Mean percentages correct for the three experimental conditions: finite verbs in base-generated position (V-in-V; 10 items), auxiliaries in base-generated position (Aux-in-I; 10 items), total base-generated position (no movement; this is V-in-V + Aux-in-I; 20 items), and moved auxiliaries (Aux-in-C: +movement; 20 items)