It's no secret even to the layperson with a basic understanding of body language that identifying people's emotions usually comes through their facial expressions, like, for example, how they smile, or how they look at us with their eyes.

As it turns out, research has added even more depth to this discussion by alerting us to how someone's voice -- specifically tone and pitch -- may clue us into what's going on inside someone's head.

Lets bring in an expert to expound further on all four areas: smile, eyes, voice, and pitch. Dr. Donna Van Natten, the Body Language Dr, wrote the do's and don'ts of nonverbal communication in her provocative new book, Image Scrimmage.

Watch the Smile

In a recent interview I conducted with Van Natten, while smiling seems intuitive and conventional wisdom asserts we should smile for a positive impression, Van Natten points out that people smile differently, and depending on how we do it, it can either help or hurt us.

Here's Van Natten:

Smiling is an activity which involves the whole face, and even the body. Do our eyes sparkle as we smile? Are we making eye contact? What about our facial muscles...tense? Relaxed? Is our body open or closed? Duchenne's research on facial and eye muscles helped humans read an authentic versus fake smile. The eye muscles are quite involved. You know -- those crow's feet on the side of our eyes and those crinkle/wrinkles we make. People hold smiles to mean different things. A flash when we enter a room may indicate familiarity and welcoming of a known friend. A longer smile may infer discomfort -- a frozen smile when, at the same time, the eyes are scanning the landscape. People also smile when they are nervous or embarrassed. When we encounter someone, it's important to think about the image we want to create.

Watch the Eyes

We've all heard the saying, "The eyes are the windows to the soul." If you pay close attention, you can detect the subtle shifts in the looks people give you, which can help understand what the other person is feeling in order to respond the right way.

I asked Van Natten about how our eyes communicate and how we can use that for a competitive edge. Or even with an employee not telling the whole truth, where a manager or coworker can zero in on what's really going on and confront. What are we looking for in the "eyes" area so we know how to respond?

Here's Van Natten:

Pupils change under certain conditions--especially when they are triggered by our emotions. When we're attracted to or like something, they grow; when we don't, they shrink. Think about this during a meeting. Your colleague is excited about the new project. You even notice that her eyes light up as she grins excessively. In reality, her genuine emotions are being immediately expressed through her eye language and pupil size. Most people lean towards a big-eyed person. It's easier to "read" them when you can see them. Be on the lookout and you'll begin to notice how others' pupils align with their feelings. Also, take note that your own pupils will call you out if your inner feelings and your outward behaviors don't match. We are looking at the eyes as we 'look inside or into the soul' of the person to validate their message. I think it is a competitive edge and we know that people with strong presence have strong eye contact and firm handshakes that support or validate their message.

Learning how to read others' eyes and the frame around them will benefit you throughout your life, says Van Natten.

Listen to Tone and Voice

According to research, tone and voice make up 38 percent of how we communicate. Important? You bet.

A new study by Michael Kraus of the Yale University School of Management has found that hearing other people's voices may even be a more reliable predictor of accurately detecting emotions than looking only at people's facial expressions. This means you could better sense someone's emotional state over the phone than seeing them face-to-face.

For example, if you notice quick breathing, that should clue you in to nervousness; a monotone voice clues you in to someone feeling down or tired; and hearing someone speak in a high-pitched and rapid manner can be a sure sign of excitement and enthusiasm on the other end.

Perhaps we should get back to more phone calls and less FaceTime, Skype or Zoom when it comes to being more attuned to the emotions in a colleague or partner's voice.

Bottom line: The better we get at this, the better we'll be at interpreting emotions in others' voices.This includes detecting emotions we don't necessarily want to know, especially if it's about us! That's where pitch may come in.

Listen to Pitch

Van Natten gives evidence of how the pitch of our voice is tied to emotion, and, often, elevates when emotions kick in. For that reason, she says, "we'd be wise to gather our emotions and check how our inner feelings emerge through our voice, even though no words are uttered."

In her book, she references a friend telling her a clever story about pitch in that the "higher the pitch, the more trash they've been talking about you!" After hearing that nugget of wisdom, Van Natten says she began to listen to other people's pitches when under stress.

She states that there's a definite connection between our tone of voice and "how we engage with others who evoke emotion from us. "Without thinking," she says, "your tone may give way to your true feelings if left unchecked. It impacts both our communication and perceptions by others."

Now if we could only figure out the secret to detecting emotions in text-based messaging, which, for most, is the primary mode of communication through smartphones. That may be my next topic of discussion with the help of the Body Language Dr.