This is a reflex test... It's called the Asymmetrical Tonic Neck Reflex (ATNR). This reflex should normally integrate (go away) by around 6 months of age. If it's still present later, it can affect posture, hand-eye coordination, and even reading and writing skills. You can check this on your child by having them in a "puppy push-up" position, gently turning their head side to side, and watching to see if their arms straighten or bend in response. For more reflex testing examples, DM us the word