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Selectivity of Sources: Reporting the Marijuana Controversy

by R. Gordon Shepherd

Journal of Communication Spring 1981 p129-137

R. Gordon Shepherd is in the Department of Sociology, University of Central Arkansas. An earlier version of this article was presented at the Science Writing Education Group session at the meeting of the Association for Education in Journalism, Boston, August 10, 1980, which was partially funded by the Gannett Foundation, with additional support from Science, Technology, and Human Values, Technology Review, and the MIT Programs in Science Writing and in Science, Technology, and Society. findings summarized here were first reported in (11).

The press appears to rely primarily on a few "science celebrities, rather than specialists conducting relevant research, for their scientific information.

We live in a world in which we must increasingly rely on the knowledge of specialists and the advice of experts. This is a basic correlate of the division of labor in society. The problem for non-experts faced with complex, technical questions is how to access necessary, often times esoteric information which they must have to make decisions. This problem is compounded by the fact that specialists or expert sources do not always agree. Thus, those who seek information must not only "know" who the appropriate experts are, but also be prepared to weigh the credibility of conflicting interpretations when experts disagree (see 1, p. 78).

The task of accessing and converting expert knowledge into social action is a particularly crucial one in democratic systems. A functioning democratic order presupposes the participation of informed lay publics which, in turn, implies a certain degree of "equivalent enlightenment as between expert, leader and laymen," to borrow Lasswell's phrase (9, p. 188). Political leaders typically have direct access to experts; the access of lay publics to experts, however, is typically indirect and most commonly occurs through the agency of the mass media. The popularization and diffusion of expert knowledge in a form intelligible to non-experts must be recognized as a major function of the mass media in a democratic society.

No expert is more esteemed today than the scientist. Commitment to the value of problem-solving through the use of scientific method has become a fundamental aspect of secular consciousness. When we wish to know the "facts" about any empirical phenomenon, it is the scientist to whom we turn for information. Above all, what is of most interest to non-scientists about science are the implications of scientific knowledge "for human life, or its applications, if any, to the solution of human problems" (11, p. 3). Though, in point of fact, a large fraction of scientific research and theory construction does not appear directly aimed at treating problems posed by immediate social needs (see 7), scientists are expected to provide authoritative information and expertise relevant to all kinds of mundane concerns. In the layperson's view (if not that of scientists themselves) the most importantly value of science lies in its utilitarian consequences; that is, the primary function of science is popularly seen as its ability to stimulate technological solutions to complex problems of practical import. It is this promise which, in a secular age, makes scientists so highly valued as experts and their craft a newsworthy subject.

The application of scientific knowledge to human problems is not, of course, simply a technical matter; it is fundamentally ideological.

Which problems are given priority, which goals are deemed worth seeking, and which policies of implementation are to be followed are always defined from the vantage point of a particular value system, cultural perspective, or location within the social order. These are ideological and political questions and are ultimately determined by the structure of political power. The scientific ideals of value neutrality and pursuit of knowledge for its own sake make it possible for scientists to disavow direct responsibility for these types of decisions or for the potential uses to which their discoveries may be put by others.

Nonetheless, scientific views have come to play an important role in the conduct of contemporary ideological struggles. Secular consciousness dictates that political efforts be buttressed by a "rationally justifiable system of ideas" or world-view rather than a dogmatic or "frank enunciation of their creed" (10, p. 32), as in pre-modern times. The modern political groups attempt to incorporate " rational and if possible scientific arguments into their system of thought" (10, p. 32). Partisan assertions as to the proper resolution of various social issues must not appear arbitrary or self-serving, but supported by empirical evidence. Much public debate of political and social issues is characterized by effort on the part of all conflicting parties to marshal scientific evidence which is both supportive of their own views and damaging to the credibility of others. In the words of one observer, "nothing has greater discrediting [or legitimizing power today than the demonstration that a given assertion has been 'scientifically disproven' [or proven]. Our contemporary pawnbrokers of reality are scientists" (6, p. 56).

The ideological value of science lies in its great prestige as an arbiter of what is true and what is false, of what is real and what is not real. Though scientists personally may attempt to divorce their work from political causes, the findings of science are exploitable by various interest groups [including perhaps most conspicuously, government agencies) who hope to use them for legitimating their own social policy preferences. At the same time, scientists may actively espouse their views in support of various causes or, as experts, give counsel to those promoting ones with which they sympathize. In the latter case, it is not uncommon for a scientific community to be divided as to the practical meanings of its discoveries, or to the uses to which they should be put. Thus many social controversies are characterized by scientific advocacy on opposing sides of an issue. The ideological pluralism of the scientific community over social issues becomes itself newsworthy, an item on which the press has shown a growing tendency to report in recent years (see 11, pp. 3-4.).

