Socialisation and other critical periods
In 1945 an extensive programme of research was initiated at the Roscoe B. Jackson Memorial Laboratory at Bar Harbor, Maine into the relationship between heredity and social behaviour in dogs. Concluding that there are particular periods in early development when puppies are unusually sensitive to environment influences and therefore especially vulnerable to permanent psychological damage.
According to the findings the early development of the dog can be divided into a series of four “natural” stages or periods however it is also suggested that the “prenatal period” should be added since
it appears that long term effects on behavioural development may be produced in mammals by events occurring in utero . Studies of rodents indicate that transplacental , maternal influences may affect the subsequent behaviour of the offspring. For example subjecting females to stressful experiences during pregnancy tends to render their offspring more emotional or reactive in test situations later in life and more emotional females tend to give birth to more emotional offspring independent of genetic influences. In the altricial species such as the dog, the immature state of the fetal nervous system makes it unlikely that significant prenatal effects on behaviour result from learning. Rather that any changes in emotionality, for instance are probably caused by direct effects of maternal corticosteroid hormones on the development of the foetus’s subsequent physiological responsiveness to stress.
The neonatal period covers approximately the first two weeks of life. During this period the puppy is still comparatively helpless and dependant on it’s mother. Although sensitive to tactile stimuli and certain tastes and possibly smells their motor abilities are very limited and neither their eyes or their ear canals are open or functional. Because of the immature state of their neurosensory systems it was originally assumed that canine neonates were largely incapable of associative learning . However it has now been shown that neonatal puppies can learn simple associations although slowly compared to older puppies and only within their own limits of their own rather specialized sensory and behavioural capacities. On the basis of this specialization it was concluded that learned effects of early experiences in the neonatal period are unlikely to carry over to later periods to any appreciable extent. Nevertheless it is well established that short periods of daily handling as well as a variety of other strong or noxious physical stimuli can have marked long term effects on the behavioural and physical development of some mammalian neonates, including puppies. These effects include accelerated maturation of the nervous system, more rapid hair growth and weight gain, enhanced development of motor and problem solving skills and earlier opening of eyes. In behavioural terms canine neonates exposed to varied stimulation from birth to five weeks of age were found to be more confident, exploratory and socially dominant when tested later in strange situations than un-stimulated controls. To account for these sorts of effects it is suggested that early handling and stress produces an adaptive change in the animals pituitary - adrenocortical system that enables it to cope more effectively with stressful situations in later life.
The extent to which such effects prevent or contribute to the development of behavioural problems in domestic dogs is at present unknown.
The transitional period is a short time frame lasting no longer than a week starting when the eyes and ears open and the first appearance of the auditory “startle“ response to loud noises. The locomotor skills change from a crawl to a walk, albeit clumsily and this is usually the time that puppies are mobile enough to start leaving the nest box, anogenital licking by the mother is no longer required to stimulate elimination, this is also the time they first notice others and start to play fight with littermates also displaying social signals such as growling and tail wagging and start eating semi-solid foods. It is a marked period of rapid transition or transformation during which patterns of behaviour associated with neonatal existence disappear and are replaced by those more typical of later puppy-hood and adult life. In terms of learning and the effects of early experience the transitional period more or less resembles a continuation of the neonatal stage. Puppies performance on both classical and operant conditioning tasks show a steady improvement at this age although rates of learning and the stability of conditioned responses do not reach adult levels until four to five weeks of age. (Serpell 1995)
The socialisation periodis the third critical period and probably the single most important time in the dogs life relative to social interactions. Beginning around three weeks of age when the puppy becomes capable of seeking nonmaternal social interaction. It lasts until infantile behaviour patterns end and environmental interactions become more attractive than social ones - around twelve weeks of age. A lot happens during this time relative to the maturation of physical, neurologic and behavioural features. Motor skills mature to allow active interaction and reaction. The nervous systems approaches adult-like patterns and stable learning begins.
