Dr O’Brien received her undergraduate training in psychology at the University of Cape Town, South Africa. She was awarded two Gates scholarships to complete her MPhil and PhD respectively, in Social and Developmental Psychology at the University of Cambridge. She was then a research associate in the then Faculty of Social and Political Science, University of Cambridge. Dr O’Brien has supervised on psychology papers for numerous Cambridge Colleges. She was Director of Studies in SPS/PPS/HSPS at Peterhouse from 2007-2017 and has directed studies in PBS at Magdalene College since 2014, at Jesus College (Part I) since 2020, and at Wolfson College since 2022. She is a Bye-Fellow in PBS at Lucy Cavendish College, Jesus College and Wolfson College. In 2018, she was short-listed for a CUSU student-led Teaching Award as supervisor, one of only 10 such supervisors selected in the School of Social Sciences.