Sam Wang is an associate professor of molecular biology and neuroscience at Princeton. Sandra Aamodt is a former editor in chief of Nature Neuroscience. They are the authors of “Welcome to Your Child’s Brain: How the Mind Grows From Conception to College.”

THIS fall, one in 11 kindergarten-age children in the United States will not be going to class. Parents of these children often delay school entry in an attempt to give them a leg up on peers, but this strategy is likely to be counterproductive.

The practice, called redshirting — from the term for allowing college athletes to delay participation in sports to prolong their eligibility — also has a connection to children’s sports. As sports-minded parents know, physical maturity allows older children to perform better. Coaches often mistake this difference for natural aptitude and respond by giving the older children on their T-ball or soccer teams more opportunities to improve their skills. And those athletes tend to gain a lasting competitive advantage. Does a similar approach work for academic achievement?

Teachers may encourage redshirting because more mature children are easier to handle in the classroom and initially produce better test scores than their younger classmates. In a class of 25, the average difference is equivalent to going from 13th place to 11th. This advantage fades by the end of elementary school, though, and disadvantages start to accumulate. In high school, redshirted children are less motivated and perform less well. By adulthood, they are no better off in wages or educational attainment — in fact, their lifetime earnings are reduced by one year.

In short, the analogy to athletics does not hold. The question we should ask instead is: What approach gives children the greatest opportunity to learn?

Parents who want to give their young children an academic advantage have a powerful tool: school itself. In a large-scale study at 26 Canadian elementary schools, first graders who were young for their year made considerably more progress in reading and math than kindergartners who were old for their year (but just two months younger). In another large study, the youngest fifth-graders scored a little lower than their classmates, but five points higher in verbal I.Q., on average, than fourth-graders of the same age. In other words, school makes children smarter.

The benefits of being younger are even greater for those who skip a grade, an option available to many high-achieving children. Compared with nonskippers of similar talent and motivation, these youngsters pursue advanced degrees and enter professional school more often. Acceleration is a powerful intervention, with effects on achievement that are twice as large as programs for the gifted. Grade-skippers even report more positive social and emotional feelings.

These differences may come from the increased challenges of a demanding environment. Learning is maximized not by getting all the answers right, but by making errors and correcting them quickly. In this respect, children benefit from being close to the limits of their ability. Too low an error rate becomes boring, while too high an error rate is unrewarding. A delay in school entry may therefore still be justified if children are very far behind their peers, leaving a gap too broad for school to allow effective learning.

Parents want to provide the best environment for their child, but delaying school is rarely the right approach. The first six years of life are a time of tremendous growth and change in the developing brain. Synapses, the connections between brain cells, are undergoing major reorganization. Indeed, a 4-year-old’s brain uses more energy than it ever will again. Brain development cannot be put on pause, so the critical question is how to provide the best possible context to support it.

For most children, that context is the classroom. Disadvantaged children have the most to lose from delayed access to school. For low-income children, every month of additional schooling closes one-tenth of the gap between them and more advantaged students. Even without redshirting, a national trend is afoot to move back the cutoff birthdays for the start of school. Since the early 1970s, the date has shifted by an average of six weeks, to about Oct. 14 from about Nov. 25. This has the effect of making children who would have been the youngest in one grade the oldest in the next-lower grade; it hurts children from low-income families the most.

Some children, especially boys, are slow to mature emotionally, a process that may be aided by the presence of older children. Kindergartners show age-related differences in social acceptance and self-perceptions, but these differences usually even out by first grade. The benefits of interacting with older children may extend to empathetic abilities. Empathy requires the ability to reason about the beliefs of others. This capacity relies on brain maturation, but it is also influenced by interactions with other children. Having an older (but not younger) sibling speeds the onset of this capacity in 3- to 5-year-olds. The acceleration is large: up to half a year per sibling. Although nearly all children reach a mature level of understanding by age 6, there may be lasting social advantages to developing this ability earlier. Parents concerned about a child’s emotional maturity might consider that frequent interaction with more mature classmates could help the developmental process along.

The initial redshirt advantage may disappear because children are not on a fixed trajectory but learn actively from teachers — and classmates. It matters very much who a child’s peers are. Redshirted children begin school with others who are a little further behind them. Because learning is social, the real winners in that situation are their classmates.