I often have people ask me if dogs should be allowed off-leash in areas where they are safe from harm. And, often tagged on to this question is a query about whether on-leash dogs are more assertive or aggressive than off-leash dogs. I wish I knew. Despite a great deal of interest in this question there are no formal studies to the best of my knowledge. However, the answers that come my way overwhelmingly claim that off-leash dogs are, indeed, less assertive or aggressive than on-leash dogs (some interesting discussions can be found here).

Read more: https://www.psychologytoday.com/blog/animal-emotions/201605/why-dogs-belong-leash-its-win-win-all