Building upon early research from rural sociology, diffusion of innovations, public opinion poll data, and information campaigns, Tichenor et al. (1970, 159–160) posed the hypothesis: “As the infusion of mass media information into a social system increases, segments of the population with higher socioeconomic status (SES) tend to acquire this information at a faster rate than the lower status segments, so that the gap in knowledge between these segments tends to increase rather than decrease.” The less advantaged were predicted to gain knowledge but at a slower rate than more advantaged groups. The gap can be studied at one time point or over time. Tichenor et al., also known as the Minnesota Team, focused on public affairs and scientific knowledge. They assumed that knowledge growth was irreversible (although forgetting can occur) and that ceiling effects occurred at varying rates for different SES groups or else had not been reached.
The most frequent indicator of SES is level of formal education, although researchers also have used income and, less frequently, occupation (Viswanath & Finnegan 1996; Gaziano 1997). Missing data are a greater problem with income questions than education or occupation measures, and occupation can be difficult to code. Knowledge is defined as information acquired and retained by people through learning processes. Gap means the relation between SES and knowledge. Knowledge has been measured as simple awareness or as in-depth knowledge, either in open-ended or closed-ended questions, or both. Incidentally, awareness knowledge gaps can be narrowing while in-depth knowledge gaps are increasing, and knowledge measured with open-ended questions does not necessarily decrease the relation to SES, compared with closed-ended questions with objectively defined answers. Additionally, media use, attention, or publicity should vary because the prediction concerns changing levels of media information diffusion.
Operational definitions of knowledge gap include differences in mean knowledge scores among SES groups, differences in proportions of SES groups possessing any knowledge, correlations between knowledge and SES (Viswanath & Finnegan 1996; Gaziano 1997), statistical interactions between education and news media use in hierarchical multiple regression analyses of cross-sectional data (Kwak 1999; Eveland & Scheufele 2000), and comparisons of communities that vary in structural characteristics (Tichenor et al. 1980; Donohue et al. 1986). Inaccurate information is seldom examined; it tends to circulate more often among lower SES groups than higher SES groups (Gaziano 1997).
Conditions Under Which Gaps Increase Or Decrease
The Minnesota Team reported that differentials decreased when (1) conflict was associated with issues (bringing them to the attention of all social groups), (2) levels of media coverage were high and sustained over time, (3) levels of interpersonal discussion about topics were high, (4) community structures were relatively smaller and more homogeneous, as opposed to larger, heterogeneous structures (that tend to have more groups active on issues and greater complexity of communication channels), (5) issues had high levels of basic concern to communities, and (6) forgetting occurred over time among all groups (Tichenor et al. 1980). Other work corroborated and extended these findings (Viswanath et al. 1995).
The majority of studies find knowledge inequalities (Viswanath & Finnegan 1996; Gaziano 1997). Conditions under which gaps tend to arise include those in which topics have differential appeal to SES groups or in which there are high levels of organized group activity, which tend to create greater interest in issues, although group ability to define issues or control information dissemination can lead to restriction of information (Tichenor et al. 1980; Holst 2000). Knowledge gaps can develop between small, homogeneous communities and larger, more heterogeneous communities as metropolitan newspapers pull back from regional coverage in order to maximize profits (Donohue et al. 1986). Smaller communities can be less attractive markets to metropolitan dailies because of rural location, agricultural orientation, and lower-income populations.
Ettema and Kline (1977) and Dervin (1980) were early critics of the knowledge gap perspective; however, analysis of their critiques showed that their models, units of analysis, and assumptions were different from those of the Minnesota Team, leading to different kinds of hypotheses and different explanations (Gaziano & Gaziano 1999). The Minnesota Team conducted a systematic program of research spanning nearly three decades that located cause in the social stratification of collectivities (especially communities) and that saw knowledge gaps resulting from social control processes, with knowledge control by elites and/or pressures for social change as potential outcomes (Tichenor et al. 1980; Viswanath & Finnegan 1996).
Ettema & Kline (1977) were concerned with social–psychological, individual-level causal factors, audience-related elements (skills, motivation, media behavior) and message-related elements (ceiling factors), in order to explain knowledge differentials as “communication effects gaps,” in terms of “differences” rather than “deficits.”
Dervin’s (1980) model was an intra-individual, cognitive-processing model with cybernetic and library science elements. She characterized data on gaps as “numeric myths” with a “blame the victim” perspective. Her unit of analysis was the “gap-bridging instance,” and she perceived the debate in terms of “information gaps” and “sense-making.”
A fourth model brought the concepts of culture, belief systems, community networks, and other networks to center on knowledge differentials among social groups (Gaziano & Gaziano 1999).
