Wednesday, 13 March 2013

Do Dogs Find Their Owners Presence Supportive When a Threatening Stranger Comes Near?

How does your dog compare to a toddler? Recent animal research is comparing the abilities of dogs with young humans. A brand new study by Márta Gácsi et al in Hungary investigates whether dogs have the same response as infants to a test called the Strange Situation.

An Asian girl with a poodle in her arms, outside in the gardenIn humans, attachment theory explains how children need to develop a strong attachment to at least one caregiver. If they don’t, their social and emotional development will be disrupted. As infants begin to crawl, the caregiver is a ‘secure base’ from which to explore. 

Mary Ainsworth developed the Strange Situation as a way of investigating attachment. This is a standardized procedure in which the infant is in a room with their caregiver when a stranger comes in. Following a strict protocol, the baby is left alone with the stranger, then comforted by the caregiver, left all alone, then joined by the stranger again. An infant that is securely attached will be upset when the caregiver leaves the room, but is happy to see them return and easily soothed. 

Attempts to replicate the Strange Situation with dogs have led to mixed results, probably because a well-socialized dog is happy to see a friendly stranger. So Gácsi et al designed this study to include a threatening approach from a stranger, to make it more difficult for the dog. 

They measured the dog’s physiological response in terms of heart rate (HR) and heart rate variability (HRV), as HRV can be an indicator of stress even when HR is unchanged. To do this, they had to shave three small patches of the dog’s fur and attach electrodes.

Thirty-two medium or large pet dogs took part in the experiment at Eötvös Loránd University in Budapest. After the heart rate monitor was fitted in a waiting room, the dog and their owner were left alone in the experimental room for ten minutes. This gave the dog time to explore and get used to the surroundings. The room was fitted with video cameras so that the dog’s behaviour could be recorded.

The experiment itself had two conditions that were counter-balanced. In other words, half the dogs first experienced the threatening approach from the stranger when they were with their owners, and later experienced it without their owners. The other half of the dogs first experienced the threatening approach without their owners, and the second time they had their owner present. 

The stranger was a female experimenter who approached slowly, staring at the dog, as this is something dogs find threatening. However, because movement can affect HR, if the dog moved around or barked she stopped and waited until the dog settled down again. The data from the time when the dog was moving was discarded. At the very end, the stranger had a friendly interaction with the dog, so as to finish on a positive note.

The dogs’ heart rate increased during the threatening approach, and it increased most when the owner was absent. Heart rate variability, also a sign of stress, increased most when the owner was absent and the stranger was not approaching.

A man with his grand-daughter, little dog and cat, seated outside
Of course, some dogs react more strongly to separation from their owner or to the sight of strangers. So Gácsi also did an analysis comparing reactive to non-reactive dogs. Dogs were defined as reactive to separation if they whined or barked while the owner was gone. For these dogs, HRV increased during separation, but less so when the stranger approached. 

Dogs were defined as reactive to the threatening approach if they growled or barked at the stranger. For these dogs, HR increased significantly when they saw the stranger, but less so if their owner was present, or if they had previously seen the stranger when the owner was present. Interestingly, the non-reactive dogs actually had no overall HR increase during the threatening approach. It turns out that some of these dogs had a slight increase (stress) and some had a slight decrease in HR (because they were interested in the stranger), and these balanced each other out.

These results show some similarity to the behaviour of infants during the Strange Situation. During the threatening approach, the increase in dogs’ heart rate was not as great if the owner was with them. In the reactive dogs, there was a protective effect if they first met the stranger when the owner was present; this made them less stressed when subsequently meeting the stranger without the owner present (though still not at baseline).

The presence of the owner had a ‘secure base’ effect, similar to that of a caregiver with an infant. The authors say “our results contribute to earlier findings that dogs and humans provide social support for each other in stressful situations.”

This relates to studies of social referencing. Infants look to their caregiver for information about a new object, and alter their behaviour accordingly (i.e. approach or avoid). Studies of dogs with a strange object have found similar results

One drawback to the current study is that, because the measurements were affected by movement, if the dog moved the stranger had to pause her approach and the data during that time could not be used. So it was not a natural approach, and the total time the dog was in the presence of the stranger varied depending on the dog’s response. Nonetheless, it shows that the presence of the owner provides some security for the dog if they are threatened by an approaching stranger.

The study also shows there are individual differences in how dogs respond to separation from their owner and to a threatening stranger. Some of the dogs were interested in the stranger despite her threatening manner of approach, whereas others reacted by growling and barking. How does your dog respond to strangers?

Reference
Gácsi, M., Maros, K., Sernkvist, S., Faragó, T., & Miklósi, �. (2013). Human Analogue Safe Haven Effect of the Owner: Behavioural and Heart Rate Response to Stressful Social Stimuli in Dogs PLoS ONE, 8 (3) DOI: 10.1371/journal.pone.0058475

4 comments:

  1. Dog/human co-evolution: my favorite topic of study... as usual, I'd like to see a study on the reciprocal reaction of the human - i.e., does a human find his/her dog's presence supportive when a threatening stranger comes near? I don't think the results would be surprising.

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  2. Thanks Glenn. It's one of my favourite topics too. I like your idea for a study!

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  3. Dogs are body language experts, I believe they would know the difference between an actual threat and one pretending to be a threat, but interesting none the less.

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  4. I find the Strange Situation experiment to be easily explainable in infants. When the caregiver responds to the infants every need and has a warm sense of being, the infant is going to be unsettled when the caregivers leave the infants presence. I believe an important factor in the study of dogs and secure attachment is the upbringing of the dog. Has the dog been with their owner since infancy? And if not how many owners has the dog had before? Dogs who have been with their owner since birth or infancy have a higher attachment to their owner. They do indeed make each other feel safe and this could possibly cause anxiety towards strangers. However, if the dog has had many owners before, it is quite possible they would be more comfortable around strangers. It also depends on the owner. Do they take their dogs out for frequent walks around other people? Do they take their dog to the dog park? My dog was sick in it's early life. He belonged to a shelter who gave up on him and were going to euthanize him. My mother however, took him in and nurtured him back to health. Ever since then my dog has been extremely attached to my mother and very sensitive to the presence of strangers. After ten years, he still barks at me when I walk through the door. This is a very interesting topic.

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