Puppy Socialisation and Habituation (Part 1)
Why is it Necessary?
by David Appleby

One in five of the dogs that Dr Valerie O’Farrell (1986) studied while conducting research at Edinburgh (Royal Dick) University Veterinary School had a behavioural problem to a lesser or greater extent. A similar, but larger, American study fixed the figure at one in four. In one year my practice treated 773 dogs - 79 of them, that’s 10 percent, had problems of fearfulness towards people or the environment due to a lack of early socialisation or habituation and a further 4.5. percent were inept at relating to other dogs, again due to a lack of early socialisation. The problem is immeasurably greater than these figures suggest. Many dogs show a weakness of temperament or inability to cope when faced with a particular situation, without their behaviour becoming problematical enough for the owners to seek help from a behavioural counsellor.

Socialisation can be described as the process whereby an animal learns how to recognise and interact with the species with which it cohabits. In the wild this is likely to be limited to the animal’s own species, but for the domestic dog it includes other species such as man and cats. By learning how to interact with these the socialised dog develops communication skills which enable it to recognise, amongst other things, whether or not it is being threatened and how to recognise and respond to the intentions of others.

Habituation can be described as the process whereby an animal becomes accustomed to non-threatening environmental stimuli and learns to ignore them.

There is a sensitive period of development in which socialisation and habituation must occur and be properly completed if the dog is not to grow up to be maladjusted. The degree of deprivation a dog suffers in respect of socialisation and habituation will be reflected proportionately in the extent of maladjustment. Accordingly, a dog that has had no experience of a specific stimulus at the completion of the sensitive period will always be fearful of it; a dog that has had some exposure, but not sufficient, will be better adjusted, although not entirely sound; and a dog that has had adequate experience of the stimulus in the sensitive period will grow up to be "bomb proof". Dogs that grow up to be fearful because they have been subjected to stimulus deprivation can be improved by counter conditioning programmes, but the maxim prevention is better than cure was never more applicable than the first few weeks of a domestic animal's life.

The empirical evidence which shows the crucial importance of systematically socialising and habituating puppies during the critical period has been around for a long time. Few people interested in animals can be unfamiliar with the imprinting experiments of Konrad Lorenz, who, from the 1930’s onwards, recorded the fact that birds such as geese hand-reared from hatching became imprinted upon him and behaved towards him as to a parent of their own kind. In fact, Lorenz found that birds would imprint on virtually anything, even a flashing light, and treat it as mother. Significantly, birds that accepted Lorenz or a bird of another species as a surrogate parent would also recognise and accept other people or members of the adopter’s species. Birds are a special case because it is to their evolutionary advantage to recognise and follow the parent figure as soon after birth as possible.

Similar experiments have been conducted with mammals which have shown the important role socialisation has in species recognition and subsequent social and even sexual orientation. (There is a good story on record (Hediger, 1950) about a hand-reared bull moose that became amorous with his keeper rather than the female moose with whom he was supposed to be having an assignation).

Puppies, born blind and deaf and relatively immobile, are not fully able to start the process of species recognition at birth. However, an experiment on this question was conducted at Utrecht University where half of a litter of newborn puppies had no exposure to humans while the other half were exposed to a high level of human scent for just 30 seconds, after which the litter was kept in isolation from human contact for several weeks. When they were reintroduced to human company, it was found that the puppies that had received the early exposure to the researcher’s scent had a distinct preference for investigating people as opposed to investigating other environmental stimuli, whereas puppies that had not had the early experience showed no preference (Click here to read a communication about this research). In 1961 Freedman, King and Elliot identified the age of three weeks as the start of a puppy’s critical period, in terms of social/environmental interaction and the commencement of their capacity to develop social relationships. Significantly, this is the point in time when the puppy becomes truly mobile and can hear and coincides with increased electrical activity in the brain (Fox 1971a).

Michael Fox (1971a), a behavioural researcher, found that three week old Chihuahua puppies fostered individually in litters of four week old kittens would, at twelve weeks, prefer the company of cats over the company of their litter mates that had not been fostered. Additionally, the foster mother’s kittens were found to be able to relate to dogs whereas kittens from other litters who had not had a canine companion thrust upon them avoided contact with dogs. In the same year, Michael Fox (1971a) carried out a subtler but even more revealing experiment. Litters of puppies were split into three groups: one group of puppies were hand-reared from birth and received no canine contact; the second group were given an equal amount of canine and human contact; and the third group only experienced the company of other puppies and their dam. When these three groups of puppies were reunited those that had only experienced human interaction preferred the company of those who had received the same rearing experience. Similarly, those puppies who had been exposed to both human and canine company preferred the company of puppies of the same upbringing, as did the puppies only used to canine company.

