Mary MacLennan

Mary MacLennan is the Senior Advisor on Behavioural Science to the Executive Office of the UN Secretary-General, where she leads efforts to integrate behavioural science across the UN. A behavioural scientist with over 10 years of experience, she also leads the UN Behavioural Science Team and the UN Behavioural Science Group within the UN Innovation Network, supporting 70+ UN entities across 150+ countries through a global network of 8,000+ colleagues.

Her work sits at the intersection of behavioural science and AI and focuses on adoption and evaluation as systems move into real-world decision environments. She is particularly interested in grounding model behaviour in real-world behavioural evidence, synthetic data and simulations for realistic testing, and the economic and institutional implications of AI deployment across diverse contexts. She is also affiliated with the University of Cambridge and the London School of Economics.