Randomized Experiment

PNAS 123/35 pp. e2530627123-e2530627123 2026-08-28 Original Personality pairing improves human–AI collaboration Harang Ju, Sinan Aral Abstract Here we examine how AI agent "personalities" interact with human personalities to shape human-AI collaboration and performance. In a large-scale, preregistered randomized experiment, we paired 1,258 participants with AI agents prompted to exhibit varying levels of the Big Five personality traits. These human-AI teams produced 7,266 display ads for a real think tank, which we evaluated using 1,168 independent human raters, and a field experiment on X that generated nearly 5 million impressions. We found that human and AI personalities individually shaped ad quality and teamwork and that human-AI personality pairings directly influenced ad quality. For example, extraverted humans paired with conscientious AI produced the lowest quality ads, followed by conscientious humans paired with agreeable AI and neurotic humans paired with conscientious AI. In the field experiment, ad quality significantly influenced ad performance, measured by click-through rates and cost-per-click. Together, these results demonstrate that personality pairing can improve human-AI collaboration and performance. They also motivate future research on the complex implications of AI personalization for human-AI collaboration, teamwork, and performance.

PMR — pp. 1-38 2026-06-01 Original The impact of timebanking on volunteering behaviors Khaldoun AbouAssi, Rui Wang, Ge Xin Abstract Global declines in formal volunteering have prompted interest in alternative mechanisms like timebanking. This study investigates the impact of timebanking on future volunteering intentions using a between-subjects randomized survey experiment (n= 361) in Shanghai, China. Participants exposed to a timebanking vignette were nearly three times more likely to express high-frequency volunteering intentions than the control group. This positive effect was most pronounced among frequent volunteers with strong intrinsic satisfaction, but attenuated among self-interested respondents. These findings suggest that institutionalized, non-monetary incentives can increase willingness to participate without undermining intrinsic motivation.