How Early Learning Critically Affects Your Reactive Dog

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How Early Learning Critically Affects Your Reactive Dog

September 26, 2022 Uncategorised 2

Working with dogs post-lockdown has reaffirmed the vital importance of early experience in how your dogs respond to the world later in life. Many reactive dogs, particularly those who are fearful or anxious, are affected by the early formation of their understanding of the world.

We are never in a position to turn back the clock. Understanding the fundamentals of early learning can, however, help us understand our dogs better. Then we may see why our dog may need a smaller world than the one we’d hoped for.

It also helps us prevent problems in future.

Before Early Development

From the moment our puppies are born, their brains are busy helping them prepare for life.

In fact, much evidence suggests that what happens even before that time can affect how our puppies will go on to experience the world.

A series of experiments by Oddist Murphree, an experimental psychiatrist working within the US Army in the 1960s and 70s, helped us understand the importance of parental emotional stability. Although inheritance is never perfect, anxiety as a trait showed evidence of heritability. In other words, anxious parents more frequently have anxious offspring. This is not genetic destiny: there is still variation. As we know, genes affect behaviour, but never perfectly. Even so, anxiety as a trait can be inherited.

Of course, anxiety can also be affected by mothering styles in early development. Cross-fostering also occurs where infants from anxious parents were raised by less anxious ones to account for this. What cross-fostering showed was that anxiety is set before nurturing begins.

Parental genes affect the emotional and behavioural traits of our dogs. As well as that, dogs are likely to be affected by pre-natal stress. Cortisol in the mother’s bloodstream can pass the placental barrier, sensitising unborn puppies to future stress. Other in utero factors are also believed to affect susceptibility to anxiety in later life. The position of puppies in the uterus is one of those.

Phylogenetic memory

Puppies also come with genetic memories, known as phylogenetic memory. Humans have this too. It is one reason we are often afraid of heights and small spaces which kill us much less frequently than cars and guns. These ancient memories tell us what we should fear.

Susan Mineka’s work since the 1980s has given us insight into these processes. Her work shows us, for instance, that it is much easier for monkeys to learn to be afraid of snakes than flowers. We also see that it is much harder for them to overcome that learning once they learned it. It is the same with humans and the same with dogs. Things that are a threat to our species are more easily feared. Those fears are harder to overcome.

It’s one reason dogs may fear thunder and loud noises, unfamiliar dogs and other people. Many dogs also show fear responses to things like snakes, despite having never encountered one in a negative way. Phylogenetic memory may have served us with an evolutionary advantage. It makes it easier for us to avoid things that would kill us over millennia.

Post-natal experience

As you have seen, genes matter. Having emotionally stable parents matters too. The mother’s experiences during pregnancy matter. Our own genetic memory contributes a little to how we process things that are dangerous to our species.

In cross-fostering experiments, researchers also learned that parenting styles also reduce tendencies to anxiety in later life. A puppy from an anxious line placed with a mother who is not anxious will grow up to be less anxious than those puppies staying with the anxious mother. However, early nurturing won’t produce puppies who are entirely emotionally robust. Genes and prenatal experience have already had their impact. It can be mitigated, however, by early nurturing.

Post-natal neural plasticity

Like other mammalian infants, puppies are born with more neural connections than they will ever use. The first eight weeks of a puppy’s life are about pruning them. What happens is actually neural die-off as much as neural growth.

A process called myelination also continues post-natally for a short period. Think of myelination as essentially high-speed fibre-optic nerve connections, compared to dial-up. Some bits of the brain rely on dial-up. Other bits become super-efficient at conducting messages along the neuron. The fatty myelin sheath basically insulates the nerve so that messages don’t fade or decay. Much of this process is about movement and proprioception. As puppies learn how to move, their bodies myelinate neural pathways making their nerves more efficient at sending messages.

Even when puppies are less than 10 days old, their brain is still working to process information, prune unused connections and myelinate those that are frequently used. Even simple things such as the food their mothers eat can become preferences for them too as they wean.

Sensory development

As senses develop, we tend to think of the puppy’s world as one that is opening up. That is absolutely true. We begin to expose them to a much wider range of odours, textures, objects and experiences beyond the whelping box.

However, what is also happening is that their window of curiosity and exploration is also closing.

In the 1950s and 1960s, behavioural biologists John Paul Scott and John Fuller ran the largest experiment to date about the heritability of behaviour in dogs. Taking five breeds, they looked at a range of different developmental milestones.

One of those was the onset of fear related to strangers. What Scott and Fuller documented was something that had been documented before. Past 14 weeks of age, puppies who had not experienced humans were so fearful of them that any ‘socialisation’ to help them accept humans was akin to taming processes. In short, the damage done is so intense by that period that the processes to get them to accept humans are very difficult.

