自上世纪90年代起，传播学领域开始对自身研究历史进行自反性书写，反思并批判了传统意义上的智识史与传记史。本研究以此为基础，借助知识社会学视角，从内部主义和外部主义两种取向出发，重新解释美国早期“知沟假说”的提出背景与理论推广过程。研究发现，从外部视角来讲，知沟假说的提出受到了20世纪60年代美国社会改革运动和教育学研究的重要影响，可以被视为传播学对“伟大社会改革”的一次直接介入；从内部视角来讲，知沟假说作为一项研究议题，之所以可以获得较大发展，与明尼苏达小组的学术推广工作，以及美国北部农业州各增地学院的参与息息相关。本研究的理论意义在于以知沟假说为例，实践并倡导一种知识社会学取向的传播学史研究。

Since 1990s, communication scholars began to self-reflect the construction of their disciplinary history and criticize traditional intellectual history and biographical history writing. Based on sociology of knowledge, this study adopts both internal and external perspective to re-examines the social background and academic diffusion of knowledge Gap Hypothesis during 1970s. This study finds that the birth of knowledge Gap Hypothesis is embedded in theGreat Society Plan and relevant education studies during 1960s. Besides, the development of knowledge Gap Hypothesis as a research agenda is assisted by both the efforts of Minnesota team and various scholars from land-grant universities in northern agricultural states. The significance of this study is to advocate an investigation of history of communication studies using sociology of knowledge.