Most people take the elements of the topic, memorize the data, and then look for the relationship between the data in ways that are familiar. That is the process of understanding. If you think about it, memorization of data and understanding of the topic are two very different things. If you throw in accuracy of observation, and then interpretation of what is being observed, and on top of that you throw in the natural bias that each person possesses, then what you have is an almost unique interpretation of an event, even though everyone saw it and heard it at exactly the same moment.
