FEATURE | FACTORS ASSOCIATED WITH AGGRESSION
What Factors are Associated with Aggression ?
Study surveys 9,000 Finnish dogs to examine probable causes for aggressive behavior
By Kristina Spaulding , Ph . D , CAAB , and Irith Bloom , CPDT-KSA , CDBC , KPA CTP , VSPDT , CBATI
In this issue , we ’ ll be discussing a recent article by Salla Mikkola , a doctoral candidate from the University of Helsinki , and colleagues on factors associated with aggression toward people in dogs . Several studies have already been conducted examining what factors are associated with canine aggression towards people . Given how science works , however , it ’ s important that data be gathered from multiple different populations of dogs , using a variety of methods , for us to construct a complete picture . Previous studies have indicated that dogs that are male , older , and fearful are more likely to display aggressive behavior . Some studies have also found that families with more household members , a dog being an only dog , and living in a rural area are associated with increased aggression . The size of the dogs and their spay / neuter status have shown inconsistent results , but some studies have found that small dogs and surgically sterilized dogs are more likely to show aggression .
There is another important thing to note : All of these studies are survey based and the dogs in the studies were not randomly placed into one condition or another . The researchers themselves did not randomly determine if a dog was going to be spayed or neutered . That means that we cannot say that spay / neuter or living in a rural area , for example , caused aggression . We can only say that they are associated with each other . Without a study in which different test conditions are randomly assigned and the researchers measure what happens in each condition , it ’ s impossible to say anything about causation . In this case , it ’ s possible that spaying or neutering increased the likelihood or severity of aggression . It ’ s also possible that dogs that have certain characteristics are more likely to be spayed or neutered . That means we must not jump to conclusions about the directionality of the relationship – in other words , what is causing what – based on survey data .
The rates of aggression seen in these studies also vary widely . One thing that does seem clear , though , is that aggression toward strangers ( out-group members ) is more common than aggression toward family members ( ingroup members ). Rates of aggression toward family members range from 3 to 16 percent , while rates of aggression toward strangers range from 5 to 45 percent .
The particular study we are looking at today was based on survey data from more than 9,000 Finnish dogs . The data was gathered between 2015 and 2018 . In this study , aggression was defined as growling , biting , or snapping . The study only included dogs that had high levels of aggression ( bit or snapped ‘ sometimes ’ or growled ‘ often ’) and dogs with no aggression . They limited the data in this way for statistical reasons . The statistical analysis they were using required a binary variable , in this case ‘ high aggression ’ or ‘ no aggression ’. Therefore , it ’ s most accurate to say that this study examined factors associated with higher levels of aggression toward people , not just any aggression or low levels of aggression .
The APDT Chronicle of the Dog | Winter 2021 35