Just like humans, it's important for animals to develop relationships with their own kind. However, when it comes to domesticated animals, relationships can go in a different direction. Researchers have found that pet owners oftentimes develop strong bonds with their pets similar to that of a parent and their infant child.

This bond is known as the "secure base effect." It's normally a bond found in infant children as they try to understand the world around them. Children often gravitate towards their caregiver, using them as a base for interacting with their environment. The effect influences their daily lives and can also affect their performance in cognitive testing.

According to a new study, dogs become attached to their caregivers in much the same way that a child using the secure base effect. Researchers at Vetmeduni's Messerli Research Institute of the University of Veterinary Medicine, Vienna, performed two experiments on dogs' behavior.

In the first experiment, they tested 20 dogs' reactions during three different settings: having an absent owner, a silent owner with a blindfold on, and an encouraging owner. The dogs had to manipulate toys in order to get a treat inside. The researchers found that it was only the owner's presence that affected how the dog reacted. If the owner wasn't in the room, the dogs spent less time trying to retrieve the treat from inside the toys. They also tested for separation anxiety in two pre-experiment absence tests — they found that separation anxiety had no effect on the dogs' performance in the experiments.

"In this case, dogs that experienced strong separation distress would have been expected to manipulate shorter than dogs that were not distressed by the owners absence," the authors wrote. "However, since the dogs' duration of manipulation was not negatively correlated with their individual separation-related behavior score, we showed that the owners absence did not affect the dogs differently."

Because of this, they concluded that the only reason the dogs didn't spend as much time with the toys was because the owner wasn't there as a secure base.

Following up on this experiment, the researchers then tested whether the dogs would compete the tasks when their owner was replaced with a stranger. The dogs showed no interest in the strangers, and, furthermore, didn't show much interest in the food when the stranger was there or not.

"The fact that the presence of an unfamiliar human did not significantly increase the duration of manipulation in the dogs compared to when they were alone with the experimenter provides evidence for a secure base effect in dogs that's specific for the owner, and therefore, comparable to the one found in infant-caregiver relationships," they wrote.

This study provides the first evidence comparing the similarities of the secure base effect between dog-owner and child-caregiver. In a 2003 study based on the Ainsworth "Strange Situation" Assessment, 38 dogs and their owners were put into an unfamiliar room and introduced to a stranger. The dogs were subjected to four periods of separation in which the owners would leave and then come back. The stranger also left during one period, leaving the dogs completely alone.

The researchers found evidence pointing to a secure base effect from the beginning, when the dogs were more inclined to play with the stranger while the owner was present. However, there was more evidence pointing to attachment, because the dogs would scratch, jump at the door, or stare at the door or the owner's chair when they weren't present. They were also much more enthusiastic, and greeted their owners for a longer duration after the separation, than they did for the strangers. Finally, when the dogs were left completely alone, they were more inclined to make contact with their owner's clothing and sat closer to their chair, rather than the stranger's.

Having this relationship could contribute to the reasons why the American Heart Association (AHA) said pets can reduce the risk of heart disease.

"Pet ownership is an important nonhuman form of social support and may provide cardioprotective benefits in patients with established cardiovascular disease," a statement said.

The AHA said that studies have shown having a pet can increase physical activity, boost favorable lipid profiles, lower systemic blood pressure, improve autonomic tone, diminish sympathetic responses to stress, and improve survival after acute coronary syndrome.

Sources:

Horn L, Huber L, Range F. The Importance of the Secure Base Effect for Domestic Dogs — Evidence from a Manipulative Problem-Solving Task. PLOS One. 2013.

Prato-Previde E, Custance D, Spiezio C, et al. Is the Dog-Human Relationship an Attachment Bond? An Observational Study Using Ainsworth's Strange Situation. Behaviour. 2003.