  We investigate how multiple sliders with and without feedforward
visualizations influence users' control of generative models. In an online
study (N=138), we collected a dataset of people interacting with a generative
adversarial network (StyleGAN2) in an image reconstruction task. We found that
more control dimensions (sliders) significantly increase task difficulty and
user actions. Visual feedforward partly mitigates this by enabling more
goal-directed interaction. However, we found no evidence of faster or more
accurate task performance. This indicates a tradeoff between feedforward detail
and implied cognitive costs, such as attention. Moreover, we found that
visualizations alone are not always sufficient for users to understand
individual control dimensions. Our study quantifies fundamental UI design
factors and resulting interaction behavior in this context, revealing
opportunities for improvement in the UI design for interactive applications of
generative models. We close by discussing design directions and further
aspects.
