A study has found that dog personalities are strongly linked to those of their owners. Researchers asked pet parents to rate themselves on personality dimensions, such as neuroticism and extraversion, and corresponding traits in their dogs. The study also found that like humans, dogs' personalities change over time, with older dogs being harder to train. Dogs and owners were also found to share certain personality traits. Exposure to obedience classes was associated with more positive personality traits across a dog's lifespan, highlighting the power of human influence on a dog's personality. Future research will examine how the environment affects dog behavior.