The Knowledge Gap Hypothesis explains that knowledge, like other forms of wealth, is often differentially distributed throughout a social system. Specifically, the hypothesis predicts that “as the infusion of mass media information into a social system increases, higher socioeconomic status segments tend to acquire this information faster than lower socioeconomic-status population segments so that the gap in knowledge between the two tends to increase rather than decrease” Phillip J. Tichenor, then Associate Professor of Journalism and Mass Communication, George A. Donohue, Professor of Sociology, and Clarice, N. Olien, Instructor in Sociology – three University of Minnesota researchers – first proposed the knowledge gap hypothesis in 1970.

（http://en.wikipedia.org/wiki/Knowledge_gap_hypothesis）

用简单的话来说：

社会经济地位高者通常比地位低者更快地获得信息。大众传播媒介传递的信息越多，两者之间的知识鸿沟也就越有扩大的趋势。

知沟理论假说，在当前传播媒介越来越纷繁复杂的情况下，受到一定的挑战，但是仍具意义。个中缘由，大家可以细细品味。