How do people tackle indeterminate spatial descriptions, that is those descriptions for which several representations are possible? Take for instance the two following statements: B is to the left of A, C is to the left of A. This description is indeterminate because it is compatible with at least two possibilities: (1) C B A; (2) B C A. Studies on human reasoning have shown that people tend to reduce the complexity of such indeterminate descriptions by representing only one possibility. Which one do people favour? Is one possibility easier to work out than the other? Is one possibility more plausible than the other? Two competing hypotheses make different predictions about the representation people favour. If the building of the representation is driven by what we call manipulation difficulty, then (1) is more likely to be constructed than (2) because (2) results from reorganising the representation following the first statement where B is adjacent to A (i.e. B A) while (1) is just an extension of this initial representation. However, if the representation process is driven by pragmatic factors, then (2) is more likely to be built than (1) because the second statement could be interpreted as implicating "C is not to the left of B". Indeed, if C had been to the left of B it would have been more appropriate to utter, "C is to the left of B" rather than "C is to the left of A". Data from several experiments show that both manipulation difficulty and pragmatic factors play a role in determining participants' representations.