Puppy Dog Eyes
Ahh. So cute. We've all seen those "puppy dog eyes" and usually with the same reaction. But why do dogs give us this endearing gaze?
Studies have shown that eye contact is an important aspect of human bonding and is associated with increased levels of oxytocin, the feel good hormone.
In a study documented in Live Science, researchers found elevated levels of oxytocin in both humans and dogs after they spent some time just gazing at each other.
It has been well documented that dogs as we know them evolved from more social wolves hanging around human encampments and scrounging for food.
So have dogs actually developed this trait as a way of weaseling more food from us?
Since dogs do not generally use eye contact in intra-species communication, the same study surmised that this endearing trait developed strictly to communicate with humans.
Indeed, in a study documented in Current Biology, a group of wolves that had been socialized to humans were unable to locate food treats pointed out by the humans by either touching or pointing to the same degree of success as dogs. In a second part of the same study the animals were given an insolvable task such as getting to food in a jar. The wolves in this case would eventually give up and leave, however the dogs, presented with the same dilemma, tended to turn to the humans for help, engaging eye contact.
This behavioral development actually led to a physical evolutionary development in the facial muscles of dogs. The excellent PBS program Nova looked into this and documented studies showing that wolves lack two sets of facial muscles required to manipulate the facial expression we know as puppy dog eyes. One set of these muscles is used to lift the eyebrows up, while the other, pulls to the outside resulting in the wide, expressive eyes that remind us of human babies, or a person on the verge of tears, generally resulting in an emotive response from the subject human.
As a sort of "missing link" in this evolutionary development, Nova reported that one species, the Siberian Husky, has only one set of these muscles, the ones used to pull the eyebrows up. This is because Siberian Husky's are more like their distant relative the wolves and have only developed one set of these muscles. So are our four legged friends master manipulators or just making use of an evolutionary response taught by eliciting a beneficial response from us. Either way those puppy dog eyes seem to benefit both species.