How well do the media function in popularizing and disseminating views of scientific authorities on controversial subjects?

lay publics are sensitized to scientifically controversial issues through the mass media. Research findings are reported; scientists are interviewed, their opinions are solicited and quoted by reporters; their pronouncements are publicized. Much of what most people in Western society know or think they know about science-related issues, they have learned through newspapers, magazines, or television.

The familiar problems of accuracy and selectivity common to the objective reporting of all kinds of news are magnified in the case of science news. Most areas of scientific discourse have long since become so technical as to be unintelligible to non-scientists. The translation of scientific work and its implications for lay audiences involve great potential for sheer inaccuracy through reporters' inability to interpret their subject correctly , or their propensity to oversimplify, or both. News distortion or "refraction" (8, p.438) produced through selectivity is, if anything, potentially even more serious. As with all forms of journalism, the initial decision of what to report, which "facts" to attend to and emphasize and which to leave out, is undoubtedly the single most important act in science news reporting.

In any given area of scientific research, hundreds of studies may be conducted by thousands of scientific investigators. But only a small fraction of these will gain the attention of the mass media and, hence, the attention of a mass audience. Which scientific findings do the media select to publicize and which not? Which scientists are selected by the press as representative "experts" and "authorities" in their field and which not? Of crucial relevance to the selection of scientific sources are the sources' scientific credentials. Are the most credible sources the ones which tend to be selected most?

It is important to recognize that within any scientific community there exists a system of ranking or social stratification in terms of which both the quality of scientific work and individual expertise are differentiated (see 4). Lay publics, however, are seldom sensitized to the standards of expertise and quality which distinguish within a community of experts. For the person in the street, the necessary credentials for validating the respectability and authority of scientific claims are apt to be fairly crude. It often suffices to simply learn that such and such a finding has been produced in a "laboratory" or uncovered in "scientific research," or that the authority referred to is a "scientist," chemist, biologist, psychiatrist, M.D., Ph. D., and so on, whose actual scientific repute is not easily discernable to lay observers.

To what extent are the media sensitive to actual scientific standing or credibility of those sources on which they choose to report? To what extent does the attribution of scientific prominence by the media coincide with the attribution of prominence by scientists themselves? This is an important issue, since the mass media's representations of scientifically credible sources are bound to shape public perception of science-related issues regardless of what their actual status might be in the scientific community.

To explore the media's selection of scientific sources I chose to study a specific science news context, namely, the marijuana controversy.

The issue of marijuana serves as a good case in point because interpretation of its use has become both a heated moral and scientific issue, should the recreational use of marijuana be legally tolerated or not? People's attitudes toward the legal status of marijuana are probably shaped by their "knowledge" of its personal and social consequences. Is marijuana really a dangerous drug? If so, how dangerous? Is it "addicting?" Does it really "lead to" the use of other drugs? Can it cause lasting physical and/or psychological impairment? does its use promote crime and violence? Or, conversely, is it a relatively innocuous euphoriant, the moderate use of which entails few personal or social risks? These are empirical scientific questions which can and have been investigated by researchers in recent years.

Legal positions taken on the marijuana issue are made appealing to the degree that they are supported by scientific evidence on the psycho-active character of marijuana. If it is scientifically demonstrated that marijuana is harmful to the individual or socially dangerous, the argument that it ought not be used, or that society ought to suppress its use, makes rational sense and is likely to gain public support. if, however, it is scientifically demonstrated that marijuana is not a particularly harmful substance, proscriptive arguments make less sense and would be less likely to attract public support.

Thus marijuana as a social issue cannot be divorced from marijuana as a scientific question. it is precisely the kind of issue for which the public seeks scientific testimony. At the same time, the moral and political controversies surrounding the marijuana issue have been paralleled by apparent scientific controversy. Some scientists and medical authorities have affirmed a number of serious pathologies associated with the recreational use of marijuana and have viewed it as a public health problem of the first magnitude. Other authorities have reported that marijuana is a remarkably nontoxic drug whose evils are largely mythical, and seem convinced that its use is much less harmful than that of other socially sanctioned drugs, such as alcohol and tobacco. The scientific literature on marijuana over the past decade and a half is rife with contradictory studies and conclusions.

