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Summary Article: Knowledge Gap Hypothesis from Encyclopedia of Science and Technology Communication

The 1970s marked the formalization of the knowledge gap hypothesis, developed by Philip J. Tichenor, George A. Donohue, and Clarice N. Olien, known as the Minnesota team, which proposed that the segments of a population that have higher socioeconomic status (SES) tend to acquire information flowing from the media at a faster rate than do segments with lower status and that the gap in knowledge between these segments tends to increase rather than decrease over time. The knowledge gap hypothesis does not suggest that the lower-SES population segments remain completely uninformed, but that the growth of knowledge is relatively greater among the higher-SES population segments. These gaps in knowledge between high-SES and low-SES populations can lead to what scholars such as Kasisomayajula Viswanath and John Finnegan have referred to as the information “haves” and “have-nots.”

Historical Underpinnings

Gaps in knowledge are nothing new and have always been found among groups, thus laying the foundation for the knowledge gap hypothesis. Earlier evidence of the underpinnings of the knowledge gap hypothesis was first found by Herbert H. Hyman and Paul B. Sheatsley in 1947. In their public information campaign research, they observed that information and knowledge rarely spread equally to all societal groups. Similar observations noting that those with more education had better information and knowledge acquisition outcomes than those with little education were reported by others. Earlier intellectual contributions to the knowledge gap hypothesis can also be found in research emerging from the literature on rural sociology, diffusion of innovations, public opinion, and information campaigns. Theorizing about the social structural influences of media and the contributory aspects of the knowledge gap hypothesis can be seen in the mass media effects literature as well. However, it was Tichenor, Donohue, and Olien's celebrated 1970 study, “Mass Media Flow and Differential Growth in Knowledge,” that first examined whether or not factors such as education level or socioeconomic status actually make a difference in knowledge acquisition.

The knowledge gap literature presents conflicting evidence, however, with some studies suggesting that media-generated information increases knowledge gaps, whereas other studies find no evidence of widening knowledge gaps. Along with these conflicting findings, many researchers have taken exception to the implication that SES may affect the ability to learn. As a result, the knowledge gap hypothesis was revised by the Minnesota team and later refined by others to address these concerns. The knowledge gap hypothesis continues to generate a lot of interest worldwide.


A central point of the knowledge gap hypothesis concerns the acquisition and control of knowledge, which scholars suggest is the basis of social power and social action. As articulated by Sir Francis Bacon, “knowledge is power.” Tichenor, Donohue, and Olien have identified several predictors of why knowledge gaps should appear and widen with increasing levels of media flow into communities. Also important to note is that in the initial conceptualization of the knowledge gap hypothesis, education was used as the indicator of SES. People with more formal education were assumed to have better communication skills (higher reading and comprehension skills). Further, people who are already better informed were believed better able to store information more easily, draw from this store or background knowledge, and be aware of a topic when it is first presented. People with more education were generally seen as having a more relevant social context (that is, more reference groups and more interpersonal contacts with whom to discuss issues). More education also generally determines a person's selective exposure, acceptance, and retention of information, which some have suggested is a prerequisite for acquiring knowledge. Finally, in general, the flow of mass media information is geared toward the interests and tastes of those with more education or a higher SES status.

Knowledge Gap Hypothesis Applications

In addition to Tichenor, Donohue, and Olien's ground-breaking research, other noteworthy contributions came from works by Herbert H. Hyman and Paul B. Sheatsley (1947), James S. Ettema and F. Geraldine Kline (1977), Brenda Dervin (1980), Cecilie Gaziano (1983), Kasisomayajula Viswanath and John Finnegan (1996), and Kasisomayajula Viswanath, Shoba Ramandahn, and Emily Kontos (2007). These scholars' work, along with that of others, has presented a critical foundation for the formalization, refinement, and expansion of the knowledge gap hypothesis.

Although Tichenor, Donohue, and Olien's original knowledge gap hypothesis was applied primarily to public affairs and science news, in the United States and worldwide, knowledge gap theory has also been used to examine knowledge of politics, education, space research, environment, international issues, mass media issues, and health.

Currently, there is a great deal of focus on health issues in the United States. Several knowledge gap applications have examined health-related issues, such as diet and cardiovascular disease, health information campaigns, smoking behavior, childbirth, and infant development. For example, in one 2008 study by Minsun Shim using the National Cancer Institute's 2003 Health Information National Trends Survey (or HINTS), a survey that routinely collects nationally representative data about the American public's use of cancer-related information, the researcher applied the knowledge gap hypothesis to examine Internet use for cancer information. This study examined disparities in online information seeking by education and ethnicity, as well as subsequent gaps in cancer knowledge. Data supported the hypothesis that higher-education groups and white Americans were more likely to use the Internet for cancer information than were their counterparts, and that online information seeking enlarged to some degree the cancer knowledge gaps between education groups.

