다음 문장...해석해주세요...특히..learn이 단어해석이 잘 안되네요..

test have shown that children born first are best able to keep secrets.
children born later learn the habit of running to older brothers and sisters with any important news
; they never completely lose this habit even after they grow up.

위문장 좀 해석해주세요...특히..위에 쓰인 learn이 여기에서는 무슨뜻으로 쓰였는지 알려주세요...