Prepositions name spatial relationships. But they are also used to convey abstract, non-spatial relationships —raising the question of how the abstract uses relate to the concrete spatial uses. Despite considerable success in delineating these relationships, no general account exists for the two most frequently extended prepositions: in and on. We test the proposal that what is preserved in abstract uses of these prepositions is the relative degree of control between the located object and the reference object. Across four experiments, we (...) find a continuum of greater figure control for on and greater ground control for in. These findings bear on accounts of semantic structure and language change, as well as on second language instruction. (shrink)