You could look at what it does but babies are not very coordinated or skilled so you need to use clever methods.

你可以观察婴儿,但婴儿不怎么配合,或者说他们的言语技能并不熟练,所以你必须要用精巧的方法才能做到

耶鲁公开课 - 心理学导论课程节选

It's not something that you can either explain in word or describe.

不是你可以用言语,来解释和描述的。

普林斯顿公开课 - 人性课程节选