Why is My Dog Still Barking and Lunging? The Role of Fear Incubation in Anxiety-Based Behavior Problems

by Robin Foster, PhD, CAAB
Certified Applied Animal Behaviorist

Canine behavior problems rooted in fear and anxiety are some of the most common complaints presented to veterinarians, applied animal behaviorists, and trainers.  Anxiety-based problems are difficult to treat, and in both people and animals there can be an unexpected increase in fear in the absence of any negative experiences. 

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Behavior modification to treat anxiety typically involves desensitization; the dog is exposed to the feared stimulus without anything bad happening and without triggering fight or flight responses, such as barking, lunging, or balking.  In theory repeated exposure--especially when paired with a pleasurable event like a treat (counter-conditioning)--should lead to a decrease and ultimate extinction of the fear and reactivity.  But in reality fear-based behavior problems are notoriously resistant to extinction and in some cases may even get worse. For example, suppose your dog becomes alert and shows signs of stress when he spots another dog on the other side of the street, and nothing bad happens.  In theory this neutral (or even positive) experience should reduce your dog’s fear and anxiety, but maybe it persists or gets worse.  Why?! 

There are many possible reasons, but one that is rarely discussed in dog training circles is a well-known phenomenon called incubation.  In the late 1960s European personality psychologist Hans Eysenck introduced the concept of incubation.  He used this term because in both humans and animals fear often seems to incubate, or intensify, in the absence of any experience.  Several studies published over the last half-century have confirmed that four key factors account for fear incubation and resistance to extinction.

1. How strong was the initial bad experience that created the fear in the past?  If the initial trauma was severe, fear will be more resistant to treatment.  Getting hit by a car, beaten by an owner, or viciously attacked by another dog are pretty intense bad experiences.  This is not a particularly surprising finding, but in practice we rarely know the individual history well enough to identify the cause of the fear and anxiety.
   
   
2. What is the animal's temperament?  Individuals with neurotic/introverted temperaments are more vulnerable to both fear conditioning and incubation compared to laid-back/extroverted temperaments.
   
   
3. How strong is the stimulus that the individual is reacting to in the moment?  When the stimulus in the moment is intense the fear is more likely to persist and may even get worse.  For example a close, large, energetic dog is more intense than a distant, small, quiet dog.    
   
   
4. How long is the duration of exposure to the stimulus in the moment?  A brief exposure with rapid retreat can slow the progress of desensitization and is one of the most reliable predictors of fear incubation.  Long duration exposures are better.

The first two factors are nearly impossible to control and behaviorists are often trying to manage the consequences of their effects on fear and reactivity. The third and fourth factors come into play during behavior modification and should be taken into consideration when using exposure methods to treat fear and anxiety.

Recent studies of incubation have focused on the brain and have found a link between an individual’s vulnerability to incubation and low levels of a substance called brain-derived neurotrophic factor (BDNF).  One study showed that fear was extinguished equally quickly in animals with low and normal levels of BDNF, but that fear was more likely to reappear in animals with low BDNF after just one bad experience following fear extinction (this is called renewal).

There are two take-home points for behaviorists and trainers.  First, owners should be made aware that the treatment for fear and anxiety will generally take longer and may be vulnerable to relapse in animals with a neurotic/introverted temperament or a history of trauma.   Second, behavior modification recommendations should emphasize long exposures to weak triggers.  In my experience many failed desensitization efforts are a direct result of violation of these two conditions. For example, letting another dog approach and greet a fearful dog is too intense!  Quick retreats at the first sight of an approaching dog is too brief!   Letting your dog watch another dog from a distance and for a long time (until he loses interest is best) will produce the most effective results in most cases.  I have used the example of dog-dog reactivity, but the same principles apply to any fear-based behavior issue.

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References

Eysenck H. 1968. A theory of the incubation of anxiety/fear responses. Behaviour Research and Therapy 6(3):309-321.

Pickens C, Theberge F. 2014. Blockade of CB1 receptors prevents retention of extinction but does not increase low preincubated conditioned fear in the fear incubation procedure. Behavioural Pharmacology.  25(1):23-31.