You can usually get a snapshot of a puppy's temperament by the time they are 7 weeks of age. By 7 weeks old, your puppy's personality traits will become more obvious. When with the rest of their litter, you may notice your puppy being bolder, or, in contrast, allowing other puppies to push them around. Puppies in their seventh week are in their secondary socialization period, too, wherein they become more confident with approaching strangers. It's important that your pup gets plenty of exposure to people you trust during this period so that they can continue to develop healthy social skills. Puppies at this age will also be very interested in play fighting with their littermates, which is important for their mental and physical development.