Recent study at Ontario Veterinary College: Assessing Temperament in Young Puppies By: Pamela J. Reid & Nathan J. Penny Discord between owner and dog is often the result of a fundamental mismatch between the lifestyle of the human and the behavioural tendencies of the dog. Attempts to avoid mismatches have led to the development of puppy tests, purported to assess the basic personality of the puppy, and predict how it will behave as an adult. The goal of our study was to standardize the popular Puppy Aptitude Test and correlate the results with both breeder assessments of the puppies, as well as with owner reports of the puppies' behaviour during the first year following adoption. We ran 46 litters (279 puppies in total), each at 49 days of age, through a battery of tests designed to assess their sociability to humans and their reactivity to stimuli. The results correlated moderately well with the breeder assessments but did not predict how the puppies would behave in their permanent homes. We conclude that a standardized test is able to generate an accurate picture of puppy temperament, but the changing milieu during development and the influence of learning prevent the reliable prediction of future behaviour.