When some people think of science, they think of formulas and facts to memorize. Many of us probably studied for a test in a science class by memorizing the names of the four nucleotides in DNA (adenine, cytosine, guanine, and thymine) or by practicing with one of Newton's laws of motion, like f = ma (force equals mass times acceleration). While this knowledge is an important part of science, it is not all of science. In addition to a body of knowledge that includes formulas and facts, science is a practice by which we pursue answers to questions that can be approached scientifically. This practice is referred to collectively as scientific research, and while the techniques that scientists use to conduct research may differ between disciplines, the underlying principles and objectives are similar. Whether you are talking about biology, chemistry, geology, physics, or any other scientific field, the body of knowledge that is built through these disciplines is based on the collection of data that are then analyzed and interpreted in light of other research findings. How do we know about adenine, cytosine, guanine, and thymine? These were not revealed by chance, but through the work of many scientists collecting data, evaluating the results, and putting together a comprehensive theory that explained their observations. Show
A brief history of scientific practiceThe recorded roots of formal scientific research lie in the collective work of a number of individuals in ancient Greek, Persian, Arab, Indian, Chinese, and European cultures, rather than from a single person or event. The Greek mathematician Pythagoras is regarded as the first person to promote a scientific hypothesis when, based on his descriptive study of the movement of stars in the sky in the 5th century BCE, he proposed that the Earth was round. The Indian mathematician and astronomer Aryabhata used descriptive records regarding the movement of objects in the night sky to propose in the 6th century CE that the sun was the center of the solar system. In the 9th century, Chinese alchemists invented gunpowder while performing experiments attempting to make gold from other substances. And the Middle Eastern scientist Alhazen is credited with devising the concept of the scientific experiment while researching properties related to vision and light around 1000 CE. These and other events demonstrate that a scientific approach to addressing questions about the natural world has long been present in many cultures. The roots of modern scientific research methods, however, are considered by many historians to lie in the Scientific Revolution that occurred in Europe in the 16th and 17th centuries. Most historians cite the beginning of the Scientific Revolution as the publication of De Revolutionibus Orbium Coelestium (On the Revolutions of the Heavenly Spheres) in 1543 by the Polish astronomer Nicolaus Copernicus. Copernicus's careful observation and description of the movement of planets in relation to the Earth led him to hypothesize that the sun was the center of the solar system and the planets revolved around the sun in progressively larger orbits in the following order: Mercury, Venus, Earth, Mars, Jupiter, and Saturn (Figure 1). Though Copernicus was not the first person to propose a heliocentric view of the solar system, his systematic gathering of data provided a rigorous argument that challenged the commonly held belief that Earth was the center of the universe. Figure 1: The front cover and an inner page from De Revolutionibus showing Copernicus's hypothesis regarding the revolution of planets around the sun (from the 2nd edition, Basel, 1566). (from http://www.webexhibits.org/calendars/year-text-Copernicus.html)The Scientific Revolution was subsequently fueled by the work of Galileo Galilei, Johannes Kepler, Isaac Newton (Figure 2), and others, who not only challenged the traditional geocentric view of the universe, but explicitly rejected the older philosophical approaches to natural science popularized by Aristotle. A key event marking the rejection of the philosophical method was the publication of Novum Organum: New Directions Concerning the Interpretation of Nature by Francis Bacon in 1620. Bacon was not a scientist, but rather an English philosopher and essayist, and Novum is a work on logic. In it, Bacon presented an inductive method of reasoning that he argued was superior to the philosophical approach of Aristotle. The Baconian method involved a repeating cycle of observation, hypothesis, experimentation, and the need for independent verification. Bacon's work championed a method that was objective, logical, and empirical and provided a basis for the development of scientific research methodology. Figure 2: Sir Isaac NewtonBacon's method of scientific reasoning was further refined by the publication of Philosophiæ Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy) by