Proceedings of the Annual Meeting of the Cognitive Science Society

System delays affect user performance and experience when interacting with computers. We investigated the effectsof different prediction relations between delay duration and response requirements on user performance. In one experiment,delay duration predicted, to different degrees (50 % vs. 75 % vs. 100 %), the following system response. Predictabilitysubstantially increased users’ response speed, while adaptation was highly flexible, between different prediction regimes. Ina second experiment, users’ responses predicted system delay duration. Compared to the first experiment, users’ responsespeed was moderately increased, while the adaptation was rather inflexible across different prediction regimes. In a thirdexperiment, we directly compared both types of predictability. The results confirmed a stronger and more flexible adaptationeffect when time predicted the system response, compared to when users’ responses predicted time. These findings haveimportant implications for scheduling data transmission rates across different users in internet-based parallel computing.