The modern citizen lives in a sea of words. The daily newspaper includes thousands of words to attract interest. Television news adds pictures and color, but requires accompanying spoken words to be enlightening. Increasingly, headlines, news stories, telecasts, magazine articles, and instruction manuals use a vocabulary of scientific terms and concepts, often assuming that most readers or viewers will understand them. This section looks at the level of public understanding of science and technology concepts.
An understanding of a basic set of scientific concepts is an important prerequisite for understanding discussions of science and technology, and for participating in the process of formulating science and technology policy. While the range of possible scientific terms or concepts is large, it is possible to identify a sample of items that concern the composition of matter, the nature of the universe, the basic processes that have shaped our planet, and the basic biology that supports life. A set of nine knowledge items can be used to estimate the level of scientific construct understanding in the United States over the last decade.
Looking at the level of understanding on the individual items, it appears that only 11 percent of Americans can define the term "molecule." (See figure 7-6 and appendix table 7-9.) A large proportion of the population knows that a molecule is a small piece of matter, but is unable to relate it to an atom or a cell, which are also small pieces of matter. One in five Americans was able to provide a minimally acceptable definition of DNA. And, despite substantial media attention to deep space probes and pictures from the Hubble Space Telescope, only 48 percent of Americans know that the earth goes around the sun once each year.
On the positive side, 78 percent of Americans recognize that portions of the earth's crust-thought of in terms of continents-have been moving for millions of years and will continue to move in the future, and 75 percent know that light travels faster than sound. About 71 percent of American adults reject the idea that all radioactivity is man-made. Despite this promising level of understanding of these basic physical and geological concepts, only 39 percent of American adults disagreed with the statement that "lasers work by focusing sound- waves." Perhaps reflecting the legacy of Fred Flintstone, only half of Americans rejected the statement that "the earliest humans lived at the same time as the dinosaurs."
Using the same testing technology used in many national and international tests, the responses to these nine items were converted into a 0-100 scale. The mean score for American adults on the Index of Scientific Construct Understanding was 55, the same as in 1995 and comparable to 1988 and 1990 index scores. (See figures 7-7 and 7-8 and appendix table 7-10.) Understanding of scientific constructs was strongly related to both the level of formal education and the number of high school and college science and mathematics courses taken. The mean score for college graduates was 68, compared to 44 for individuals who did not complete high school. Individuals who completed nine or more high school and college science or math courses had a mean score of 74, compared to 47 for adults who had five or fewer courses.
Men scored significantly higher than women, with a mean score of 62 compared to 49 for women. (See figure 7-7 and appendix table 7-10.) The scores partly reflect differences in coursetaking patterns, with men traditionally taking more science and mathematics courses than women. Several studies from the last decade indicate that this coursetaking gap has been nearly eliminated in mathematics and in science.
To handle the daily flow of news reports about scientific and medical findings, citizens must understand the nature of scientific inquiry. A major difficulty in measuring the public understanding of scientific inquiry is that science does not utilize a single uniform procedure. While some sciences rely heavily on experimental procedures, others depend primarily on observation, measurement, and model building and testing. Other sciences depend heavily on fossil discovery, classification, and the construction or integration of possible developmental sequences. Virtually all of these approaches are utilized to some degree under the broad umbrella of scientific inquiry.
What is central to all scientific endeavor, however, is the effort to build theories or models to enhance our understanding of nature and the materials and processes found in nature. Parallel to the theory-building process is a commitment that all theories must be subject to logical or empirical falsification. Thus, the first level of conceptualization of science is an activity for the purpose of building and testing theory.
At a second level, some individuals think of all scientific inquiry as a form of experimental investigation. This may reflect an understanding that scientific ideas are subject to testing. Popper's concept of falsification is not widely known (Popper 1959), and most people still think that scientists prove their theories or ideas much as a mathematician might "prove" a theorem. Thus, a second important level of public understanding of scientific inquiry involves the view of science as the conduct of experimentation. This view is reinforced by frequent media reports of medical and pharmaceutical trials of new procedures or products.