As the socialisation period is so significant it is important to understand the various types of learning that take place during this time. The most significant lesson relative to humans is species identification. By raising puppies in solitary isolation, paired isolation , and cats or around people and then testing at various intervals, investigators have learned much about the importance of puppies being with other dogs and people. At three-five weeks puppies will actively approach people that are strangers. Shortly thereafter avoidance of strangers begins and slowly escalates until it peaks at twelve to fourteen weeks of age. This progressive avoidance helps to protect the youngsters against predators. Although there are breed differences in response, puppies that are completely isolated from humans until fourteen weeks of age are forever uncomfortable around people usually attempting to avoid interactions and act fearfully if escape is not possible.
If raised around humans or cats without the presence of any other dogs for fourteen weeks the puppy tends to avoid its own species both socially and sexually.
A hand reared puppy is more apt to show inappropriate social behaviour towards other dogs from avoidance to aggression.
Puppies isolated in cages from eight weeks to six months of age or kept in kennels beyond fourteen weeks of age show a generalised fear of different environments. Those kept in relatively bland surroundings showed behaviours aberrations in new, more complex environments. The institutionalisation syndrome or kennelosis is expressed as a lack of interest in exploring a new environment showing timidity or other inappropriate response to strangers.
The actual amount of contact needed for socialisation to a species is probably quite brief and can be influenced by outside factors. Food rewards are not necessary for socialisation nor does punishment inhibit it, however hunger and it’s gratification will speed up the process.
A study was carried out on the effects of punishment at different times during socialisation. Puppies raised with normal human contact were divided into three groups of five - six weeks, eight - nine weeks and twelve - thirteen weeks of age. Each group were first tested for their approach response to humans. If the puppies did approach they were given a mild electric shock.
The puppies aged five to six weeks who actively approach the humans ran away when shocked. When retested a few weeks later the same puppies actively approached again as if they had no memory of the first episode.
The puppies aged eight to nine weeks of age also retreated from the shock and when retested would not approach the person. Because of the start of stable learning at around eight weeks of age this group of puppies remembered the trauma and chose to avoid a similar situation. Traumatic episodes can desocialise a dog. At this age a toe accidentally stepped on or a painful vaccination may be sufficient for the puppy to become cautious of an individual or similar group of individuals.
The eldest group of puppies those twelve to thirteen weeks continues to approach the human even though they received a shock. This continued approach indicated a strong emotional attachment towards humans.
The juvenile period is the fourth and last critical period extending from twelve weeks to sexual maturity. The lessons of socialisation will need occasional reinforcement throughout this period and afterwards or they can be forgotten in six months. If the original learning did not occur the dog will be socially handicapped throughout the remainder of it’s life. Environmental exploration increases during the juvenile period and if the puppy has not been around people it will manifest avoidance. The basic learning capacity is fully developed and the speed for conditional learning begins to slow perhaps because of the interference of previous learning. (Beaver1999)
The results of the Bar Harbor studies of socialisation and subsequent related investigations gave rise to various practical recommendations regarding husbandry and training of domestic dogs. In particular, two basic rules for producing a well balanced and well adjusted dog were proposed.
Firstly that the ideal time to produce a close social relationship between a young dog and it’s human owner is between six and eight weeks of age and that this is therefore “the optimal time to remove a puppy from the litter and make it into a house pet.
Secondly that puppies should be introduced at least in a preliminary way to the circumstances and conditions they are likely to encounter as adults preferably by eight weeks of age and certainly no later than twelve weeks. (Serpell 1995)
Interactions should be supervised initially to promote positive experiences and all positive responses to stimili should be praised or rewarded. Negative experiences should be avoided when at all possible throughout all four periods of socialization which may mean that activities involving young dogs need careful planning to ensure the dogs are grouped with others at the same level of socialization or individual time be given to encourage those who are lacking skills to attain them.
Beaver B, (1999), Canine Behaviour: A Guide for Veterinarians, USA, Saunders.
Serpell J, (1995) The Domestic Dog. Cambridge University Press, Cambridge, UK.