the English physicist and mathematician Isaac Newton in 1686. Principia established four rules (described in more detail here) that have become the basis of modern approaches to science. In brief, Newton's rules proposed that the simplest explanation of natural phenomena is often the best, countering the practice that was common in his day of assigning complicated explanations derived from belief systems, the occult, and observations of natural events. And Principia maintained that special explanations of new data should not be used when a reasonable explanation already exists, specifically criticizing the tendency of many of Newton's contemporaries to embellish the significance of their findings with exotic new explanations. Bacon and Newton laid the foundation that has been built upon by modern scientists and researchers in developing a rigorous methodology for investigating natural phenomena. In particular, the English statisticians Karl Pearson and Ronald Fisher significantly refined scientific research in the 20th century by developing statistical techniques for data analysis and research design (see our Statistics in Science module). And the practice of science continues to evolve today, as new tools and technologies become available and our knowledge about the natural world grows. The practice of science is commonly misrepresented as a simple, four- or five-step path to answering a scientific question, called "The Scientific Method." In reality, scientists rarely follow such a straightforward path through their research. Instead, scientific research includes many possible paths, not all of which lead to unequivocal answers. The real scientific method, or practice of science, is much more dynamic and interesting. Comprehension Checkpoint Scientific research, if done correctly, follows a straightforward five-step path and leads to definite answers. More than one Scientific MethodThe typical presentation of the Scientific Method (Figure 3) suggests that scientific research follows a linear path, proceeding from a question through observation, hypothesis formation, experimentation, and finally producing results and a conclusion. However, scientific research does not always proceed linearly. For example, prior to the mid 1800s, a popular scientific hypothesis held that maggots and microorganisms could be spontaneously generated from the inherent life-force that existed in some foods. Louis Pasteur doubted this hypothesis, and this led him to conduct a series of experiments that would eventually disprove the theory of spontaneous generation (see our Experimentation in Scientific Research module). Pasteur's work would be difficult to characterize using Figure 3 – while it did involve experimentation, he did not develop a hypothesis prior to his experiments. Instead he was motivated to disprove an existing hypothesis. Or consider the work of Grove Karl Gilbert, who conducted research on the Henry Mountains in Utah in the late 1800s (see our Description in Scientific Research module). Gilbert was not drawn to the area by a pressing scientific question, but rather he was sent there by the US government to explore the region. Further, Gilbert did not perform a single experiment in the Henry Mountains; his work was based solely on observation and description, yet no one would dispute that Gilbert was practicing science. The traditional and simplistic Scientific Method presented in Figure 3 does not begin to reflect the richness or diversity of scientific research, let alone the diversity of scientists themselves. Figure 3: The classic view of The Scientific Method is misleading in its representation of scientific practice.Scientific research methodsScientific research is a robust and dynamic practice that employs multiple methods toward investigating phenomena, including experimentation, description, comparison, and modeling. Though these methods are described separately both here and in more detail in subsequent modules, many of these methods overlap or are used in combination. For example, when NASA scientists purposefully slammed a 370 kg spacecraft named Deep Impact into a passing comet in 2005, the study had some aspects of descriptive research and some aspects of experimental research (see our Experimentation in Scientific Research module). Many scientific investigations largely employ one method, but different methods may be combined in a single study, or a single study may have characteristics of more than one method. The choice of which research method to use is personal and depends on the experiences of the scientists conducting the research and the nature of the question they are seeking to address. Despite the overlap and interconnectedness of these research methods, it is useful to discuss them separately to understand the principal characteristics of each and the ways they can be used to investigate a question.
