Project Research


Charles Darwin’s notions about the origins and evolution of species are widely accepted by biologists and other scientists but critics of modern evolutionary theory argue for various alternatives. Among those is intelligent design – the idea that some aspects of life are shaped by intelligent or supernatural forces, such as the hand of God. Efforts to include this idea in high school biology classes, however, have been consistently rejected by the courts and so opponents of modern evolutionary theory now promote an approach called “teach the controversy,” (TTC). TTC argues that science teachers should be able to teach scientific evidence that appears to contradict evolution along with evidence that appears to support it. This controversy has received plentiful attention in the mass media and a number of partisan national groups have coalesced around the debate.

1590709_origWe designed this project to examine how people who are highly involved in controversial topics–topics like these science-and-religion debates–respond to media coverage of those topics. Research has shown that people with strong opinions about an issue, particularly those involved in advocacy organizations, tend to view balanced media coverage of the topic as biased or hostile to their own positions. Each group sees the same content as biased in favor of the other side and the resulting skewed perceptions may prevent partisans from giving balanced information a fair hearing. This so-called “hostile media effect” has been consistently observed across a variety of issues, from the Israeli-Palestinian conflict to debates over animal research, but scholars have offered differing explanations. One perspective is that strong preexisting attitudes are responsible, while another is that group affiliation, and perceived threats to that group, leads to perceptions of bias in the media.

mHeaderWith generous support from the John Templeton Foundation, we developed an experiment to test whether preexisting attitudes, group identity or some combination of both factors might account for perceptions of hostile media bias. We recruited members of the Discovery Institute (DI), a large national group that promotes the teach-the-controversy idea and the National Center for Science Education (NCSE), a group that resists challenges to Darwinian evolution, to participate in our online experiment.

ncselogoParticipants viewed a simulated USA Today op-ed article but they were randomly assigned to different versions of the articles. The versions were manipulated to contain neutral or slanted content (balanced, or slanted toward TTC or toward evolution) and the versions were attributed to neutral or partisan sources (journalist, pro-TTC spokesperson or pro-evolution spokesperson). We expected that if preexisting attitudes were the dominant cause of biased perceptions then slanted content would engage participants’ attention while if group identification were the major factor then a partisan source would primarily influence the degree to which they saw the article as biased toward or against their own position.

Given the logic behind each explanation, we were not surprised to find that both source cues and content variations strongly predicted relative perceptions of bias. (Respondents’ bias evaluations in all conditions are illustrated in Figure 1 below.) An outgroup source, for example, resulted in both groups rating the article as unfavorably biased even when the content was neutral and balanced. DI members saw the article attributed to the neutral source as biased but, predictably, an ingroup source lessened this perception of bias. NCSE members showed a similar pattern although they saw the article as even-handed regardless of whether it was attributed to an ingroup or neutral source.

But alongside these source effects, participants were equally strongly affected by article slant. When the content was slanted in favor of a group’s position it was received more favorably than when it was balanced and the reverse was true for unfavorable slant. We also found that among DI members, content slant and source worked together to shape ratings of bias.  They saw less bias against them when a pro-evolution article was attributed to a pro-TTC source, and less bias for them when a pro-TTC article was attributed to a pro-evolution source. We did not observe a similar pattern among NCSE members.

Figure1ForWebSource and content slant affects perception of bias

This figure shows that both the source and slant of the message affected whether participants saw the article as biased for or against them. Values above 0 represent perceived bias in favor of “teach the controversy” (TTC); below 0 they represent perceived bias favoring evolution.  Group means are listed along the bottom row; asterisks represent significant differences between groups at p<.05 or better; the pound symbol (#) indicates significant differences at the p<.10 level.

The findings show many similarities but also some important differences in the way these two adversarial groups responded to the source and content manipulations. The absence of some of the effects for NCSE members might be explained by their perception—given favorable court rulings and the current teaching regime–that the pro-evolution perspective is the status quo in our educational system and is largely accepted by national mainstream media. It is plausible, then, that both groups expect that a journalist writing an op-ed piece in USA Today will tend to represent the pro-evolution perspective and that NCSE members will consider this only fair. This status difference may also explain why pro-evolution individuals evaluated the pro-evolution source no differently than the journalist source. For Discovery Institute members, an ingroup source lessened their expectations, relative to the “neutral” journalist source, that the story would be hostile to their view, but for NCSE members no such hostile expectation existed to begin with. Hence, the effect of an ingroup source is to make otherwise defensive readers approach article content with a more open mind. An outgroup source, on the other hand, gives DI and NCSE members alike a reason to be defensive. These findings suggest that a source-based defensive mechanism may play an important role in biased evaluations, at least when content differences are held constant.

Overall, these results suggest that how message content fits with an individual’s pre-existing opinion, and how message source resonates with an individual’s group affiliation, will both affect how that message is evaluated.

(Last Updated: September 9, 2013)

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