Trying to figure out what makes that adorable pup decide to either cover you in kisses or bark and growl is way more complex than you might think.
From the way you look to the sound of your voice — and a couple surprise things in between — there's a ton that goes into how your dog reacts towards you and to a complete stranger. And just like first impressions are huge for us humans, the same goes for dogs.
It turns out, a dog has likely made an opinion about you the first time it saw you.
When humans see a new face for the first time, we automatically look at the right side first. This is because "the right side of our faces can express emotions more accurately and more intensely than the left, including anger." This is called left gaze bias and dogs do it too. Researchers from the University of Lincoln have shown that dogs also display left gaze bias, but only when looking at human faces.
How you interact with other people
While you've been casually chatting it up with her owner, she's been watching the many behavioral cues bouncing back and forth between the two of you. One thing she's likely taking note of is your attitude towards her owner.
A team of researchers from Kyoto University in Japan conducted a study to determine how dogs would react to people who were either helpful or unhelpful to their owners. The researchers equipped dog owners with a clear container that held a roll of tape inside and sent in actors to either help open the container, be unhelpful, or remain indifferent. Afterwards, the dogs were offered treats by the actors, and the team found that the dogs avoided taking food from the unhelpful actors.
According to the study, "this suggests that dogs evaluate people by watching their interactions with the owner and that they avoid people who behave negatively to the owner." In the end, the dogs used the information in front of them to form an opinion on which people to take the treat from and which ones deserved the cold shoulder.
This works the other way around too, meaning dogs also watch how their owner reacts to strangers. This is called social referencing and is something humans do straight from the womb. When encountered with a situation, children will look back and forth from the person in question and their caregiver to gauge the emotional and behavioral response to help guide their own actions. According to an article published by Psychology Today, dogs operate the same way, "...dogs, like human infants, look to the significant humans in their life to help them interpret situations which might be ambiguous or problematic." So if you clearly don't like someone, your dog probably won't either.
Taking it one step further, dogs are also capable of distinguishing between more human emotions than just good and bad. Thanks to a study done by the School of Life Sciences at the University of Lincoln, there is now evidence that dogs "have the ability to integrate two different sources of sensory information into a coherent perception of emotion in both humans and dogs." What this means is that dogs are able to combine your facial expression and the sounds you make to assess how they should respond.
Your body language
Other than what dogs are able to observe from the sidelines, the way they are approached by a stranger also plays a big role in their decision to maul you with kisses or not.
A group of researchers from Eotvos University conducted a study to see how dogs would react when approached by strangers in both a friendly and threatening nature (with the dogs owner out of sight, so as not to mess with their social referencing abilities). The researchers discovered that, "the majority of dogs showed cues of tolerant, friendly behaviors upon Friendly approach by the Stranger, many of them gave various signs of avoidance or aggressiveness when the Stranger approached them threateningly."
The tone of your voice
You can make good with their owner and approach them in a non-threatening way, but there are still a few other factors that can influence a dog's opinion. Like the tone of your voice and the way you smell.
A new study in the Current Biology journal has found that dogs possess "brain systems that are devoted to making sense of vocal sounds, the same systems humans use to make sense of human speech." The part of the brain they're referring to doesn't put together words or sentences, but is responsible for detecting subtle changes in pitch, tone and identifying distress signals in your speech patterns.
The way you smell
When it comes to smells, familiar is best.
Another study by Emory University found that the section of a dog's brain (the caudate) that processes positive emotions only lights up when faced with a familiar human's scent, even if that person isn't the dogs primary caregiver. So, if your friends dog doesn't take an immediate liking to you the first time you visit, they will once they establish your scent as familiar.
Whether the dog is left or right pawed
While the look on your face, tone of your voice, and way you approach a dog are all things you can manipulate to your benefit, there are others you simply cannot control, like whether they are left-pawed or right-pawed.
We kid you not. There's actual evidence that suggests dogs who prefer to use their left paw are "more likely to show aggression towards strangers than right-pawed ones" according to a study by the University of Adelaide. This is also true in humans since the left hand (or paw) is controlled by the right side of the brain, which is associated with negative memory and emotion. Moral of the story: watch out for the lefties!
Your dog's history
More things out of your control: Whether the dog came from a shelter, breeder or a pet store.
A study published in Applied Animal Behavior Science found that dogs from pet stores or rescue groups were more aggressive than those purchased from breeders. This may be due to something called stranger phobia which is an extreme negative reaction to even non-threatening strangers, probably due to past traumas. While this may seem alarming, it is something that can be corrected with a little therapy and a lot of love.
One group from Henderson State University tested this theory on three shelter dogs and were pleased to find that "results suggest that our therapeutic technique is effective in treating stranger phobic reactions in shelter dogs."
While researchers did find a correlation between shelter dogs and increased aggression, the one thing they did not find: one based on breed. According to their study, "it would be inappropriate to make assumptions about an individual animal's risk of aggression to people based on characteristics such as breed." Pit bulls everywhere just breathed a sigh of relief!
So what did we learn from all this? That dogs are way smarter than we thought and are actually freakishly in-tune with our body language and emotions (maybe even more so than we are). So the next time your dog growls at a stranger or jump all over one affectionately, you should probably pay attention. Now if only you could bring your dog on all your first dates...