When a small child encounters an angry dog, she instinctively knows that bared fangs signal great danger even without any previous learning. The encoding for such recognition goes deep.

• 小孩面对一只生气的狗，即使之前没经过任何学习，她也本能地知道露出的犬牙意味着危险，这种认知编码深藏在人脑中。