National University of La Plata 1 article published in JoVE Behavior Assessment of Mouse Judgment Bias through an Olfactory Digging Task Aileen MacLellan*1, Agustina Resasco*2,3, Lauren Young4, Georgia Mason1 1Department of Integrative Biology, University of Guelph, 2Institute of Cell Biology and Neurosciences, National Scientific and Technical Research Council-University of Buenos Aires, 3Laboratory of Experimental Animals, Faculty of Veterinary Sciences, National University of La Plata, 4Department of Animal Biosciences, University of Guelph This article provides a detailed description of a novel mouse judgment bias protocol. Evidence of this olfactory digging task's sensitivity to affective state is also demonstrated and its utility across diverse research fields is discussed.