The socialisation and habituation period for a puppy is between 6 -16 weeks. This is the time when your puppy is much less fearful and much more likely to approach and investigate novel things. At this time it is very important that your puppy is heavily socialised with other animals and people, remembering to include dogs and people of all shapes, sizes and gaits. This must be good experience for your puppy. After the socialisation period ends, your puppy will behave to increase distance, through the mechanisms of flight or fight, from anything that he has not been socialised with. Living in London there are lots of horses and swans and scary red buses.