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School of Arts and Sciences

Graduate School Leadership

Robert CookRobert Cook
Dean of the Graduate School of Arts and Sciences
Dean of Academic Affairs for Arts and Sciences
Professor of Psychology

Dean Cook supports graduate programs at all levels and serves as the liaison between students, faculty, and administration on all aspects of graduate education within the school. This includes strengthening the quality and diversity of the graduate student body and integrating career and professional development training into our student education. 

Dean Cook began his career at Tufts in 1986 as an assistant professor in the Department of Psychology. He was promoted to full professor in 1999, and served as department chair from 2005 to 2011. He has studied animal cognition and behavior for more than 25 years. His comparative research, supported by the National Science Foundation and the National Institutes of Health, has focused on stimulus control, discrimination learning, and memory in animals. In particular, he is interested in the mechanisms of visual perception and discrimination learning in pigeons and starlings, and their comparative relations to our own perception of the world.

Dean Cook received a BS in psychology from Ohio State University and his doctorate in biopsychology from the University of California, Berkeley. He is co-founder and current publisher of Comparative Cognition & Behavior Reviews and has served on the editorial boards of the top journals in animal cognition. He is a member of the American Psychological Association and a past president of the Comparative Cognition Society.


Sarah HerchelSarah Herchel
Associate Dean of the Graduate School of Arts and Sciences

Affiliate Faculty, Department of Education

Associate Dean Sarah Herchel works to foster excellence, inclusion, and innovation at the Graduate School of Arts and Sciences. As a member of the strategic leadership team, she partners with faculty to create training and development opportunities, identifies areas for new academic programs, and is the liaison for the School’s accreditation efforts.   

Associate Dean Herchel has a deep knowledge of higher education administration, and of graduate education in particular. Prior to arriving at Tufts in 2013, she held positions at Boston University’s Questrom School of Business and at Babson College’s F.W. Olin Graduate School of Business. She has an MA in English from Lehigh University, an EdM from Boston University, and a PhD in Educational Studies from Lesley University. Her areas of research interest include adult learning, assessment, and higher education administration.


Jacqueline DejeanJacqueline (Jackie) Dejean
Assistant Dean, Diversity & Inclusion, Graduate School of Arts and Sciences
Assistant Dean of Research for Arts and Sciences

Jackie Dejean assumed the role of assistant dean of diversity and inclusion for GSAS in 2019, and is and focused on advancing the strategic plan for diversity, equity and inclusion for the School. In addition, she has served as assistant dean of research for Arts and Sciences since 2017 where she is tasked with advancing the strategic research agenda of the School of Arts and Sciences including program development to achieve strategic goals. She has been launching new programs furthering that mission, most notable of which is the VERSE Program.

Previously, she held positions as director of research affairs and medical college associate vice president of grants and research. She has spent over 20 years in the field of research administration at teaching, research, and medical institutions. She has a long history of civic engagement around diversity and inclusion. She completed her doctorate in law and policy (DLP) at Northeastern University. She holds an AB from Brown University and a Master’s in organizational psychology from William James College (formerly the Massachusetts School of Professional Psychology).