Many dog owners, have noted the syrupy effect that “puppy dog eyes” have on us. Our hearts melt, years of hardened defenses fall away, and we trip over ourselves to fulfill whatever requests we think our doggos are making.
Turns out, puppy dog eyes hold that power over us because hoomans associate more pronounced, expressive inner eyebrows with babies. A study from the Proceedings of the National Academy of Sciences of the USA (July 16, 2019) found that when meeting a person’s gaze, dogs often raise their inner eyebrow muscle upwards and inwards to make their eyes look larger and more appealing.
The researchers wrote: “Interestingly, this movement… resembles an expression humans produce when sad, so its production in dogs may trigger a nurturing response.”
This muscle, called the levator anguli oculi medialis, is almost entirely absent in gray wolves. Another muscle called the levator anguli oculi lateralis, runs along the eye’s outer edge and exposes more of the white of the eye, making domestic dogs appear even more human-like. Wolves don't use it much at all.
Apparently, that’s the kind of look hoomans prefer, so dogs decided to make themselves more like that, over 30,000 years of evolution. To get even closer to us. Awww…