Luckily, Scott and Fuller also found that there didn’t have to be much exposure for puppies to become social to humans. 10 minutes a day was enough. They did find, though, that it was gradually harder and harder for puppies to accept strangers. At 6 weeks, the puppies showed no fear. By 8 weeks, some did. By 10 weeks, many did. At 12 weeks, most did.

Other developmental processes

Puppies have a lot to process in a very short period. From 5 weeks to 8 weeks, they begin to learn that objects (like family!) are permanent and to feel distress when they know family members are out of sight. Their senses refine. Neural pruning continues. Their developmental window begins to close. They begin to learn how to cope when they can’t get what they want, and they begin to learn how to act less out of innate instinct and reflexes and more as a result of learning. Even simple things like learning to cope with mild hunger are also part of their development.

During this time, the interplay between genes and learning is complex and intricate. At this age, collies begin to eye and stalk sheep, pointers begin to point, terriers begin to grab and shake and pull. Some of these behaviours are more susceptible to dopamine and to emotional tagging meaning that they are easier to learn than other things. Puppies can also be easily sensitised to the environment during this time.

Physiological, emotional and behavioural development is all concentrated into a tiny block of time.

The importance of good breeders and fosterers

Since so much of a puppy’s development happens between birth and 8 weeks, it’s vital that this is overseen by capable, careful people. If we want robust dogs who can cope with a noisy, busy modern world, we also need to pay attention to the puppy’s parents and grandparents. Good breeders and fosterers will work to help their puppies develop normally and to make sure they experience life before their developmental windows begin to narrow.

On the other hand, it’s vital that we understand the damage done by puppy mills and by individuals who do nothing to ensure their puppies are equipped for life. Sadly, since breeding and puppy fostering are largely unregulated, it is too common that puppies can be raised in spare rooms, sheds, outbuildings and garages. Well-meaning people who do not understand development do not understand that in doing this, they are contributing to problems further along the line. A delightful ‘puppy palace’ made out of a purpose-built out-building is sadly going to limit the puppy’s experience of the home.

For instance, if we take simple things like the sound of the washing machine. These everyday household noises will more readily startle a puppy of 9 weeks if they have never encountered one compared to a puppy of 5 weeks. The same is true of car journeys, handling, manipulation and noises beyond the home. It is also true of experiences with other dogs and with unfamiliar humans.

Understanding initial familiarisation

The early learning period is often called socialisation. This term is not particularly appropriate because it implies interaction between social individuals, and the initial learning period is not simply about the kind of social interactions that give us a positive world view.

As mammals develop, they’re also experiencing initial habituation to the world. For dogs, they’re learning about televisions, phones, washing machines, brooms, vaccuum cleaners, doorbells, stairs…

As you can see, calling this ‘socialisation’ is not particularly appropriate since it is not a social experience.

Science also gives us another word: habituation.

Habituation is a simple process by which we get used to experiences. For instance, if you move from the countryside to the town, you will habituate to noise levels, traffic, car horns and even the odour of the town. Habituation is also not particularly the right word for what happens during early development, since habituation is a relatively temporary process.

As we adapt to new environments, our brains use habituation processes to help us cope with sensory overload. What was once significant and salient becomes part of the background noise.

Initial familiarisation does not seem to work like this in that it is much longer lasting and sometimes permanent.

What happens when we experience situations in early development is that habituation seems to be much more permanent. It is as if those initial experiences help contribute to our world view. In psychology, this world view is known as a schema, and it helps us process the world.

Development of schemas

Let’s imagine that, during our early development, we experience loud noises. Our brain is still open, exploratory and curious. We learn to accept that loud noises simply exist. Because our brains are not yet fearful, these experiences are not coded by the amygdala as being significant.

When we experience other loud noises, they fit into that schema. It’s just a loud noise. Nothing to be afraid of, even if it did startle you.

As our openness to experience closes and we lose the psychological inoculation against fear, those schemas help us make sense of other potentially scary phenomena.

For example, puppies are not born afraid of human hands.

If they experience human hands before fearfulness of novelty becomes the default setting, then they will understand human hands are nothing to be afraid of, generally speaking.

Sure, there may be exceptions, but our schemas help create general rules. Noises are nothing to be afraid of. Human hands are kind. Other dogs are fun.

When we have bad experiences, our initial schemas help us learn exceptions.

On the other hand, if our early experiences are poor or non-existent, then our general rules are to be wary. Our puppies may then sensitise easily to new phenomena.

Puppyhood is about developing these mental schemas or world views that categories of things are safe or scary.