In 1945 an extensive programme of research was initiated at the Roscoe B. Jackson Memorial Laboratory at Bar Harbor, Maine into the relationship between heredity and social behaviour in dogs. Concluding that there are particular periods in early development when puppies are unusually sensitive to environment influences and therefore especially vulnerable to permanent psychological damage.
According to the findings the early development of the dog can be divided into a series of four “natural” stages or periods however it is also suggested that the “prenatal period” should be added since
it appears that long term effects on behavioural development may be produced in mammals by events occurring in utero . Studies of rodents indicate that transplacental , maternal influences may affect the subsequent behaviour of the offspring. For example subjecting females to stressful experiences during pregnancy tends to render their offspring more emotional or reactive in test situations later in life and more emotional females tend to give birth to more emotional offspring independent of genetic influences. In the altricial species such as the dog, the immature state of the fetal nervous system makes it unlikely that significant prenatal effects on behaviour result from learning. Rather that any changes in emotionality, for instance are probably caused by direct effects of maternal corticosteroid hormones on the development of the foetus’s subsequent physiological responsiveness to stress.
The neonatal period covers approximately the first two weeks of life. During this period the puppy is still comparatively helpless and dependant on it’s mother. Although sensitive to tactile stimuli and certain tastes and possibly smells their motor abilities are very limited and neither their eyes or their ear canals are open or functional. Because of the immature state of their neurosensory systems it was originally assumed that canine neonates were largely incapable of associative learning . However it has now been shown that neonatal puppies can learn simple associations although slowly compared to older puppies and only within their own limits of their own rather specialized sensory and behavioural capacities. On the basis of this specialization it was concluded that learned effects of early experiences in the neonatal period are unlikely to carry over to later periods to any appreciable extent. Nevertheless it is well established that short periods of daily handling as well as a variety of other strong or noxious physical stimuli can have marked long term effects on the behavioural and physical development of some mammalian neonates, including puppies. These effects include accelerated maturation of the nervous system, more rapid hair growth and weight gain, enhanced development of motor and problem solving skills and earlier opening of eyes. In behavioural terms canine neonates exposed to varied stimulation from birth to five weeks of age were found to be more confident, exploratory and socially dominant when tested later in strange situations than un-stimulated controls. To account for these sorts of effects it is suggested that early handling and stress produces an adaptive change in the animals pituitary - adrenocortical system that enables it to cope more effectively with stressful situations in later life.
The extent to which such effects prevent or contribute to the development of behavioural problems in domestic dogs is at present unknown.
The transitional period is a short time frame lasting no longer than a week starting when the eyes and ears open and the first appearance of the auditory “startle“ response to loud noises. The locomotor skills change from a crawl to a walk, albeit clumsily and this is usually the time that puppies are mobile enough to start leaving the nest box, anogenital licking by the mother is no longer required to stimulate elimination, this is also the time they first notice others and start to play fight with littermates also displaying social signals such as growling and tail wagging and start eating semi-solid foods. It is a marked period of rapid transition or transformation during which patterns of behaviour associated with neonatal existence disappear and are replaced by those more typical of later puppy-hood and adult life. In terms of learning and the effects of early experience the transitional period more or less resembles a continuation of the neonatal stage. Puppies performance on both classical and operant conditioning tasks show a steady improvement at this age although rates of learning and the stability of conditioned responses do not reach adult levels until four to five weeks of age. (Serpell 1995)
The socialisation periodis the third critical period and probably the single most important time in the dogs life relative to social interactions. Beginning around three weeks of age when the puppy becomes capable of seeking nonmaternal social interaction. It lasts until infantile behaviour patterns end and environmental interactions become more attractive than social ones - around twelve weeks of age. A lot happens during this time relative to the maturation of physical, neurologic and behavioural features. Motor skills mature to allow active interaction and reaction. The nervous systems approaches adult-like patterns and stable learning begins.
