Humans are hardwired to read facial expressions because they’re integral to social communication in our species. Our brains even scan the mugs of other species to discern their mood and intent. And most people who have interacted with dogs or cats can agree they too have expressive faces, to one degree or another.
Technically, most mammalian species do. This is a unique function of the flexible skin and intricate musculature overlying their skulls. Charles Darwin was among the first to speculate about the nature of these movements with his 1872 book, The Expression of the Emotions in Man and Animals.
We tend to perceive cats as inscrutable and willfully uncommunicative. Dogs, on the other hand, are viewed as open and unabashed about telegraphing their feelings. These intuitions are so strong that they are in turn used to describe human demeanors. A person who appears mysteriously self-satisfied is said to resemble “the cat that caught the canary.” Meanwhile, someone with a sad or beseeching expression is making “puppy dog eyes.” But are these stereotypes accurate?
Research on the subject paints a complicated picture.
It’s true that cats are likely relatively hard to read. They share a much briefer evolutionary history with us compared to dogs — as much as 24,000 years shorter — so we are accordingly less proficient at decoding them. But as it turns out, they produce a suite of facial expressions just as complex as those evoked by their canine counterparts. And while we do seem to read dogs more accurately, studies have shown that we’re not nearly as adept at discerning the true meaning of their expressions as we think we are.