A new study finds that children develop a sense of self-esteem earlier than previously thought. (iStock)

Children develop self-esteem by age 5, much earlier than previously thought, according to new research that suggests children gain either a positive or negative view of themselves before they begin formal schooling.

The researchers found that self-esteem at age 5 is as strong as those measured in adults.

“We were surprised to find is how strong it was,” said Dario Cvencek, a research scientist at the University of Washington’s Institute for Learning & Brain Sciences and a co-author of the study. “The first five years seems to be a foundation on which children build for the rest of their lives.”

Still, self-esteem can change — either positively or negatively — as children grow, Cvencek said. “At age 5, it’s developed and already pretty strong,” he said. “But any traumatic experience can affect you. We do think it’s malleable, but it starts a lot earlier than previously thought.”

The findings, published in the January 2016 issue of the Journal of Experimental Social Psychology, come from a new test designed to measure self-esteem in 5-year-olds, the youngest age group to be measured.

Previous tests of self-esteem required children to be able to read and to be able to understand what is meant by being a good or bad person, Cvencek said. “Preschoolers can answer questions about narrow, concrete skills, such as ‘I am good at running’ or ‘I’m good at letters,’ ” he said. “But they have difficulty providing reliable answers or understanding what it means if you ask, ‘Are you a good person?’ ”

That understanding usually comes around 8 years of age, he said.

So researchers gave the 5-year-olds several flags and played a game in which they were told some of the flags were “me” and some “not me” and asked them to respond with the flags to a series of positive and negative words broadcast over a loudspeaker. The children had to combine words and press buttons on a computer to signal whether they associated the “good” or “bad’ words with the “me” flags or not.

More than 230 children from the Seattle area participated in the study, which found that about 90 percent of the children had a positive self-esteem, while just 10 percent expressed a negative self-esteem.

Researchers also measured gender identity and found that children with high self-esteem strongly identified with their own gender and preferred their own gender. Although both boys and girls preferred their own gender, the effect was stronger in girls.

In other words, girls with high self-esteem tend to prefer to associate with other girls, and to think that girls are better than boys.

The researchers plan to follow the children in the study to examine whether self-esteem measured in preschool can predict outcomes later in childhood, such as academic achievement, and whether self-esteem changes with experience.

The research comes as policy leaders on the local, state and federal level have increasingly stressed the value of early childhood education and a national shift in thinking that the earliest years are an important window for growth and development.