These methods are interconnected and are often used in combination to fully understand complex phenomenon. Modeling and experimentation are ways of simplifying systems toward understanding causality and future events. However, both rely on assumptions and knowledge of existing systems that can be provided by descriptive studies or other experiments. Description and comparison are used to understand existing systems and are used to examine the application of experimental and modeling results in real-world systems. Results from descriptive and comparative studies are often used to confirm causal relationships identified by models and experiments. While some questions lend themselves to one or another strategy due to the scope or nature of the problem under investigation, most areas of scientific research employ all of these methods as a means of complementing one another toward clarifying a specific hypothesis, theory, or idea in science. Comprehension Checkpoint Scientific research methods, such as experimentation, description, comparison, and modeling, Research methods in practice: The investigation of stratospheric ozone depletionScientific theories are clarified and strengthened through the collection of data from more than one method that generate multiple lines of evidence. Take, for example, the various research methods used to investigate what came to be known as the "ozone hole." Figure 4: A picture of the Antarctic Ozone Hole in 2000, one of the largest holes on record. Ozone levels are given in Dobson Units, a measurement specific to stratospheric ozone research and named in honor of G.M.B. Dobson, one of the first scientists to investigate atmospheric ozone. For more information see http://toms.gsfc.nasa.gov/teacher/basics/dobson.html. image © TOMS science team & and the Scientific Visualization Studio, NASA GSFC
As a result of this collection of diverse yet complementary scientific evidence, the world community began to limit the use of CFCs and ratified the Montreal Protocol in 1988, which imposed strict international limits on CFC use. In 1995, Molina, Rowland, and Crutzen shared the Nobel Prize in chemistry for their research that contributed to our understanding of ozone chemistry. The ozone story (further detailed in our Resources for this module; see The Ozone Depletion Phenomenon under Research) highlights an important point: Scientific research is multi-dimensional, non-linear, and often leads down unexpected pathways. James Lovelock had no intention of contributing to the ozone depletion story; his work was directed at quantifying atmospheric CFC levels. Although gaining an understanding of the ozone hole may appear as a linear progression of events when viewed in hindsight, this was not the case at the time. While each researcher or research team built on previous work, it is more accurate to portray the relationships between their studies as a web of networked events, not as a linear series. Lovelock's work led Molina and Rowland to their ozone depletion models, but Lovelock's work is also widely cited by researchers developing improved electron capture detectors. Molina and Rowland not only used Lovelock's work, but they drew on the research of Crutzen, Johnston, Clyne, Walker, and many others. Any single research advance was subsequently pursued in a number of different directions that complemented and reinforced one another – a common phenomenon in science. The entire ozone story required modeling, experiments, comparative research, and descriptive studies to develop a coherent theory about the role of ozone in the atmosphere, how we as humans are affecting it, and how we are also affected by it. Comprehension Checkpoint The ozone research story shows that, in practice, scientific research is Scientific research methods are part of the practice through which questions can be addressed scientifically. These methods all produce data that are subject to analysis and interpretation and lead to ideas in science such as hypotheses, theories, and laws. Scientific ideas are developed and disseminated through the literature, where individuals and groups may debate the interpretations and significance of the results. Eventually, as multiple lines of evidence add weight to an idea, it becomes an integral part of the body of knowledge that exists in science and feeds back into the research process. Figure 5 provides a graphical overview of the materials we have developed to explain the real practice of science, and the key elements are described below. Figure 5: A graphical overview of our modules that detail how science is practiced – multiple research methods are influenced by many factors, and the process has feedback loops leading to new ideas and research studies.(To download the diagram in PDF format click here.)
Despite the fact that different scientists use different methods, they can easily share results and communicate with one another because of the common language that has developed to present and interpret data and construct ideas. These shared characteristics allow studies as disparate as atmospheric chemistry, plant biology, and paleontology to be grouped together under the heading of "science." Although a practicing scientist in any one of those disciplines will require very specialized factual knowledge to conduct their research, the broad similarities in methodology allow that knowledge to be shared across many disciplines. SummaryScientists use multiple methods to investigate the natural world and these interconnect and overlap, often with unexpected results. This module gives an overview of scientific research methods, data processing, and the practice of science. It discusses myths that many people believe about the scientific method and provides an introduction to our Research Methods series. Key Concepts
Which method of observation involves the recording of people's behavior in their natural environments with little or no personal intervention?Naturalistic observation is different than structured observation because it involves looking at a subject's behavior as it occurs in a natural setting, with no attempts at intervention on the part of the researcher.
What is a systematic sample in cross cultural research?Systematic sampling is a sampling process that defines a process by which each sample is selected. If you put all of the population in a list, a systematic sampling would be to take every third item until you collect the desired sample size.
Is the method of observation that involves the recording of people's behavior in an environment created by the researcher?Naturalistic observation is an observational method that involves observing people's behavior in the environment in which it typically occurs. Thus naturalistic observation is a type of field research (as opposed to a type of laboratory research).
Which approach in cross cultural psychology argues that psychological phenomena are basically the same in all cultures?Psychologists supporting the absolutist approach argue that psychological phenomena are basically the same across cultures. However, the occurrences of certain processes and behaviors may vary from culture to culture.
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