Genetics vs Environment in Reactivity
Reactivity is rarely caused by just one thing. In most dogs, it is shaped by a combination of genetics, early life experiences, learning, stress, and sometimes pain. Modern behavioural science emphasises that behaviour emerges from the interaction between biological predisposition and environmental input, rather than either factor alone (van Rooy et al., 2014).
What genetics can influence
Some dogs are born more sensitive, more alert, or quicker to react to change. These traits are part of temperament, which has a measurable heritable component in dogs.
Genetic influences can affect how easily a dog becomes aroused, how quickly they recover from stress, and how strongly they respond to novel or unpredictable stimuli. These differences are not inherently problematic, but they can make some dogs more vulnerable to developing reactive patterns in challenging environments.
Breed tendencies can also play a role. Dogs bred for guarding, herding, or high responsiveness to movement may be more likely to notice and react to environmental changes. These traits can be strengths in the right context but may contribute to reactivity in busy or unpredictable environments.
What environment can influence
Early experiences matter a great deal. The socialisation period, particularly in the first few weeks of life, is critical for shaping how a dog responds to novelty and potential threats (Appleby et al., 2002).
Positive, gradual exposure to different environments can support resilience, while overwhelming or negative experiences can increase sensitivity. A lack of appropriate exposure can also lead to heightened responses later, as unfamiliar stimuli are more likely to be perceived as threatening.
Pain and illness can further influence behaviour. A dog experiencing discomfort may have a lower tolerance for stress and may react more strongly to situations they would otherwise handle. Veterinary behavioural research consistently emphasises the importance of ruling out medical factors in behaviour change (Mills et al., 2020). This could be due to injury, illness or allergens ecperienced in the environemnt.
Why it matters to know the difference
Owners often look for a single cause, but reactivity is usually the result of multiple interacting factors.
Understanding this helps reduce misplaced blame and supports more realistic expectations. Instead of focusing on what caused the behaviour in the past, it becomes more productive to focus on what will help your dog in the present. This can also help some owners who may feel guilt around how their dog perceives and interacts with the world.
What this means for training
If genetics play a role, the goal is not to override them but to work with them. That means adjusting expectations, managing the environment, and building skills gradually within youor dog’s comfort zone. This can also involve incorporating species and breed-specific outlets for your dog.
Progress may not be linear. Some dogs will improve quickly, while others require ongoing management and slower, more structured support.
Reactive Dog Photography
This perspective is especially important for owners who feel discouraged. A reactive dog is not a failed dog, and it is not a reflection of poor ownership.
A well-designed, low-pressure photo session can support your dog by providing a controlled, predictable environment where they are not pushed beyond their limits.
FAQs
Are reactive dogs born that way?
Temperament plays a role, but experience is also a major factor.
Can environment cause reactivity?
Yes, particularly through early experiences and repeated stress.
Can a dog outgrow reactivity?
Some dogs improve significantly, but many benefit from ongoing support and management.
References
Appleby, D.L. et al. (2002) Veterinary Record, 150, pp. 434–438.
Mills, D.S. et al. (2020) Animals, 10, p. 318.
van Rooy, D. et al. (2014) Canine Genetics and Epidemiology, 1, p. 7.