Aiko trained in experimental psychology at Keio University and then at Carnegie Mellon, where her doctoral work on the relationship between deliberation and confidence overturned several comfortable assumptions about reflective thinking. She has been at the Institute since 2013 and leads the Reflection Paradox project, which studies conditions under which slowing down makes people more certain but no more accurate. She also co-leads the 14-country Risk Across Cultures study, one of the largest comparative decision-science projects currently running.