Of all the ways to test for emotional intelligence, the marshmallow test might be my favorite. You put a child in a room, set one marshmallow in front of her and explain that, if she’s able to wait 10 minutes before eating it, she’ll get an extra marshmallow to enjoy. Then you leave her alone.
If the child can hold off, it means she has is able to self-regulate — a key component of emotional intelligence. And, as psychologist Walter Mischel has famously shown, this translates into long-term benefits. Kids who delayed gratification at age four grew up to be more organized, efficient, dependable, resilient, and successful teenagers and adults.
https://hbr.org/2015/04/how-to-look-for-emotional-intelligence-on-your-team