  Automated story plot generation is the task of generating a coherent sequence
of plot events. Causal relations between plot events are believed to increase
the perception of story and plot coherence. In this work, we introduce the
concept of soft causal relations as causal relations inferred from commonsense
reasoning. We demonstrate C2PO, an approach to narrative generation that
operationalizes this concept through Causal, Commonsense Plot Ordering. Using
human-participant protocols, we evaluate our system against baseline systems
with different commonsense reasoning reasoning and inductive biases to
determine the role of soft causal relations in perceived story quality. Through
these studies we also probe the interplay of how changes in commonsense norms
across storytelling genres affect perceptions of story quality.
