Sometimes, the signs that someone is smart are easily recognizable. Other giveaways are more subtle.

The top one: being a good listener, says New York-based psychotherapist and career coach Jenny Maenpaa.

People who “are able to perceive an interaction holistically, rather than just being in the moment and responding to the last thing you said with the first thing they thought of” are usually highly intelligent, Maenpaa tells CNBC Make It.

This skill is also known as active listening, and it requires more than just sitting in silence while someone speaks.

“Active listening is when someone can listen to you at length, truly taking in what you’re saying, and not interrupt,” Maenpaa says. “Active listeners respond with questions because they are genuinely curious about what you’re saying. They can hold their questions in their mind until you finish instead of interrupting to clarify or to share a thought they had just because you reminded them of it.”

Successful people can use this skill to foster relationships and build trustand with colleagues, bosses, mentors or anyone else around them. Many professionals believe that they’re active listeners, but 70% of them actually exhibit poor listening habits in the workplace, resulting in misunderstandings and damaged friendships, according to a 2020 University of Southern California report.

Some people are “naturally gifted with [active listening skills] from an early age, and often receive feedback like, ‘You’re so easy to talk to!’ or ‘I feel like I’m the only person in the room when we talk,’” says Maenpaa.

Others can develop the ability through practice. Maintain eye contact with your conversation partners, sit still instead of fidgeting, and wait for people to finish their thoughts before speaking, psychologist and mental health coach Amanda O’Bryan recommended in a 2022 Positive Psychology blog post.

Internalizing what the other person is saying, rather than focusing exclusively on your own thoughts, can also help.

“Active listeners will be able to circle back to an earlier point in the conversation and say, ‘What you just said reminds me of something you said a few minutes ago,’ and make connections or draw themes from the conversation,” Maenpaa says.

The skill can help you create long-lasting connections with the people around you, she adds: “Talking to someone who is an active listener will often have someone leaving the conversation feeling seen, heard, and validated from their interaction.”

CNBC