Anxiety, fearfulness, and personality-related disorders are quite common in humans. According to data published by the U.S. Centers for Disease Control (CDC), by age 40, about 50 percent of the population will have, or will have had at some time previously in their lifetime, some symptoms of psychological problems which are related to mood or anxiety difficulties. Most of these are not severe enough to require clinical intervention, although when symptoms are active, they can be disturbing and affect family and social relationships. A new study coming out of Finland suggests that the prevalence of problem behaviors associated with things like fearfulness may be equally likely when it comes to dogs.
This new research comes from the laboratory of Hannes Lohi, a geneticist at the University of Helsinki. A team of researchers headed by Milla Salonen surveyed 13,715 Finnish dog owners (which would be nearly 2 percent of the total population of pet dogs in Finland). Owners were asked to rate their dogs' behavior on seven different anxiety-related traits: noise sensitivity (for example, reactions to thunder or fireworks), general fear, fear of heights and surfaces (like reflective tiles), hyperactivity or impulsiveness, compulsive behaviors (like relentless chewing or tail-chasing), aggression, and separation anxiety.
As in the case of humans, the prevalence of these problems is quite large, and only 28 percent of all of the dogs have never shown any problematic behavior in any of these areas over their lifespan.
A fearful reaction to noises was the most common across the total sample, affecting 32 percent of the dogs. About 17 percent of the pet dogs in the sample were fearful of other dogs, 15 percent were afraid of strangers, and 11 percent were frightened by new situations.
There were some age-related trends, with one surprise being that noise sensitivity (especially fear of thunder) tended to increase with age. On the other hand, hyperactivity and impulsivity, the sort of thing which leads to dogs careening around the house in a frenzy or tearing up furniture, steadily decreases with age.
There were also sex-related differences, with male dogs more likely to demonstrate aggression, and female dogs more likely to show fearful behaviors.
However, one of the most interesting sets of findings has to do with breed-related differences since when these occur, they are most likely to be due to inherited genetic predisposition. In this particular sample, there were 264 breeds represented. To make reliable comparisons, the researchers limited themselves to the 14 breeds which had 200 or more dogs represented in the survey. Some of these breeds (like the Lagotto Romagnolo, a large, fuzzy retriever native to Italy) are not very familiar outside of their home country or in Finland, so I will stick with the more commonly recognized and widespread breeds.
Fear of thunder was most marked in Wheaten Terriers, Rough Collies, and Staffordshire Bull Terriers. The lowest level of noise sensitivity was found in the Labrador Retriever, with the Bernese Mountain Dog and German Shepherd Dog also being not very reactive to noises. These differences are quite large since, for instance, the Wheaten Terrier is more than three times as fearful as the Labrador Retriever.
Fear of strangers is very common in Shetland Sheepdogs, Miniature Schnauzers, and Bernese Mountain Dogs and lowest in Border Collies, Wheaten Terriers, and Staffordshire Bull Terriers.
Hyperactive and impulsive behaviors were found to be quite frequent in German Shepherd Dogs, Staffordshire Bull Terriers, and Border Collies, while they were much less frequent in Wheaten Terriers, Miniature Schnauzers, and Rough Collies.
Aggression toward strangers was quite high in Miniature Schnauzers, German Shepherd Dogs, and Border Collies. It was lowest in Labrador Retrievers and Smooth Collies. Also, I must admit, to my surprise, it was relatively low in the Staffordshire Bull Terrier.
Some of these problems are tightly associated with each other (the technical term for this is "comorbidity"). The most important finding seems to be that dogs that are fearful are more than three times more likely to be aggressive. Similarly, dogs that are hyperactive and impulsive are more than three times more likely to show symptoms of separation anxiety.
Looking across the breed breakdowns for the various behavior problems measured in this study, it turns out that the breed that is least likely to show high levels of anxiety-related behaviors turns out to be the Labrador Retriever. This may well account for part of the enduring popularity of this breed as a pet all over the world.
The reason why breed-specific differences are scientifically important is that breeds differ from each other on the basis of their genetic makeup. When you find a psychological characteristic that differs among breeds, that is usually a sign that you are looking at a psychological characteristic predominantly determined by genetic and inheritable factors.
Professor Lohi summarizes this study by saying, "Our findings indicate that unwanted behavior seems to be inherited, which means that, through careful breeding that relies on suitable behavior indicators, the prevalence of such behavior traits could be decreased. This would improve the quality of life of not only the dogs but their owners too."
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Salonen, M., Sulkama, S., Mikkola, S., Puurunen, J., Hakanen, E., Tiira, K., Araujo, C., Lohi, H. (2020) Prevalence, comorbidity, and breed differences in canine anxiety in 13,700 Finnish pet dogs. Scientific Reports. doi: 10.1038/s41598-020-59837-z