Carrasco, M. & Seamon, J.G. (1996). Priing impossible figures in the object decision test: The critical importance of perceived stimulus complexity. Psychonomic Bulletin & Review, 3(3): 344-351.

Abstract
Previous research showed that object decision priming was found for possible, but not impossible, three-dimensional objects (e.g., Schacter, Cooper, & Delaney, 1990; Schacter, Cooper, delaney, Peterson, & Tharan, 1991). We tested those objects and found that the impossible objects were subjectively more complex than the possbible objects. We then constructed two sets of possible and impossible objects- one set that was equated for complexity, and one set that differed- for use in the object decision test. The results showed that when impossible objects were high in complexity and possible objects were low in complexity; priming was found only for possible objects; when possible and impossible objects were equated at a moderate level of complexity, priming was observed for both object types. These findings indicate that perceived object complexity, more than object possibility-impossibility, determined priming in the object decision test. The demonstration of object decision priming for possible objects calls for a reformulation of the structural description system explanation.