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third crytical stage 29-49 days, 4-7wks. fourth stage 50-84days, 7-12wks

At this age puppies will venture away from the nest – although not very far- and so do a little exploring. At the beginning of a puppy’s sixth week, the awareness of society will dawn, that is, the society of man and the society of dog.A puppy’s nervous system and his trainability are developing and by the end of the third critical period will have developed to capacity. Unfortunately some dog books say that a puppy has the brain of an adult at the conclusion of third critical period. This is not true and research proves it. Therefore a more comprehensive look at what takes place during this third critical period is certainly in order.

During this period a puppy will learn to respond to voices and will begin to recognise people. A social ‘pecking order’ will be established among the puppies in the litter. Some of the puppies will learn to fight for their food and will learn to be bullies. The litter mates that are cowed by aggressive tendencies of the others will become shy.

The scientific tests at Hamilton Station have shown that it is advantageous for a puppy to remain with the litter long enough to acquire a little competitive spirit but that too much is detrimental to the puppy’s emotional growth. The pups that remain in the litter after the seventh week will begin to develop bullyish or cowed tendencies – which will remain with them into adulthood. The longer a puppy remains with the litter after completing the seventh week of its life, the more deteriorated the emotional growth of that puppy will be.

At the end of the third critical period, the puppy is considered emotionally developed and ready to learn. But the puppy does not possess an adult brain at that age.


The trainability of a puppy is ripe and operating to capacity as he puppy enters the eighth week of life. Thus the puppy enters the fourth critical period of emotion, growth. What the puppy learns during this fourth critical period will be retained and become part of the dogs’ personality. If a puppy is left with its mother during the fourth critical period, its emotional development will be crippled. The puppy will remain dependent upon her but in her will find very little – if any – security.

When a puppy remains with the litter beyond this time and without adequate human contact – its social adjustment to human society will be crippled and what it learns will be learned from the litter mates.

Because a pups trainability and learning facilities are operating at full capacity during the fourth critical period, it is better that a puppy do his learning from his new owner. And learn he will!! The fourth critical period marks a time when a new puppy will learn at a fast and furious pace. And much of what he learns will stay with him a long, long time. What the puppy learns during the fourth critical period will help to shape him into the kind of dog he will be forever more ! !

That last paragraph is so important that every dog owner (and those contemplating getting a puppy) should read and reread it – and then read it again ! For the readers who acquired their dogs at six months or more, that paragraph may well explain some of the negative characteristics in the personality and behaviour of their dog.