If a set of 10 items from the 1995 Science and Engineering Indicators study is considered, results show a wide range of understanding of these concepts, from 0 correct to 9 correct, with a mean of 5.2. (See figure 7-6.) Approximately 27 percent of American adults provided correct responses to 7 or more of the 10 items. This scale is useful because two of the items were open-ended, requiring the respondent to provide a response rather than select among the alternatives as in a multiple choice or true-false question.
If the level of understanding on individual items is considered, fewer than 1 in 10 Americans can explain a molecule. A large portion 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. (See figure 7-7 and appendix table 7-7.) Despite the use and public discussion of DNA in widely publicized court trials and dramatic television shows, only one in five Americans can provide a minimally acceptable definition of DNA. And, despite substantial media attention to deep space probes and pictures from the Hubble telescope, only 49 percent of Americans know that the Earth rotates around the Sun once each year.
On the positive side, 85 percent of Americans recognize that oxygen comes from plants, and nearly 80 percent of them know that the center of the Earth is very hot and 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. Despite this promising level of understanding of these basic biological and geological concepts, less than half of American adults agree that human beings evolved from earlier species and developed millions of years after the death of the dinosaurs. Many Americans appear to hold a mix of correct and incorrect scientific understandings that are not integrated into any broader level of systemic understanding.
The level of understanding of basic scientific terms and concepts is closely associated with the number of years of formal schooling completed and the number of science and mathematics courses taken. (See figure 7-8 and appendix table 7-8.) Those Americans who are attentive to science and technology policy issues displayed a higher level of understanding of these basic terms and concepts - a mean score of 6.4 - than other citizens.
What is central to all scientific endeavors, however, is the process of building theories or models that enhance our understanding of nature (Kuhn, 1962). Parallel to this process is a commitment that all theories 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.3
At a second level, some individuals think of all scientific inquiry as a form of experimental investigation. To an extent, this may reflect a basic understanding of scientific ideas as being subject to testing. Popper's concept of falsification (Popper, 1959) is not widely known, and most people still think that scientists prove their theories or ideas as a mathematician might "prove" a theorem. In this context, a second important level of public understanding of scientific inquiry involves viewing science as the conduct of experimentation. The frequent media reporting on medical and pharmaceutical trials of new procedures and products reinforces this view.
At a third level, science is viewed as a combination of rigorous comparison and precise measurement. This view is largely devoid of any notion of theory building. Most often, this view lacks any understanding of experimentation as the use of random assignment and control groups and any appreciation of the purposes for those procedures. This view does see science as empirical in character and precise in its measurements, often resulting in a view of science as "testing," as against some standard. It is not a very sophisticated view, but most individuals holding this view would have greater confidence in a product that was "tested scientifically" than one that was not.
Below these levels of conceptualization, many individuals have some awareness of the word science, but generally have no cognitive substance behind the word. It may be associated with good or bad outcomes (medical miracles or weapons of mass destruction), but the work of scientists and the process of scientific inquiry are black boxes, at best. Generally, most individuals with this level of understanding have positive attitudes toward science, and expect it to cure virtually every disease and ailment and to solve any environmental problem. However, there is a wariness that appears to flow from recognizing the enormous power of science and technology and the individual's almost total lack of understanding of it.
In order to examine the level of public understanding of the nature of scientific inquiry, national surveys asking adults to define the meaning of scientific study have been conducted and reported in a series of Science and Engineering Indicators Public Attitudes and Understanding surveys. In the 1995 Science and Engineering Indicators study, each respondent was asked the same open-ended question as in previous studies as well as a new set of questions concerning the experimental evaluation of a drug.4 Through each individual's response, a new typology of the understanding of scientific inquiry was constructed. Each respondent of the 1995 Indicators study was classified into one of the four following levels of understanding:
The number of years of formal schooling and the number of science and mathematics courses taken are closely associated with an individual's level of understanding of the nature of scientific inquiry. While fewer than 1 percent of respondents with less than a high school diploma were able to define the purpose of science as theory building or testing, 10 percent of graduate degree holders defined scientific inquiry in that manner. (See figure 7-10 and appendix table 7-9.) If responses that characterized science in terms of theory building or experimentation are combined, only 4 percent of Americans who had not completed high school were able to provide a minimally acceptable response, compared with 50 percent of those with baccalaureate degrees and 59 percent of those with graduate and professional degrees. Similarly, only 9 percent of individuals with a low level of formal science and mathematics coursework were able to provide an acceptable definition of scientific inquiry, compared with 52 percent of individuals with nine or more science and mathematics courses in high school and college. Clearly, education makes a difference in understanding the purpose of science and the nature of scientific inquiry.
3 While there is broad consensus that theory building is the primary objective of science, this level of conceptualization is relatively rare in the public and not universal among graduates of science, engineering, or medical programs. The measurement of the understanding of scientific inquiry at this level is compounded by the dual meaning of theory in American English. In the usage employed in the preceding paragraph, we mean theory to refer to comprehensive sets of statements about the operation of various aspects of nature, or the development of models of natural processes. This usage would apply to generalizations or models in the biological, social, or physical sciences. At the same time, theory is often used in everyday language to refer to speculations or suppositions not yet supported by evidence. For example, it is common to hear a person dismiss a speculation by another person by saying that it is "only a theory," meaning that there is no evidence, or insufficient evidence, for that conclusion. Ironically, this is almost exactly the opposite meaning of the term as used in science.
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 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.
4 The question on the meaning of scientific study was, "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 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?"
As a part of the same interview, each respondent was asked a series of questions that included previously asked items about lucky numbers and whether or not astrology is very scientific, sort of scientific, or not at all scientific.