This study (Q21) is one of a series of studies performed in the Szechtman lab at McMaster University and deposited in the FRDR public repository as a collection under the name "A Digital Library of Behavioural Performance in Standardized Conditions - Szechtman Lab Collection". This collection as a whole constitutes a big dataset containing raw data objects of video, track, and path plot records of rats exploring for 55 minutes a large testing environment in a standardized paradigm during chronic treatment with psychostimulant drugs; for details of this big dataset see, https://www.frdr-dfdr.ca/repo/collection/szechtmanlab. The historical context for study Q21 was Project_08 entitled: "Probing the parameters of sensitization and compulsive checking". Title of experiment in Q21 was "Development and temporal organization of compulsive checking induced by repeated injections of QNP (0.5 mg/kg)". This experiment was embedded in a larger study, Project_09 entitled: "Probing the environmental modulation of sensitization and compulsive checking", where the title of the experiment was "Effect of separating pups from maternal nest for 15 or 180 min on postnatal days 2 to 15 on the development of compulsive checking induced by repeated injections of quinpirole in adult male rats".