive problem, since she has to choose whether to solve it internally or externally. How does she choose? On the other hand, when confronted with the internally or externally retrieved solution to a cognitive task, the subject has to decide whether to endorse the information. How does the subject decide whether to endorse it or not? The last section proposes a solution to each problem in terms of metamemory and metacognitive feelings. Metamemory evaluates memory each time the subject is confronted with a memory task and elicits either a positive or negative metacognitive feeling that guides the decision