Marion K. Underwood is an American psychologist and dean of Purdue University's College of Health and Human Sciences, a position she assumed on August 1, 2018. She is a leading researcher in social aggression and is a fellow of the Association for Psychological Science.
Underwood graduated from Wellesley College in 1986 and received her Ph.D. in clinical psychology from Duke University in 1991. She joined the faculty at Reed College in 1991, where she received tenure. From 1998 to 2018, she had various roles at the University of Texas at Dallas. In 2008, she was named to an Endowed Chair, as Ashbel Smith Professor. From 2015 to 2018, she served as dean of graduate studies and associate provost.
Her research has been funded by the National Institutes of Health since 1995. She studies social aggression (also known as relational aggression) in children and teens as well as adolescents’ use of social media, text messaging, and other digital forms of communication. Her work has been seen on CNN, The New York Times, and The Atlantic, among others.
As part of a longitudinal study, Underwood provided free BlackBerrys to ninth-graders in exchange for permission to study the teens' text messages. On average, students sent 1,321 text messages per month (about 43 per day). Underwood and her colleagues found that less than 2% of text messages had antisocial content (such as rule-breaking, drug use, physical aggression, or property crimes.)  Many of the text messages included teens "building each other up" and providing support.
- Underwood, Marion K.; Ehrenreich, Samuel E.; More, David; Solis, Jerome S.; Brinkley, Dawn Y. (2015). "The BlackBerry Project: The Hidden World of Adolescents' Text Messaging and Relations With Internalizing Symptoms". Journal of Research on Adolescence. 25 (1): 101–117. doi:10.1111/jora.12101.
- Underwood, Marion K.; Ehrenreich, Samuel E. (2017). "The Power and the Pain of Adolescents' Digital Communication: Cyber Victimization and the Perils of Lurking". American Psychologist. 72 (2): 144–158. doi:10.1037/a0040429.
- Brinkley, Dawn Y.; Ackerman, Robert A.; Ehrenreich, Samuel; Underwood, Marion K. (2017). "Sending and Receiving Text Messages with Sexual Content: Relations with Early Sexual Activity and Borderline Personality Features in Late Adolescence". Computers in Human Behavior. 70: 119–130. doi:10.1016/j.chb.2016.12.082.
- Underwood, Marion K. (April 10, 2003). Social Aggression among Girls (The Guilford Series on Social and Emotional Development). The Guilford Press. ISBN 978-1572308657.
- Underwood, Marion K.; Rosen, Lisa H., eds. (September 19, 2013). Social Development: Relationships in Infancy, Childhood, and Adolescence. The Guilford Press. ISBN 978-1572308657.
- Huckaby, M. (April 20, 2018). UT Dallas dean to take helm of Purdue’s Health and Human Sciences. Purdue University press release, https://www.purdue.edu/newsroom/releases/2018/Q2/ut-dallas-dean-to-take-helm-of-purdues-health-and-human-sciences.html, retrieved November 20, 2018.
- Staff writer (April 23, 2018). Purdue names health and human sciences dean. Inside INdiana Business. Retrieved from http://www.insideindianabusiness.com/story/38019820/purdue-names-health-and-human-sciences-dean-marion-underwood-christine-ladisch November 20, 2018.
- Piper, J. (May 31, 2018). Transitions: Missouri State campus selects its first female chancellor, U. of Southern California resigns. The Chronicle of Higher Education. Retrieved from https://www.chronicle.com/article/Transitions-Missouri-State/243543 on November 20, 2018.
- CNN Press Room (September 10, 2015). CNN’s Anderson Cooper 360° breaks news about teens and social media in provocative two-year long investigation. Retrieved from http://cnnpressroom.blogs.cnn.com/2015/09/10/cnns-anderson-cooper-360-breaks-news-about-teens-and-social-media-in-provocative-two-year-long-investigation/ on November 20, 2018
- Marion K. Underwood CV (November 2017), retrieved from https://utdallas.edu/bbs/files/marion-underwood-cv.pdf on November 20, 2018.
- Endowed Chairs & Professorships, UT Dallas. Retrieved from https://utdallas.edu/chairs/profiles/dr-marion-underwood/ on November 20, 2018.
- Society for Research in Child Development (2019). Lunch with the Leaders Biographies. 2019 Biennial Meeting Program. Retrieved from https://www.srcd.org/meetings/biennial-meeting/lunch-leaders/2019-lunch-leaders-biographies on December 13, 2018.
- Dell'Atonia, K. (October 5, 2015). Seven ways parents can help 13-year-olds start their social media lives right. The New York Times. Retrieved from https://parenting.blogs.nytimes.com/2015/10/05/seven-ways-parents-can-help-13-year-olds-start-their-social-media-lives-right/ on December 13, 2018.
- Senior, J. (August 4, 2018). The high school we can’t log off from. The New York Times, Opinion. Retrieved from https://www.nytimes.com/2018/08/04/opinion/sunday/the-high-school-we-cant-log-off-from.html on December 13, 2018.
- Roberts, K. (February 26, 2014). The psychology of begging to be followed on Twitter. The Atlantic. Retrieved from https://www.theatlantic.com/health/archive/2014/02/the-psychology-of-begging-to-be-followed-on-twitter/283947/ on December 13, 2018.
- ScienceDaily (September 9, 2013). Antisocial texting by teens linked to bad behavior. Retrieved from https://www.sciencedaily.com/releases/2013/09/130909172232.htm on December 13, 2018.
- Bristol, T. (August 2, 2011). Texting changes the way kids communicate. Journal Review. Retrieved from http://www.journalreview.com/news/article_0a94c57a-bca5-11e0-97f3-001cc4c002e0.html on December 13, 2018.