How have the mass media managed the reporting of this controversy? In particular, which scientific sources on marijuana have been given the greatest media attention and what is the scientific credibility of those sources within the research community of marijuana investigators?

To test these questions we need, among other things, a measure of scientific repute or credibility.

The method of science citation counts was employed in this study as the most reliable quantified measure of scientific standing available (see 2, 3, 5). The logic behind citation counts is simple: if a particular piece of scientific research is highly regarded within a scientific community it will be referenced and used in the writings of other scientists working on similar problems. If a particular scientist's work is esteemed by colleagues, his or her research will have been widely circulated and cited in others' research. thus the greater the number of citations, the greater the influence or repute a particular study or scientist may be assumed to enjoy within scientific circles.

Accessing citation data for both specific studies and the careers of individual scientists is made possible through Science Citation Index, a yearly reference work which publishes both author and subject index (see 2, 3 5). An extensive review of the scientific literature on marijuana for the years 1967-72 was conducted and citation counts were done for 245 science journal articles on marijuana and for 196 authors, or "marijuana authorities." This served to establish the citation norms for scientific research on marijuana and to identify which studies and which investigators have been most influential among other scientists. Over this particular time period the most frequently cited study in the marijuana literature had a yearly mean of 31.6 citations, while the average number of citations to all studies surveyed was 3.4; the most frequently cited marijuana researcher had a total of 251 citations to all of his work on marijuana published during the period 1967-72, while the median number of marijuana citations for all researchers sampled was 6.9.

Next, a survey of science news articles on marijuana was taken from a sample of newspapers and magazines for the purpose of evaluating the press's selectivity of credible scientific sources. A science news article was any article which made statements about marijuana attributed to a scientific source. The newspapers sampled were three large metropolitan dailies: the New Your Daily News, the New York Times, and the Chicago Tribune. These papers were chosen as the first, third and fourth largest circulation dailies in the U.S., respectively, and as representing putatively different ideological and stylist journal types (the "sensationalistic" tabloid, the liberal "Eastern establishment" paper, and the "middle America" conservative daily). Magazines sampled included three news magazines (Time, Newsweek, and U.S. News and World Report ), ten "family" magazines (e.g. Life, McCalls, Reader's Digest ), eight opinion and commentary magazines (Saturday Review, Atlantic Monthly, National Review, etc. ), and five health/science magazines (Scientific American, Today's health, Popular Science, etc.). Wire service and other repetitions were counted every time they appeared; if a science article of any length or location appeared in any popular source sampled it was counted, regardless of how many times it might have been reported in other sources.

Of 275 science news articles surveyed, only 59 cited the results of only 20 marijuana research publications. thus, despite marijuana's highly topical nature, scientific studies of marijuana received very little attention in the popular press. However, the scientific credibility of those 20 studies does appear to be quite high. The two most frequently cited research reports in the scientific literature, for instance, were also the two studies most frequently cited by the press. In general, studies that were cited by the press had relatively high citation frequencies within scientific circles: the mean numbers of annual scientific citations of those marijuana studies cited by the popular press was roughly five times the number of citations of those that were not cited (15.7 vs 2.8).

If the treatment of marijuana can be taken as representative of the treatment of other science issues, it appears that the press tends to print the views and interpretations of individual authorities rather than report the results of actual studies. Over three-quarters (77 percent) of the 275 science news stories sampled failed to cite any specific marijuana studies, but rather used statements made by various authorities to whom expert scientific or medical credentials were imputed.

Over two-thirds (69 percent) of those represented by the press as science authorities had no citations to any work on marijuana published in science journals as ascertained by examining the Index Medicus; the great majority had, in fact, never done any research on marijuana at all. There were, of course, some genuine marijuana experts represented, but the median citation count to the scientific work on marijuana conducted by all of the media attributed authorities was practically nil (0.2) and there was little apparent relation between one's appearance as an authoritative spokesman in the press and one's standing among experienced marijuana researchers.

Who, then, if not marijuana researchers, does get the lion's share of the media's attention as marijuana authorities? Seven of ten authorities most frequently cited by the popular press were administrative officials of such government institutions as the National Institute of Mental health, the Food and Drug Administration, the Department of Health, Education and Welfare, or of private medical establishments. These individuals have credentials such as M.D.s or Ph.D.s, but have devoted themselves full-time to administrative concerns and are not personally active at the forefront of research in their fields, let alone expert in a special topic area like marijuana use.

