Beginning at 9–10 months of age when infants begin to crawl and then when they begin to walk around 12 months of age, they begin to develop capacities to physically explore the world away from their mother.
出生後的9到10個月開始，嬰兒會開始爬行；約12個月大的時候便學會走路，並開始發展遠離母體探索世界的能力。