As the socialisation period is so significant it is important to understand the various types of learning that take place during this time. The most significant lesson relative to humans is species identification. By raising puppies in solitary isolation, paired isolation , and cats or around people and then testing at various intervals, investigators have learned much about the importance of puppies being with other dogs and people. At three-five weeks puppies will actively approach people that are strangers. Shortly thereafter avoidance of strangers begins and slowly escalates until it peaks at twelve to fourteen weeks of age. This progressive avoidance helps to protect the youngsters against predators. Although there are breed differences in response, puppies that are completely isolated from humans until fourteen weeks of age are forever uncomfortable around people usually attempting to avoid interactions and act fearfully if escape is not possible.
If raised around humans or cats without the presence of any other dogs for fourteen weeks the puppy tends to avoid its own species both socially and sexually.
A hand reared puppy is more apt to show inappropriate social behaviour towards other dogs from avoidance to aggression.
Puppies isolated in cages from eight weeks to six months of age or kept in kennels beyond fourteen weeks of age show a generalised fear of different environments. Those kept in relatively bland surroundings showed behaviours aberrations in new, more complex environments. The institutionalisation syndrome or kennelosis is expressed as a lack of interest in exploring a new environment showing timidity or other inappropriate response to strangers.
The actual amount of contact needed for socialisation to a species is probably quite brief and can be influenced by outside factors. Food rewards are not necessary for socialisation nor does punishment inhibit it, however hunger and it’s gratification will speed up the process.
A study was carried out on the effects of punishment at different times during socialisation. Puppies raised with normal human contact were divided into three groups of five - six weeks, eight - nine weeks and twelve - thirteen weeks of age. Each group were first tested for their approach response to humans. If the puppies did approach they were given a mild electric shock.
The puppies aged five to six weeks who actively approach the humans ran away when shocked. When retested a few weeks later the same puppies actively approached again as if they had no memory of the first episode.
The puppies aged eight to nine weeks of age also retreated from the shock and when retested would not approach the person. Because of the start of stable learning at around eight weeks of age this group of puppies remembered the trauma and chose to avoid a similar situation. Traumatic episodes can desocialise a dog. At this age a toe accidentally stepped on or a painful vaccination may be sufficient for the puppy to become cautious of an individual or similar group of individuals.
The eldest group of puppies those twelve to thirteen weeks continues to approach the human even though they received a shock. This continued approach indicated a strong emotional attachment towards humans.
The juvenile period is the fourth and last critical period extending from twelve weeks to sexual maturity. The lessons of socialisation will need occasional reinforcement throughout this period and afterwards or they can be forgotten in six months. If the original learning did not occur the dog will be socially handicapped throughout the remainder of it’s life. Environmental exploration increases during the juvenile period and if the puppy has not been around people it will manifest avoidance. The basic learning capacity is fully developed and the speed for conditional learning begins to slow perhaps because of the interference of previous learning. (Beaver1999)
The results of the Bar Harbor studies of socialisation and subsequent related investigations gave rise to various practical recommendations regarding husbandry and training of domestic dogs. In particular, two basic rules for producing a well balanced and well adjusted dog were proposed.
Firstly that the ideal time to produce a close social relationship between a young dog and it’s human owner is between six and eight weeks of age and that this is therefore “the optimal time to remove a puppy from the litter and make it into a house pet.
Secondly that puppies should be introduced at least in a preliminary way to the circumstances and conditions they are likely to encounter as adults preferably by eight weeks of age and certainly no later than twelve weeks. (Serpell 1995)
Interactions should be supervised initially to promote positive experiences and all positive responses to stimili should be praised or rewarded. Negative experiences should be avoided when at all possible throughout all four periods of socialization which may mean that activities involving young dogs need careful planning to ensure the dogs are grouped with others at the same level of socialization or individual time be given to encourage those who are lacking skills to attain them.
Beaver B, (1999), Canine Behaviour: A Guide for Veterinarians, USA, Saunders.
Serpell J, (1995) The Domestic Dog. Cambridge University Press, Cambridge, UK.
