Choice-based severity scale (CSS): assessing the relative severity of procedures from a laboratory animal’s perspective 1Welfare and Cognition Group, Cognitive Neuroscience Lab, German Primate Center, Goettingen, Lower Saxony, Germany 2Population and Behavioral Health Services, California National Primate Research Center, University of California, Davis, California, United States 3Leibniz-ScienceCampus Primate Cognition, Goettingen, Lower Saxony, Germany 4Faculty for Biology and Psychology,...