Can anyone correct this spoken lecture of mine that I transcribed it to the print? The chapter is about "attention", probably one of the most familiar concepts that we are dealing with in everyday life. But when it comes to giving a clear explanation, even the greatest cognitive psychologists will become empty-handed. Once, William James said that "Everyone knows what attention is, it's the taking possession by the mind in clear and vivid form, one out of what seem several simultaneously possible objects or trains of thoughts. It implies withdrawal from somethings in order to deal effectively with others." But, one century later, William pashler said that "Nobody knows what attention is, and maybe there is no "it" to define it". What I want to arrive at is that there always have been these kinds of dichotomies, but because nowadays we are using this term much more than ever before we need a clearer definition in order to work on it. Neisser's working definition of attention is that "Attention is the allocation of resources and processing to a region or object", so attention is a resource-demanding process. And our resources are limited, that's why we cannot attend to everything. Further, four networks of attention posed by Posner: Sustained attention, opening attention, selective attention, executive functions. Further explanation will be presented another time.