Perhaps the most significant tests of all are those carried out in 1961 by Freedman, King and Elliot, which found that if puppies are kept in isolation from man and introduced at different ages their response to man deteriorates with age of first exposure. The results show that if puppies are introduced to humans for the first time between three to five weeks they will approach confidently, but those that are introduced between five and seven weeks of age will show increasing amounts of apprehension. Those puppies whose first experience of man is at nine weeks old or later will be totally fearful. In 1968 Scott concluded from his research into puppies kept in isolation from man until fourteen weeks “by fourteen weeks fear and escape responses have become so strong that any puppy raised in these surroundings acts like a wild animal”. Freedman, King and Elliot also found that puppies exposed to human company at fourteen weeks for the first time never developed a positive approach.

So far, the research cited has been concerned with aspects of socialisation, but what of habituation, i.e. environmental stimuli rather than social interaction? Experiments have been designed to reveal a puppy’s sensitive period for habituation, for example, puppies housed in conditions devoid of stimulation were placed in a test area with various articles for just half an hour at five, eight, twelve and sixteen weeks. These puppies were found to be increasingly keen to explore the items and to develop a preference for those that provided more complex stimuli. However, puppies who did not enter the test area until they were over eight weeks old tended to withdraw from rather than explore the items, and those who did not experience the test area until they were twelve or sixteen weeks old frequently became catatonic with fear (Fox 1971a). These results correlate with those from socialisation tests, reinforcing the theory that there is a critical period in which a puppy needs a stimulus-rich environment and social interaction.

Experiments have also shown that puppies, pre-stressed in early life, subsequently have a good capacity for coping with stress and those that do not receive the stressful experiences respond to stress less well as they mature (Fox). This has to be significant for anyone interested in dog training as it is essential to the success of training that a dog is able to cope with stress and has a positive response to complex stimuli and situations. Stress inhibits learning, and training requires of the dog the capacity to process complex stimuli.

One may ask why a fearful response develops if puppies don’t actually have an unpleasant or fear evoking experience associated with novel stimuli. The answer is that in their natural environment wild canids, specifically the wolf, to whom the domestic dog is related, have to be alert to danger, which means treating anything which they are not already familiar with as potentially hazardous. This means that wolf cubs have only a few weeks to develop positive associations with their own kind and immediate environment, after which they become increasingly cautious about things and situations not previously encountered. This saves them from blithely trotting up to something such as a snake and investigating it. The problem the domestic dog has is that it needs to become familiar with an enormous number of stimuli in a very short time so as to be able to live in and cope with the diversity of our world.

What practical applications do we have that bear out the research? Guide Dogs for the Blind, who, until 1956, used to rely on the donation of adult dogs which they took on approval to maintain their training stock. The success rate of these dogs fluctuated between 9 and 11 percent and it was recognised that this could be improved if the association could supervise the rearing of puppies. These were purchased and placed in private homes at between ten and twelve weeks old or even later. Things improved, but the results were not good enough. It was Derek Freeman, who pushed to have puppies placed in private homes at an earlier age to optimise socialisation and habituation during the critical development period. Derek had a strong belief in Scott and Fuller’s work and importance of early socialisation and habituation in the production of dogs that were best able to survive and perform in the world at large.

Derek found that six weeks was the best time to place puppies in private homes; any later critically reduced the time left before the puppies reached twelve weeks; but if puppies were removed from their dam and litter mates before six weeks they missed the opportunity to be properly socialised with their own kind, which resulted in inept interactions with other dogs in later life. The training success rate soared because of this policy, which was carried out in conjunction with the management of the gene pool via the breeding scheme Derek also pioneered. Annual success rates in excess of 75 percent became common. You might think that this is a special scheme for dogs with a special function. In fact, what the scheme provides is adult dogs with sound temperaments. These dogs coincidentally make the best material for guide dog training which does not start until they have been assessed at ten months or older. As a result of the breeding scheme, Derek Freeman also proved, if proof was needed, that you cannot dismiss the importance of genetic predisposition, i.e. the basic material required for good temperament can be produced through good breeding. Conversely, a lack of habituation/socialisation can ruin the chance of an individual developing a sound temperament, however good the genealogy.

There is another parameter within which dog owners, breeders and trainers etc. are obliged to work if a puppy’s potential is to be maximised. Research has revealed the fact that socialisation and habituation can wear off. J.H. Woolpy’s work with wolves in 1968 showed that adult captive wolves can be socialised with man with six months’ careful handling. This was highly skilled work carried out under very artificial conditions and remained specific to those conditions, and the team of skilled researchers involved reported that the experiment was very dangerous. The researchers found that if those wolves subsequently had less contact with them, their level of socialisation did not regress, but wolf cubs that were socialised in the optimum period, i.e. up to twelve to fourteen weeks, lost their socialising capacity when interaction with the researchers was withdrawn. If well-socialised puppies are placed in a kennel environment between three and four months of age, and left there in virtual isolation until they are between six and eight months of age, they will be shy of strangers and even of their caretakers if they have not handled them much (Michael Fox 1978). Therefore socialisation and habituation has to be continually reinforced throughout the animal’s juvenile period (Woolpy, 1968). In the dog this is from twelve weeks to maturity.

