Rachel Sussman is a psychotherapist and relationship expert who counsels individuals and couples.

She says compliments are important for people's sense of self worth.

The same part of your brain lights up when you receive a compliment as when you receive cash.

A sincere, thoughtful compliment can leave an impact even years later. What is it about compliments that makes them so powerful?

Rachel Sussman, a psychotherapist and relationship expert in New York City, told INSIDER that compliments help people feel seen and acknowledged — a universal human need.

"People just want to be recognized and appreciated for the good that they do," she said. "It makes them feel really good about that person who complimented and about themselves."

A good compliment doesn't have to be related to one's appearance, Sussman says. Commending someone for a character trait, an achievement, or the effort that they put into doing something such as preparing a meal can go a long way. The most important thing is for it to be sincere.

There's also scientific proof that praise is an effective motivator. Compliments activate the reward centers in the brain, called the ventral striatum and the ventral medial prefrontal cortex. One study even found that receiving a compliment is just as thrilling to the brain as receiving cash — both are perceived by the striatum as "social rewards."

Read more: What happens to your brain when you get a like on Instagram

"If you're one of those people that can't take compliments or say 'I don't need compliments,' you should really take a look inward and try to figure out why that is," she said. It could indicate deeper issues related to low confidence or self esteem.

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