It’s clear that dogs excel at comprehending our emotions and behaviors. But how deeply does this understanding go, and what signals do they pick up on?

The dogs who live alongside us are often more astute in their observations than we might think. In many ways, they act like anthropologists, dedicating time to study us and uncovering connections between our actions that even we may be unaware of.

At home, you might notice their ability to differentiate between standing up to leave and simply heading to the fridge.

Research has shown that dogs are capable of reading stress, discerning detecting fear, and even identifying the presence of disease in us. While their extraordinary sense of smell plays a role, their understanding goes beyond physical cues, acknowledging our emotional and physiological states.

When interpreting emotions, humans typically focus on the face—and dogs do the same. They are adept at reading our facial expressions.

Studies on how dogs perceive human emotions indicate that they can differentiate between neutral, angry, and happy expressions. Interestingly, they can also associate vocalizations with the corresponding emotional tone of these expressions.

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Dogs can interpret a person’s expression when approaching an object (such as joy or disgust) to gauge whether they should get closer themselves. They can even process images of just the upper half of a face, showing that they can understand emotions even when part of the face is obscured, like by a mask.

Moreover, they recognize our voices and can differentiate the genders of unfamiliar voices.

Recent studies confirmed that dogs are perceptive to fear, able to identify shirts worn by individuals who watched a scary movie from those worn by those who were watching something neutral.

They can also recognize changes in our body language that indicate fear and stress. One study revealed a correlation between human testosterone levels (influenced by a sports team’s performance) and a dog’s cortisol levels, indicating their sensitivity to our emotional states.

Having spent countless hours observing us from their cozy spots in the living room, dogs have developed an acute awareness of our intentions and feelings.

For instance, research found that dogs can discern between intentional actions (like deliberately placing an object out of reach) and unintentional incidents (like unintentionally dropping something).

Studies confirm that even when we’re out of sight or simply turning away, they are aware of when we sneak a snack forbidden from their reach. They also notice when our attention is diverted, like when we’re glued to a book or staring at a screen, indicating a window for them to grab that tempting treat.

More broadly, they’re adept at assessing whether individuals possess knowledge about hidden food sources.

Finally, and most impressively, dogs have a remarkable ability to detect illness. Initial reports of pet dogs identifying melanoma by scratching their owners’ skin have led to research where dogs have been trained to identify various cancers through scent, as well as monitoring blood sugar levels and even recognizing glycation.

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