Investigating putative depression-like states in the domestic dog: does greater time spent displaying waking inactivity in the home kennel co-vary with negative judgment of ambiguity?

•This study aimed to test whether greater time spent displaying waking inactivity could reflect a depression-like condition in domestic dogs.•We tested whether shelter dogs that spent more time ‘awake but motionless’ in the home-pen would also show negative judgment of ambiguity.•Stray dogs completed training for the judgement bias task quicker than dogs from other origins, but all dogs exhibited highly positive judgements.•As such, there were no associations between time spent ‘awake but motionless’ and the dogs’ judgement of ambiguity.•We discuss why such ‘optimism’ may have been (e.g. sensitivity to access stimulation, probe test trial numbers) & further research directions.