Let us consider a practical example of how this research affects the dog owner. A puppy, well-socialised with children until it is twelve weeks old, will require the socialisation to continue until it is mature, for the full benefits to be achieved. The same rule applies to a puppy who has been habituated to hearing traffic in the first few weeks of life but is then kept in a quiet rural environment until it is six or more months old, i.e. without periodic exposure and reinforcement it is likely to become fearful in the presence of traffic.

Everything stated so far leads to the question of why, if the benefits of socialisation and habituation are so irrefutably proven, are so many dogs under socialised and habituated? The reasons vary, but an examination of the early history of the seventy-nine dogs mentioned at the beginning of this chapter shows that they fall into two main categories (groups A and B):

A: Those that are retained by the breeder until they are well into, or even past, the critical period in an environment devoid of stimulation or with limited stimulation.

B: Those that are retained in the new owner’s household until the puppy’s vaccination programme is complete, often long after the critical period has passed.

Of those in group A we have to take into account the fact that breeders sometimes cannot find enough suitable homes quickly enough. Having said that, it is unfortunate that some breeders believe that most families are unsuitable to look after a puppy when it is six weeks old, although it is difficult to see what suddenly makes a family suitable when the puppy is eight, ten or twelve weeks old. All too often breeders, unaware of the harm they are doing, retain puppies well into and sometimes past the critical socialisation and habituation period so that they, the breeders, have time to choose which puppy or puppies they wish to keep for showing before launching the rest on the unsuspecting public. There is in essence nothing wrong in the breeder retaining a puppy for as long as they want, as long as they systematically ensure that each puppy is properly socialised and habituated as an individual. Each puppy needs to learn to cope with the environment without the support of its litter brothers and sisters and other dogs. Although this is possible, in practice, it is very time-consuming.

In group B, the implementation of vaccination programmes was a major contributor to the number of psychologically disturbed puppies. This was done in the name of the puppy’s physiological well-being. In the 1950’s a researcher named Baker showed that by twelve weeks of age, 98 percent of puppies have lost their maternally derived immunity to infection, which meant that if puppies were vaccinated at twelve weeks the vaccination would have a high take-up rate. To ensure that the puppies were not exposed to sources of infection in the meantime they had to be isolated in the owner’s household until there were at least twelve weeks old, and normally for two or more weeks after that. Once again, it was Derek Freeman who pioneered the way forward. He had an urgent need to socialise and habituate puppies within the critical period, i.e from six weeks onwards, but of course he had to ensure protection from infection. After consultation with Wellcome Guide Dogs for the Blind developed a policy of systematically vaccinating all puppies at six weeks and then repeating the innoculations at intervals to catch those few whose level of maternally derived immunity was too high for the vaccine to take on the first occasion. This removed the need for the first approach used which was to blood test every bitch for a titre count. In more recent years drug companies have recognised the need for early socialisation and therefore early vaccination. As a result vaccines designed for early use, with the additional benefit of an ability to overcome the immunity gap (the period of time in which the puppies’ maternally derived antibodies are too low in number to prevent infection but numerous enough to kill off any vaccine given, i.e. this type of vaccine will take as soon as the maternal antibodies are too low to resist infection).

Having looked at the theoretical aspects of early socialisation and habituation, what are the mechanics required to achieve it?

Instead of socialisation and habituation being a haphazard affair with experiences occurring at random, as is so often the case, a puppy’s exposure to environmental stimuli should be as systematic as possible to ensure the best chance of it developing a sound temperament and capacity to cope in all circumstances. A lot of responsibility lies with the breeder. Of course, it is the breeder who selects the genetic make-up of a dam and sire best suited to produce puppies of good temperament. The breeder’s role continues the moment a puppy is born, as it starts to get used to being handled and to the breeder’s scent. As the puppy and its litter mates group up, the breeder should increase the amount of interaction the puppies have with them and other people. If the breeder is a woman, for example, and she is the exclusive, or almost exclusive human contact the puppies have, they are likely to be less well adjusted towards men and children. It is sensible therefore, to invite men and children into the household to see and handle the puppies, particularly if the puppies remain with the breeder after they are six weeks old. It is, of course, important that veterinary advice on hygiene procedures is given.

It is not only important for breeders to socialise the puppies in their care, but they must ensure exposure to environmental stimuli. Not being able to take puppies off the premises in the first six weeks is limiting, but a puppy that has had regular experience of a television, vacuum cleaner, etc. will be more able to cope with the world than one that has been shut away in a quiet kennel or room. Audio tapes of environmental stimuli can also be made and played. Such techniques can be helpful if an older puppy is unwell or for some other reason cannot be taken outside the home.

© David Appleby