Susan Ochshorn is an authority on early childhood education. She reports with pleasure that many states and districts are expanding access to pre-kindergarten, but notes with unhappiness that the political leaders who are expanding early childhood education are making a terrible mistake: They are introducing four- and five-year-olds to Common Core and imposing “rigor” on these little ones.

Rigor for 4-year-olds? What about their social-emotional development, which goes hand-in-hand with cognitive skill-building? What about play, the primary engine of human development?

Unfortunately, it seems like we’re subjecting our young children to a misguided experiment.

“Too many educators are introducing inappropriate teaching methods into the youngest grades at the expense of active engagement with hands-on experiences and relationships,” Beverly Falk, author of Defending Childhood told me. “Research tells us that this is the way young children construct understandings, make sense of the world, and develop their interests and desire to learn.” She isn’t alone.

Early academic training has become an obsession among child development experts and teachers of young children as the Common Core standards have encroached upon the earliest years of schooling.

Ochshorn cites research studies that show that children actually learn better if they are not subjected to an academic curriculum too soon.

It’s not that they can’t read at this young age. Some pick it up on their own. In fact, studies have shown that children as young as 4 or 5, including those defined “at risk,” can be taught decoding skills, the foundation for reading. But research has also shown that youngsters who begin this process later than their peers — by as much as 19 months — eventually reach parity in fluency, and do even a little better on reading comprehension.

And we may well actually be doing kids harm.

Earlier this year, the report “Reading Instruction in Kindergarten: Little to Gain and Much to Lose” highlighted the research of developmental psychologist Rebecca Marcon. In a study of three different curricula, characterized as “academically oriented” or “child-initiated,” she found negative effects of overly directed preschool instruction on the later school performance of 343 students, 96% of them African-American and 75% eligible for subsidized lunch. By third grade, the differences in academic achievement were minor. But by fifth grade, students in the academic preschool earned significantly lower grades than those who had spent their days in classrooms in which they were actively engaged, with their peers and teachers, in the process of learning.