Can your Dog smell your fear?

Dog with nose against red rose

Source: University of Naples, Italy -Dog congitive study

Researchers at the University of Naples recently studied whether puppies and adult dogs differ in their abilities to detect human emotions via scent alone. The results solidified parts of what dog trainers use regularly and showed the difference between puppy and adult dog development of anxiety based reactions.

White Samoyed puppy sitting in grass behind a stuffed goose toy

The study

The researchers collected the underarm perspiration of people who were experiencing either fear/anxiety or happiness. The reactions of two sets of dogs were tested: puppies less than six months of age and adult dogs more than 1 year of age. All of the dogs lived in homes and participated in the study with their owner. A group of 61 puppies and 80 adult dogs completed the study. As in the earlier work, both the owner and the person acting as the unfamiliar human were blinded to the dog/puppy’s group assignment (fear, happiness, or control).


  1. The Scent of Fear: Both puppies and adult dogs demonstrated signs of stress in response to being exposed to the odor of human fear. A common behavior in all of the dogs was to seek out the proximity of their owner. This response has been described in other studies and provides additional evidence for owners acting as a safe and secure place for their dogs during stressful situations.
  2. The Scent of Happiness: The behaviors of the adult dogs when exposed to “happy sweat” were similar to those reported in the earlier study. Adult dogs were more likely to approach a stranger and somewhat less likely to move towards the door when compared with the control group and the fear group. Conversely, the behaviors of puppies when they were exposed to “happy sweat” did not differ from their behaviour when in the control group. These results suggest that adult dogs, but not puppies, are sensitive to odours associated with human happiness and relaxation.
  3. Inability to Detect or Lack of Behavioral Response? The lack of a distinction between puppies’ behaviours during the control (no scent emotion) and the happiness scent condition suggests that either puppies do not possess an ability to detect the odour of happiness OR that they detect it, but have not yet developed a behavioural response to it. The authors make the point that the study design did not allow them to distinguish between these two possibilities.
  4. Fear Response – Innate vs. Biologically Prepared: The fact that puppies reacted to fear but not to happiness suggests that either puppies are born with an ability to detect and respond to the smell of fear (i.e. it is innate) or they are born biologically prepared for this response. Preparedness refers to puppies possessing the ability to rapidly learn a response shortly after birth.
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The researchers found that responses to fear odors were pronounced and relatively consistent in both adults and puppies. The major difference between the two groups was that adult dogs showed consistent positive responses to the happiness odors, while puppies’ responses to the scent of happiness did not differ significantly from their responses to no scent present (i.e. the control condition). These results suggest that young dogs must learn this association during development as opposed to fear which appears to be hard-wired in them.

What it means

We know that puppies in particular need good socialization to become balanced later in life and this study showed that exposing them to fearful or stressful situations continuously isn’t desirable.

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