Because they are still visualizing the words. It is not unautomatic anymore, which also explains why kids live like kids, why they are able to appreciate the simplist of things, to be mesmerized by airplane up there.

因为他们还在脑海里把单词变成图像，但大人要有意识地才能形成图像，这就解释了为什么孩子活着这么有童真，为什么他们会感激简单的东西，看到飞机都这么高兴。