Sensitisation is another simple and temporary form of learning. It simply means behaviour that becomes more intense or of longer duration the longer we are exposed to something. For fearful responses, for example, when our dogs are sensitised, their responses are more intense and more dramatic. Many of our reactive dogs have been sensitised to a variety of triggers.

Sensitisation serves a useful purpose in the right place.

Habituation and sensitisation are both processes that help us make sense of the world around us. They help us decide what is relevant and what can be ignored. They are particularly relevant for orienting responses and attentional responses. In other words, habituation and sensitisation help explain how environmental stimuli get our attention. Since reactive dogs are often those dogs who are highly responsive to environmental stimuli, understanding these two processes is critical to our work.

How do brains decide whether to habituate or sensitise?

For puppies under the age of 6 weeks, they are psychologically buffered from internalising much stress or fear. Things that they experience during this time will become normalised. They will become part of our dog’s world view or schemas.

As they develop, puppies still maintain the ability to habituate or sensitise.

So how can we know if our young dogs are likely to get used to triggers and ignore them, or if they are likely to have stronger and more frequent responses?

Essentially, it comes down to three things: our dog’s personality or temperament and how emotionally stable they are; whether the thing the dog will encounter is a common fear for their species, and finally, our dog’s emotional state when they encounter potentially scary stimuli.

What we know about sensitisation is that it is much more likely if we are emotionally aroused. That can be positive emotions like joy and excitement. It can also be negative emotions like anxiety or frustration.

When we encounter experiences when we are emotionally aroused, they are more likely to be tagged with those emotions as our brain decides they are important. Emotional arousal primes us to sensitise.

Exciting sensitisation with young dogs

If you take a border collie for example, and imagine their learning journey as they sensitise towards the movement of cars, it would have several key components:

The dog did not experience many cars in their sensitive development period prior to 8 weeks.

Cars were never normalised through initial familiarisation.

When the dog encountered cars, they were in a state of excitement or joy.

Seeing the flash of movement awoke specific instincts within the dog and the emotional state flagged them as relevant rather than irrelevant.

The next time they see a car, they are primed to respond more intensely to it, particularly if this has been rewarding at a neurochemical level.

Perhaps worse still, once sensitised, we become more easily sensitised to that trigger in the future, even if we had undergone exposure therapies.

It’s natural then for the guardian to put the dog on a lead, adding to the frustration of a young dog who perhaps has not been taught yet how to cope with that emotion.

Fearful sensitisation with young dogs

This time, we’ll look at a case with a dog who grew up during lockdown and explore the reasons why this dog sensitised to unfamiliar dogs:

The dog did not experience or see other dogs outside of their family group in their sensitive development period prior to 8 weeks.

Strange dogs were never normalised through initial familiarisation

When the dog did encounter other dogs, they were restrained and panicking at the vet.

Seeing the other dogs awoke specific fear responses that are part of their species-specific genetic memory.

The emotional state and relevant triggers meant that the puppy’s response was more intense and they reacted strongly.

Because of the emotional arousal, the amygdala tags the experience as relevant, telling the sensory systems to look out for this threat in the future.

This makes it more easy for dogs to recall that experience and for that experience to affect their world view or schema of unfamiliar dogs.

Because they have been sensitised, they are now more easily sensitised again in the future, even if you do work to help them learn to habituate to unfamiliar dogs.

Concluding thoughts

Many dogs develop fears or frustration as a result of their intial exposure to triggers that are likely to be relevant to them. As a result of this, they construct a world view based on this that is then ‘cemented’ to some degree. Everything past this is simply learning exceptions to the rule.

Instead of learning for instance that they’ve met or seen a good number of adult dogs who’ve helped them develop a world view that strange dogs are irrelevant or benign, they learn to be afraid of strange dogs. When a dog with a positive world view has a bad experience, they learn a single exception. When a dog with a negative world view has a positive experience, they also learn a single exception. Instead of understanding that strange dogs are mostly okay and that one or two dogs are not, they understand that strange dogs make them feel afraid, and one or two dogs are friendly.

We should remember that negative world views do not simply come from poor experiences after the age of 6 weeks or so, but from the absence of positive experiences. When our puppies grow up without experiencing anything remotely like the things they experience in later life, their default position (depending on their personality) may always be: ‘new stuff bad’.

Fighting back against this can be challenging and many of us come to understand that we need to accept the limitations of the small world in which our dog feels comfortable and safe.

Further reading

This post has been the last of ten looking at the most common factors underpinning canine reactive behaviour:










In the next post, we look at ways that you can create an individualised profile of your dog so you can find ways to make a difference.

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  1. […] this lucky dog was in the happy period between early socialisation and the onset of adolescence. We know that traumatic experiences are encoded differently during […]

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