Why Arousal Matters with Anxious and Fearful Dogs

Revolutionise Your Dog Training

Why Arousal Matters with Anxious and Fearful Dogs

October 24, 2023 Uncategorised 0

We all know that unpleasant experiences are not created equal. This is especially true for our dogs. If you have a dog who panics at the vet, you will probably have experienced this first hand. There are plenty of experiences in life that are not the end of the world, but our dogs categorise those events as just as challenging as if they were life-threatening.

Sometimes our dogs sensitise to experiences rather than habituating. This is especially true for our anxious dogs


Sensitisation and habituation are central processes in life. Think of traffic noise, for example. If you are used to quiet surroundings, when you move to a place where there is a lot of traffic noise, you will hopefully get used to it eventually. Traffic noise isn’t particularly unpleasant, but few of us would probably say we enjoy it.

Habituation may be only a temporary form of learning, but it is a very important one. Getting used to things is required in many areas of life. This allows us to sift through the millions of pieces of sensory information our bodies receive so that we can pay attention to things that matter. If we move to a high-traffic area, the occasional beep or moment of intensely heavy traffic will still stand out. Instead of startling every time we hear a car, we just get used to it.

Normally, there is a reduction or a decline in response. Instead of jumping every time we hear a car, we get used to it.

We saw the effects of habituation during lockdown in the Covid-19 pandemic. I lived under a busy flight path and when most planes were cancelled, we had twelve weeks of almost silent skies. My dog Flika, who had already been a little sensitive to low-flying or particularly noisy air traffic, had time for her responses to settle. She relaxed and did not have to shout at the skies all the time.

When the planes returned, however, they were very noticeable. She sensitised to them instead of habituating to them. Instead of blending in as our sensory system gets used to them, instead of only paying attention to the loudest as she had before, she was reacting to all of them.


When we sensitise, we fail to habituate. We respond more strongly than ever. There is an increase in response.

These responses are usually involuntary or automatic, rather than conscious choices we make.

The same is true for our dogs.

Most dogs who live on a main road will hopefully get used to traffic, just as we do. After a time, it’s just background noise. I found this when I moved from living alongside a busy road with steady but speedy traffic. When I moved with my dogs to a quieter village, we were living on a corner where traffic had to slow down because it was a very tight bend. This meant getting used to lots of very slow-moving traffic. Some of that traffic could be particularly noisy because there was a lot of agriculture in the area. Tractors in particular found that turn to be very tight.

Initially, one of my dogs was very sensitive to this change. Having lived in a place where there had been more traffic but it had moved at speed, he struggled with the change for a little while. Over time, he habituated as you would hope. His initial habituation to cars was actually only to fast-moving traffic. He had never had to get used to slow-moving traffic. Although he was sensitive at the beginning, he habituated after a few days.

Some dogs, however, do not habituate. They sensitise even further.

Why we habituate

We habituate to very specific things relatively quickly. Every morning, I enjoy a cup of freshly brewed coffee. Yet the first sip is always the best. The reason the second and third sip aren’t quite as pleasurable is because I’ve got used to the taste.

You can also see that habituation is temporary. Every morning, that first sip of coffee is enjoyable again. Perhaps habituation is one reason that we’ve always got room for dessert. Changing taste and texture breaks the cycle of habituation to flavour.

Habituation gives us room to keep our senses open to novelty or change. If you’ve found yourself scrolling on social media, you have fallen victim to the fact that change is appealing. If you had nothing but the same kind of content, you’d probably habituate quickly and find it boring. Clearly, social media algorithms understand this and keep it varied!

Habituation helps our attention. We cannot pay attention to everything: we would need much, much larger brains than we already have. Being able to habituate helps us prioritise our attentional processes, so habituation and attention are closely linked in many ways. More familiar things are much less stimulating. This is why we can think of habituation as ‘familiarisation’ or ‘getting used to things’. We can then pay more attention to novel things.

Instead of startling every time we hear a car or a plane, we can pay attention to other things instead.

Why we sensitise

Sometimes, we’re not exactly sensitising when we start to notice things again. Habituation is temporary, and when we don’t experience things for a while, then they are noticeable for a while until we habituate again. At the beginning of the hunting season in France, regular gunshot is very noticeable after that period where there was no gunshot. This is not to say that we’ve sensitised: it’s just to say that we had a period of time where we didn’t experience whatever it is that we notice.

Sensitisation is much more likely when we’re already aroused. Think about a situation where you are shopping in a supermarket and someone taps your arm to tell you that you’ve dropped your purse. You’d probably respond to that tap, turning around to notice the person, but because you are unlikely to be aroused in a supermarket, you are unlikely to sensitise to it.

Arousal is simply our level of wakefulness or preparedness. Being in a supermarket is probably not that arousing for most of us.

Yet imagine the situation if you are walking down the street late at night in the dark. You are highly aroused and wakeful, because you feel like you may be in potential danger. Were somebody to touch your arm in those circumstances, you would be much more likely to have a strong startle response and to sensitise.

It may take you a really long time to return to baseline. Although this is a normal phenomenon, because sensitisation is as temporary a form of learning as habituation, we can think of this as de-sensitisation.


Desensitisation is a normal phenomenon. Imagine your dog is a little worked up by car journeys or by fireworks. Perhaps they feel a bit sick on a car journey or they’re a little spooked by a very loud rocket. Perhaps they sensitise and become reluctant to get into the car or they startle when they hear a firework.

Because we (hopefully) don’t live around fireworks all the time, or go in the car all the time, our response will eventually return to normal. Instead of a heightened, rapid response to very low levels of things, we will probably tolerate low levels and respond ‘normally’ – whatever normal might be.

