They may know that they are not wanted. The baby is more peaceful when alone. Certain people terrify them, toy mobiles upset them, rocking irritates them, and changes in weather make them restless. They may be colicky, and their digestive systems may not tolerate food that is too hot or too cold. If the needs of the baby are ignored the child becomes insecure.
Sensitive babies are also very creative and aware.
They may walk early or smile a lot. When they begin to crawl they search out ways to alleviate their apprehension. When old enough, they spend time alone to regain their balance and energy. This hyper-awareness to their environment makes HSPs cautious. They are not known for their rash actions.