Future Research Directions
The relative contributions of print and broadcast media to knowledge inequities have been little studied, particularly radio, magazines, and the Internet. Use of television and, to a lesser extent, newspapers contributed to smaller knowledge gaps when campaign interest and key demographics were controlled in an analysis of national election data (Eveland & Scheufele 2000). After controlling for demographics, Kwak (1999) found that high exposure to television news was related to smaller knowledge differentials during the 1992 presidential campaign in Dane County, WI, a pattern for television corroborated by Liu and Eveland (2005) with national data. Kwak (1999) also found that close attention to news of the campaign in newspapers among those who were the most interested in the election diminished the educationbased knowledge gap. Eveland and Scheufele (2000) expected that newspaper use would lead to larger knowledge gaps because newspaper access frequently depends on education, but they found the opposite result. In contrast, Liu and Eveland (2005) observed an influence of newspaper use and attention on increased knowledge disparities.
Since most knowledge gap work involves cross-sectional data, future research should include more panel or time-trend studies to better study change (Holst 2000; Holbrook 2002). Also needed is more study of factors that reduce gaps, such as motivation, including the conditions under which motivation is related to SES and when it is not (Kwak 1999); new communication technologies, especially the Internet; childrearing patterns and family communication styles (Gaziano 2001); school curricula oriented toward enhancing adolescent–parent communication and political learning (McDevitt & Chaffee 2000); and different communication (Eveland & Scheufele 2000) and cultural (Gaziano & Gaziano 1999) contexts. In addition, more study is needed of measurement issues, such as improved knowledge measurement and increased number of indicators of key concepts (Viswanath & Finnegan 1996; Liu & Eveland 2005).
- Dervin, B. (1980). Communication gaps and inequities: Moving toward a reconceptualization. In B. Dervin & M. J. Voight (eds.), Progress in communication sciences, vol. 2. Norwood, NJ: Ablex, pp. 73 –112.
- Donohue, G. A., Tichenor, P. J., & Olien, C. N. (1986). Metro daily pullback and knowledge gaps: Within and between communities. Communication Research, 13(3), 453 – 471.
- Ettema, J. S., & Kline, F. G. (1977). Deficits, differences, and ceilings: Contingent conditions for understanding the knowledge gap. Communication Research, 4(2), 179 –202.
- Eveland, W. P., Jr., & Scheufele, D. A. (2000). Connecting news media use with gaps in knowledge and participation. Political Communication, 17(3), 215 –237.
- Gaziano, C. (1997). Forecast 2000: Widening knowledge gaps. Journalism and Mass Communication Quarterly, 74(2), 237–264.
- Gaziano, C. (2001). Toward a conceptual framework for research on social stratification, childrearing patterns, and media effects. Mass Communication and Society, 4(2), 219 –244.
- Gaziano, E., & Gaziano, C. (1999). Social control, social change, and the knowledge gap hypothesis. In D. Demers & K. Viswanath (eds.), Mass media, social control, and social change: A macrosocial perspective. Ames, IA: Iowa State University Press, pp. 117–136.
- Holbrook, T. M. (2002). Presidential campaigns and the knowledge gap. Political Communication, 19(4), 437– 454.
- Holst, I.-A. (2000). Realitätswahrnehmung in politischen Konflikten. Grundlagen einer Theorie der Wissenskluft [Beliefs about reality during political controversies: Foundations of a theory of knowledge gaps]. Constance: UVK Universitätsverlag.
- Kwak, N. (1999). Revisiting the knowledge gap hypothesis: Education, motivation, and media use. Communication Research, 26(4), 385 – 413.
- Liu, Y.-I., & Eveland, W. P., Jr. (2005). Education, need for cognition, and campaign interest as moderators of news effects on political knowledge: An analysis of the knowledge gap. Journalism and Mass Communication Quarterly, 82(4), 910 –929.
- McDevitt, M., & Chaffee, S. (2000). Closing gaps in political communication and knowledge: Effects of a school intervention. Communication Research, 27(3), 259–292.
- Tichenor, P. J., Donohue, G. A., & Olien, C. N. (1970). Mass media flow and differential growth in knowledge. Public Opinion Quarterly, 34(2), 159 –170.
- Tichenor, P. J., Donohue, G. A., & Olien, C. N. (1980). Conflict and the knowledge gap. In Community conflict and the press. Beverly Hills, CA: Sage, pp. 175 –203.
- Viswanath, K., & Finnegan, J. R., Jr. (1996). The knowledge gap hypothesis: twenty-five years later. In B. R. Burleson (ed.), Communication Yearbook 1996. Thousand Oaks, CA: Sage, pp. 187–227.
- Viswanath, K., Finnegan, J. R., Jr., Hertog, J., Pirie, P., & Murray, D. M. (1995). Community type and the diffusion of campaign information. International Communication Gazette, 54(1), 39 –59.