A good break can actually be a time to re-set for humans and animals who have sensitised to things. Between January and September in the UK, there are much less frequent fireworks and so it’s normal for a lot of dogs to ‘reset’ during this time. I notice this with my noise-sensitive dog. Her behaviour around storms, gunshot and fireworks intensifies the longer the season lasts. Having a break helps her reset and desensitise.

We can help this process along by gradual exposure at low levels over spaced-out trials.

Why do some of our dogs sensitise so strongly?

There are many things that make us more sensitive to the environment and more prone to stronger reactions. One of the major factors is arousal. Our level of arousal before things happen makes us more likely to sensitise.

That then begs the question, ‘what causes arousal?’ and that is more complex. Normal circadian hormonal fluctuation throughout the day can contribute to wakefulness and responsiveness to particular stimuli. Of course, developmental stages can make us more prone to sensitise as well. Our cognitive processes are affected by hormonal fluctuations and developmental period too. Ask any teenager or woman in perimenopause!

Mood states and uncertainty can also contribute to sensitisation. Because they increase watchfulness and alertness, these factors make it much more likely that we will sensitise rather than habituate. Arousal intensifies our experiences, whether that is good or bad.

In fact, although we’re considering situations in which our dogs sensitise to unpleasant things, we should also be mindful that if they are aroused when they encounter very exciting things, this can have significant fallout. Seeing young border collies highly aroused on a walk sensitise to the movement of other dogs, of cars, of bicycles or of humans is often not as reversible or temporary as we would hope.

That arousal heightens pleasure has long been known in adult sexual relationships. That arousal heightens startle responses has long been known by the horror film industry.

Typical problems caused by sensitisation

Once we have sensitised to a stimulus, even if we desensitise, this actually makes it even easier for us to sensitise again in the future. We can rapidly become just as sensitive to the same things more quickly the next time around. That fuels our anticipation, which fuels arousal which fuels sensitisation.

Imagine that young border collie who has sensitised to the movement of cars. Now, he may well be anticipating cars because they made him feel so good last time.

Or imagine a dog who has become sensitive to the car. Whenever the dog now sees the car, the anticipatory apprehension will fuel arousal which will fuel sensitisation if he’s forced to travel again.

It works on both sides of the coin: pleasant and unpleasant.

For our dogs who are very sensitive to prey species or movement, that initial encounter can make our lives a nightmare. Perhaps our dog is spending all day perched on the couch, waiting for a squirrel to appear. When the squirrel finally does, because our dog is so aroused already by the anticipation, they resensitise all over again.

Currently, a neighbour’s cat keeps using my wall as a shortcut. We have lived here for two years (thankfully) without cats hopping the wall. The last three days, my dog (who is very sensitised to cats due to her experience before she came to me) has noticed the cat. Now, I have put up a screen. I do not want her to sensitise again and spend all day frustrated by the window.

Avoiding sensitisation

The best way to avoid sensitisation is to be conscious of your dog and to behave pre-emptively. Do not do things that are bound to be pleasant or unpleasant when your dog is highly aroused.

Many dogs, for example, are sensitive to the vet. They act as if the vet is their mortal enemy, and that one small injection is much more painful than it is for more relaxed animals. We contribute to this with anxiety in the waiting room and by rushing things. Were we to wait a little and reassure the animal, we’d probably be dealing with far fewer cases of sensitivity to animal health professionals.

Many dogs also become very sensitive to things that are highly exciting. When they initially encounter other dogs, people, other animals or moving vehicles when they are highly aroused, they are much more likely to find it ALL the fun. We can avoid this by taking care during the early socialisation period and making sure exposure to things that are likely to be highly stimulating for them only happen when they are relaxed.

If our dog has already sensitised to pleasant or unpleasant experiences, we need to be mindful that they will find it easy to re-sensitise again in the future, especially when they are aroused. Teaching dogs to relax and to settle can be a crucial ingredient in our success.

We can also make sure we set up the environment carefully so they are not exposed to scary things at full intensity or for long duration. This arousal is called potentiation and it simply means it is much easier for us to sensitise.

The role of odour

Odour is particularly relevant here: odour has been used to potentiate responses – making them bigger if you will. Should a lab rat smell the odour of a predator like a cat before undergoing an experiment to cause a fear response, it is much easier for them to sensitise to the things that predict the unpleasant experience.

We aren’t always aware of this with our dogs. Sometimes odour can be a powerful way of increasing arousal, preparing the body for good and bad stuff. The odour of threatening dogs or predators may well prime our dogs to be afraid. The odour of prey species may well prime our dogs to struggle to cope when the squirrel finally pops into view.

Because we are insensitive to the odours our dog can experience, we certainly should pay attention to our dog’s body language when reading their responsiveness and activity level. We also do not know how dogs interpret the odour of various stress hormones in the vet surgery and whether this could prepare them to sensitise to the vet.

It may be a good time to take our time in preparing our dog for such events, but if we do so in a place filled with the smell of fear, we don’t really know if we’re just causing increased anxiety and uncertainty.

Getting things right can be tough.

A final word

Next week, I will be exploring habituation – often the golden goal we are looking for with our fearful dogs. When our dogs are used to the world, life is much easier for them.

If you are a dog trainer or behaviour consultant working regularly with anxious or fearful dogs, you may enjoy this course on increasing feelings of safety for dogs. Safety learning is an important part of a three-pronged approach to adaptive behaviour rather than increased anxiety.

And if you want more, you can always sign up to the Lighten Up mailing list for occasional offers or ideas