Finger tracing enhances learning: Evidence for 100-year-old practice used by Montessori

Finger tracing has been used by teachers to help students learn for more than a century. In the early 1900s, education pioneer Montessori encouraged young children to trace over letters of the alphabet made from sandpaper with their index fingers, based on the intuition that a multi-sensory approach (i.e., visual, auditory, tactile, and kinesthetic) to learning would be most effective. In 1912, Montessori noticed that children, after mastering the sequence of tracing a letter with their index finger, "took great pleasure" in closing their eyes and trying to recall it.

source https://phys.org/news/2021-09-finger-evidence-year-old-montessori.html