Abstract
The debate on when and how machines can be creative is gaining momentum, yet little is known about the implications of different interfaces on creative writing. To address this gap, we present a case study involving six novelists who had recently completed an advanced literary course on fictional characters and had no or minimal experience with automated text generation. The participants were instructed to craft a fictional character of their choice using a commercial platform. We observed user behaviour in two half-day workshops, facilitated group discussion, studied the logs, and conducted individual interviews. Results highlighted a multilayered stage for fictional and artificial characters. It has to accommodate multiple roles and interaction strategies, alongside communication breakdowns. The user played the role of the author who prompted an automatic ghostwriter. Alternatively, they impersonated a fictional character who roleplayed with the artificial one. Prompting was constrained by the principles of simplicity and logic. Roleplaying was driven by suspension of disbelief and surprise. Communication breakdowns emerged due to a lack of common ground and a profound mismatch between the system functionality and the user requirements. Overall, the interaction proved potential in the ideation of flat, side characters, but was considered unsuitable for round protagonists. We conclude with a call to the HCI community to take the design of natural language interfaces seriously and suggest the metaphor of improvisational theatre to inspire future studies.