At a third level, some people simply think of science as rigorous comparison. This view of science is largely devoid of any notion of theory building. It lacks understanding of experimentation as the use of random assignment and control groups, or of the purposes for those procedures. It does view science as empirical in character, often perceiving science as "testing," as against some known standard.
Below these levels of conceptualization, many individuals have some awareness of the word "science," but no cognitive substance behind the word. It may be associated with precise measurement or with good or bad outcomes (medical miracles or weapons of mass destruction), but the work of scientists and the process of scientific inquiry are not understood. Most of these individuals hold positive attitudes toward science, and expect it to cure most diseases and to solve environmental problems. There is, however, a higher level of reservation among these individuals, which may reflect their recognition of the enormous power of science and technology and their inability to understand it.
To find out how well the public understands the nature of scientific inquiry, adults have been surveyed in a series of Science & Engineering Indicators studies over the last decade. They were asked to define the meaning of scientific study, and their responses have been recorded and coded. In 1995 and 1997, each respondent was asked the same open-ended question about scientific study and given a set of questions concerning an experimental evaluation of a drug. They were also asked a set of questions concerning the meaning of probability, using an example of an inherited illness. Each respondent was classified, using a combination of these responses, as having or not having at least a minimal level of understanding of the nature of scientific inquiry. In 1997, approximately 27 percent of American adults met the standard of having a minimal understanding of the nature of scientific inquiry, continuing a gradual increase over the last decade. (See figure 7-9 and appendix table 7-11.)
It is possible to obtain a sense of international commonalties and differences by comparing the mean scores on the Index of Scientific Construct Understanding for 14 of the leading industrial nations. Using the 100-point index described above, the United States, Denmark, the Netherlands, and Great Britain all produced mean scores of between 53 and 55. (See figure 7-10 and appendix table 7-12.) Although the years in which the data were collected from the other countries range from 1989 to 1992, the provision of the three time periods for the United States illustrates the stability of the U.S. estimate; there is no basis for assuming a more rapid change in other major industrial nations.
The results of the Third International Mathematics and Science Study (TIMSS) are relevant to this discussion since they showed that students in the United States ranked in the middle range of industrial countries. (See chapter
1.) There are a number of plausible reasons why American adults may score ahead of, or equal to, adults in other industrial nations. First, a higher percentage of U.S. youth have enrolled in postsecondary schooling for most of the last five
decades. A second possible reason is that there has been and continues to be a more pervasive use of general education requirements in the United States, which include one or more years of college-level science instruction for all college students,
regardless of degree or career objective. In Europe and Japan, fewer youth enroll in college or university, and postsecondary students who do not plan a career in science or related fields are not required to take college-level science or mathematics
courses. It is also possible that college-level science instruction in the United States is enhanced by informal science learning resources. These include zoos, aquariums, museums, science television programs, science magazines, public libraries, and
the World Wide Web. Other reasons are based in the methodologies of these studies. The ability of TIMSS performance to predict a student's adult knowledge has not been established. Different testing instruments and procedures can lead to substantial
differences in results. The factors associated with these differences merit further study.
This duality of meaning creates an interesting measurement problem. When a respondent is asked, for example, what it means to study something scientifically, and responds that it has to do with "making theories and things," it is not clear whether the individual means to use theory in a Kuhnian (Kuhn 1962) sense or as an unsupported speculation. For this reason, it is important to ask these questions in an open-ended format and to probe the responses.
"When you read news stories, you see certain sets of words and terms. We are interested in how many people recognize certain kinds of terms, and I would like to ask you a few brief questions in that regard. First, some articles refer to the results of a scientific study. When you read or hear the term scientific study, do you have a clear understanding of what it means, a general sense of what it means, or little understanding of what it means?"
If response is "clear understanding" or "general sense": "In your own words, could you tell me what it means to study something scientifically?"
In addition, each respondent was asked the following question:
"Now, please think of this situation. Two scientists want to know if a certain drug is effective against high blood pressure. The first scientist wants to give the drug to 1,000 people with high blood pressure and see how many experience lower blood pressure levels. The second scientist wants to give the drug to 500 people with high blood pressure, and not give the drug to another 500 people with high blood pressure, and see how many in both groups experience lower blood pressure levels. Which is the better way to test this drug? Why is it better to test the drug this way?"