Description:
Over the last three decades, an increased focus on engaging K-12 students in historical thinking has highlighted the importance of providing students with direct instruction regarding how causal relationships are formed in text. Many teachers provide this instruction by focusing on explicit causal structures, neglecting implicit forms of causation such as causal asyndetic constructions. Studies of United States history textbooks have found instances of causal asyndetic construction use, similar to the implicit constructions found in studies of spoken and written discourse. This study examines two questions: (1) Do causal asyndetic constructions occur in history textbooks with similar frequency to causal conjunctions and causal material processes? and (2) How is causal asyndetic cohesion signaled in history texts? A mixed methods analysis of two middle school and two high school textbooks demonstrates that causal asyndetic constructions are used as frequently, if not more frequently, than explicit means of expressing causation; they are signaled through authors' uses of modals, mental processes, relational processes, and verbal processes. The use of mental processes to signal causal asyndetic constructions far outnumbered other implicit signals, accounting for 58% of the total. These findings suggest that teachers need to provide students with instruction about how to identify and make meaning of causal asyndetic constructions as well as causal conjunctions and explicit processes.