In addition to health-science administrators, highly prominent scientists in fields tangentially related to marijuana research also seem to attract media attention. Thus, Nobel Prize winners in medicine, chemistry, or biology, or world famous anthropologists, psychiatrists, or pediatricians may become celebrities, whose personal opinions are used on a whole host of issues, including marijuana. That the press tends to devote attention to authorities who‹‹although not themselves marijuana researchers‹‹are prominent scientists in other areas is confirmed by another reading of the citation data: the median number of citation counts to the entire corpus of scientific work (regardless of topic area) done by media-publicized authorities (those sources to whom the press attributed scientific credentials and whose statements constituted a science news article) was an impressively high 38.9. this may be compared to the meager citation count mentioned previously of only 0.2 to their marijuana-related research.

Of course, in focusing on the credentials of those sources to whom the media attribute expertise, I have neglected to investigate the typical journalistic procedures for obtaining information on scientific views and findings, i.e., the actual practices followed for maintaining contact with scientific communities. Numerous studies have been done on the way in which events defined as news and on the process through which they come to be reported as news items, but few, if any, have paid much attention to how the media go about getting information on science related issues. It can be assumed that a sizable fraction of science news items are generated for the press by various interest groups, both government and private, who seek to "make news" by calling press conferences, releasing findings, and making public pronouncements. This is most likely to be the case when a "breakthrough" study or "crucial experiment" in a significant area has apparently been achieved, and is especially likely to occur when interest groups are anxious to legitimate social policy preferences.

In generalizing beyond this particular case, a number of questions may be raised that involve both theoretical and value issues.

Does it make any difference if the mass media are sensitive or not to the technical scientific credentials of their sources? Are the media responsible for weighing and evaluating expert credentials as part of the news selection process? For that matter, how is science news gathered and processed? How do the media actually go about selecting scientific sources and how, if we lived in the best of all possible worlds, ought they to do so (or, at least, how might current practices be improved)?

The answers to these questions depend very much on one's conceptions of the proper function of the press in society. Assuming democratic values in a secular age of mass society, the promotion of "equivalent enlightenment" becomes a primary function of the press, as already argued. Such an achievement must obviously be regarded as an ideal or working goal, departures from which, in practice, are also anticipated. However, professional vigilance can be maintained to minimize such departures. It is not, of course, the task of journalists to judge the ultimate validity of expert or scientific knowledge regarding scientific questions. But it is their task to seek out, insofar as they are able, genuinely expert sources. This may mean going beyond those sources which ar most immediately visible, such as directors and administrators of prominent government and private agencies, or a few "celebrity" sages who are presumed to know something about practically everything.

To the extent that the media presume responsibility for the independent investigation of science-related issues, there needs to be greater care given to the expert credentials of individual authorities. Greater effort is required to contact those students and scholars actually engaged at the cutting edge of research in their specialized areas. To ferret out such sources who, in many instances, may be publicly invisible, will require preliminary searching, perhaps, as here, by examining topical science indexes, such as Index Medicus and Science Citation index.

Does it make a difference? Reporters pride themselves on "going to the source," whatever that source might be. If they write a story on the performance of athletes on the playing field, their first informants will be athletes themselves‹‹not their coaches, managers, and not the club owners. If their editor calls for a piece on the state of the art of the novel, statements by Saul Bellow and Lord Snow will immediately spring to mind, not their agents or publishers (see 12). And if mass publics are to be informed of scientific evidence bearing on controversial issues, who better to query than those specialists whose own research has won them recognition of their scientific peers?


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3. Cole, Steven and Jonathan Cole. "Visibility and the Structural bases of Awareness of Scientific Research." American Sociological Review 33, 1968, pp. 397-413.

4. Cole, Steven and Jonathan Cole. Social stratification in Science. Chicago: University of Chicago Press, 1973.

5. Garfield, Eugene. "Citation analysis as a Tool in Journal Evaluation." Science 178, 1972, pp. 471-479.

6. Goode, Erich, The Marijuana Smokers. New York: Basic Books, 1970.

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12. Shepherd, R. Gordon and Erich Goode. "Scientists in the Popular Press." New Scientist 76(1079), November 1977.