Petitto received her Bachelor of Science degree in Psychology with Highest Honors in 1975 from Ramapo College (New Jersey, USA) while taking undergraduate classes and conducting cross-species language research with the chimpanzee  “Nim Chimpsky” (named after Noam Chomsky) at Columbia University, New York — on-site 1973-1976 and with scholarly collaborations continuing 1976-1979.

Petitto played a leading role on Project Nim Chimpsky as the chimp’s “Primary/Head Sign Language Teacher” and “Surrogate Mother,”  as well as the project’s “Project Coordinator.” Despite the dangers of living with a chimpanzee, Petitto lived with and cared for Nim as a child in an attempt to create a natural language, cognitive, and highly caring and rich social environment, mirroring that of a human child. Most all of the chimp’s scientific training and accomplishments were achieved during her tenure on the Project.

Petitto then conducted psycholinguistic research on American Sign Language (ASL) in the Neurolinguistics Laboratory of Dr. Ursula Bellugi at The Salk Institute for Biological Studies (La Jolla, CA), along with Linguist, Dr. Edward Klima, of the University of California, San Diego, where Petitto began graduate study in the Department of Linguistics (1976-1977).

Petitto continued graduate study at New York University (Masters degree, 1978), where she conducted psycholinguistic research on the processing demands of signing and speaking at the same time (“Simultaneous Communication”) with Dr. Gloria Marmor. She then undertook psycholinguistic research on the phonological structure of American Sign Language with Dr. William Stokoe in “The Linguistic Research Laboratory” at Gallaudet University (Washington, D.C., 1978-1979). In fall 1979, Petitto began graduate study at Harvard University (Cambridge, MA) in the Harvard Graduate School of Education’s Department of Human Development and Psychology (Language and Cognition Track), where she received her Masters degree (1981; advisors, Drs. Roger Brown, Courtney Cazden, Jerome Kagan, Sheldon White, Ursula Bellugi, and Noam Chomsky, Linguistics, M.I.T.) and Doctoral degree (1984; advisors, Drs. Roger Brown, Courtney Cazden, Sheldon White, and Ursula Bellugi).

In fall, 1983, Petitto was appointed Assistant Professor in the Department of Psychology at McGill University (Montreal, QC) and, in the same year, won a coveted John D. and Catherine T. MacArthur Foundation Postdoctoral Award to study with Dr. Ursula Bellugi and Dr. Elizabeth Bates. Petitto built a vibrant laboratory in Cognitive Neuroscience at McGill University (1983-2001), while conducting Positron Emission Tomography (PET) brain-imaging studies as a Research Scientist at the Montreal Neurological Institute working with Drs. Robert Zatorre, Brenda Milner, and others.

Petitto is presently the Science Director and Co-Principal Investigator at the National Science Foundation and Gallaudet University’s Science of Learning Center, called “Visual Language and Visual Learning, VL2” in Washington, D.C. Petitto is also Professor of Psychology and Senior Scientist of her own brain-imaging laboratory, called “Brain and Language Lab for Neuroimaging, BL2” at Gallaudet University and an Affiliated Professor in the Department of Psychology at Georgetown University. Before this, Petitto was at the University of Toronto (2007-2011), and, prior, Petitto was a Research Professor of Psychology, as well as Chair of a department that Petitto newly designed/created and helped to establish, called the “Department of Educational Neuroscience and Human Development,” at Dartmouth College (Hanover, NH, 2001-2007).