Future Work

Future knowledge gap applications should continue to focus on the astonishing advances in new media technology, including the convergence of traditional media (print, television, radio) with new media (computers, Internet, cell phones, iPods, CD-ROMs, video, audio). A groundswell of new information and information-delivery opportunities is emerging, thereby extending the information landscape beyond time and space and extending the reach of information and communication efforts. However, challenges remain. The digital divide—the perceived gap between those who have access to the latest information technologies and those who do not—continues to be an important concern. Research still reveals that more-educated and higher-income groups have greater access to both traditional media and new media information resources compared to lower-SES groups, demonstrating the persistence of the digital divide and contributing to ongoing knowledge gaps among various groups.

Scholars have also called for more examinations that seek to tease out knowledge measurement issues by utilizing cross-sectional, panel, and time-trend studies to better examine change. There is also a paucity of research that seeks to elucidate the factors that reduce knowledge gaps and erase communication inequalities. Some recent and promising work in the domain of health communication builds on the knowledge gap hypothesis, combining the social epidemiological approach with the structural approach in mass communication and offering some clarity regarding how communication inequalities may contribute to inequalities in health.

The Structural Influence Model of Health Communication (SIM), as proposed by Viswanath, Ramanadhan, and Kontos in 2007, further explores communication inequality, defined as the differences among social groups in their ability to generate, disseminate, and use information at the macrolevel and to access, process, and act on information at the individual level. This emerging framework posits a connection between social determinants of health outcomes and a broad range of mass and interpersonal communication factors. In our fast-paced and ever-changing social and information landscape, the knowledge gap hypothesis and its refinements represent a tenable lens with which to examine these social, informational, and technological changes and challenges.

See also

Communication Campaigns in Health and Environment, Digital Divide, Health Communication and the Internet, Health Literacy, Information Seeking and Processing

Further Readings
  • Coleman, J. S., Campbell, E. Q., Hobson, C. J., McPartland, J., Mood, A. M., Weinfeld, F. D., et al. (1966). Equality of educational opportunity (No. OE- (38001). Washington, DC: U.S. Department of Health, Education, and Welfare, Office of Education, National Center for Education Statistics.
  • Dervin, B. (1980). Communication gaps and inequities: Moving toward a reconceptualization. In B. Dervin & M. J. Voight (Eds.), Progress in communication science (p. 2). Norwood, NJ: Ablex.
  • DiMaggio, P.; Hargittai, E.; Neuman, R.; Robinson, J. Social implications of the Internet. Annual Review of Sociology 27 : 307-336., 2001.
  • Donohue, G. A.; Tichenor, P. J.; Olien, C. N. Mass media and the knowledge gap: A hypothesis reconsidered. Communication Research 2 : 3-23., 1975.
  • Ettema, J. S.; Kline, F. G. Deficits, differences, and ceilings: Contingent conditions for understanding the knowledge gap. Communication Research 4 ((2)) : 179-202., 1977.
  • Eveland, W.; Scheufele, D. Connecting news media use with gaps in knowledge and participation. Political Communication 17 ((3)) : 215-237., 2000.
  • Gaziano, C. Knowledge gap: An analytical review of media effects. Communication Research 10 : 447-486., 1983.
  • Gaziano, C. Forecast 2000: Widening knowledge gaps. Journalism and Mass Communication Quarterly 74 ((2)) : 237-264., 1997.
  • Hyman, H. H.; Sheatsley, P. B. Some reasons why information campaigns fail. Public Opinion Quarterly 11 : 412-423., 1947.
  • Kwak, N. Revisiting the knowledge gap hypothesis: Education, motivation, and media use. Communication Research 26 ((4)) : 385-413., 1999.
  • Shim, M. Connecting Internet use with gaps in cancer knowledge. Health Communication 23 ((5)) : 448-461., 2008.
  • Star, S. A.; Hughes, H. M. Report on an educational campaign: The Cincinnati Plan for the United Nations. American Journal of Sociology 55 ((4)) : 389-400., 1950.
  • Tichenor, P.; Donohue, G.; Olien, C. Mass media flow and differential growth in knowledge. Public Opinion Quarterly 34 : 159-170., 1970.
  • Viswanath, K., & Finnegan, J. R. (1996). The knowledge gap hypothesis: Twenty-five years later. In B. Burleson (Ed.), Communication yearbook (Vol. 19, pp. 187-227). Thousand Oaks, CA: Sage.
  • Viswanath, K., Ramanadhan, S., & Kontos, E. Z. (2007). Mass media and population health: A macrosocial view. In S. E. Galea (Ed.), Macrosocial determinants of population health (pp. 275-294). New York: Springer.
  • Wallington, Sherrie Flynt
    Copyright © 2010 by SAGE Publications, Inc.

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