When it comes to learning, babies often show patterns that adults find somewhat baffling. One week, you are sure your baby has mastered walking, and the next week he is crawling again. One day, he has graduated from putting everything in his mouth and the next day, everything is right back in there. This two-steps-ahead, one-step-back pattern happens across many diverse areas and at many different points throughout the first years. Scientists refer to it as the U-Shaped pattern of learning. Why do babies display this pattern? Although your baby is not quite at this stage yet, a topic such as verb conjugation is a perfect illustration of what is going on.

• A preschooler’s boat sinks in the bathtub and he says, “It sank.” He knows “sank” is the past tense of “sink” because he has heard you use these words correctly. He is mastering language by imitation.

• Two weeks later, however, the boat sinks again. “It sinked,” he says. This “step backward” has occurred because he has deduced something about the regularities about speech. He has applied the rule that to create the past tense, you add “ed” to the present tense of the word.

• Another two weeks go by and the boat sinks yet again. “It sank,” the boy says this time. Increased exposure to language has taught him that there are exceptions to the rules.

This U-Shaped pattern of learning can be seen in many different areas of development throughout your baby’s first year. So the next time your child reverts from walking to crawling, goes back to mouthing every toy in sight or gets to the stage when he tells you his boat “sinked,” don’t despair that he will never get into preschool; congratulate him on his great advance!