One day, you have a star pupil: a four-month-old puppy who sits on command, follows your every move, and has a recall that would make a sheepdog jealous. Then, seemingly overnight, that same dog looks at you when called, tilts their head as if you’re speaking an ancient, forgotten language, and decides that a discarded candy wrapper across the street is infinitely more interesting than your high-value liver treats.

Welcome to canine adolescence.

Occurring roughly between 6 and 18 months (depending on the breed), this phase is the “Great Testing.” It is the primary reason dogs are surrendered to shelters. But before you conclude that your dog has “gone bad” or that you’ve failed as a trainer, it’s time to look under the hood. Your dog isn’t being spiteful; their brain is quite literally under construction.

The “Teenage” Brain: Biological Rewiring

During adolescence, a dog’s brain undergoes a massive overhaul …