Decoupling of Usefulness and Novelty: Evaluating the Impact of Generative AI on Design Outputs and Novice Designers' Creative Thinking

People are increasingly leveraging generative AI (GenAI) for design tasks, making it critical to understand GenAI’s impact on design outcomes and users’ creative capabilities. We conducted a within-subjects experiment where 36 participants designed advertisements both with and without GenAI. Evaluations from clients and online volunteers revealed that GenAI-supported designs were perceived as significantly more creative and unconventional. Additionally, online volunteers, but not clients, rated these designs as more visually appealing. However, neither group perceived differences in usefulness, and clients noted no improvement in brand alignment, highlighting a notable decoupling of novelty and usefulness (two established components of creativity) in GenAI-supported design outputs. Although short-term GenAI use did not broadly influence participants’ creative thinking or experience, subgroup analyses indicated increases in divergent thinking among participants new to GenAI relative to participants with GenAI experience. We discuss the implications of the decoupling effect and GenAI’s influence on humans’ creativity.