Ask preschooler Zane Pike to write his name or the alphabet, then watch this 4-year-old's stubborn side kick in. He spurns practice at school and tosses aside workbooks at home. But Angie Pike, Zane's mom, persists, believing that handwriting is a building block to learning.

She's right. Using advanced tools such as magnetic resonance imaging, researchers are finding that writing by hand is more than just a way to communicate. The practice helps with learning letters and shapes, can improve idea composition and expression,...