Introduction

Despite the differences in their interests, areas of study, and approaches, all scientists have one thing in common: they rely on scientific methods. Researchers use scientific methods to create new knowledge about the causes of behaviour, whereas practitioners, such as clinical-, counselling-, industrial/organizational-, and school-psychologists or field biologists and engineers use existing research to enhance the everyday life of others. Scientific research is important for both researchers and practitioners.

Of all of the sciences, psychology is probably the one that most non-scientists feel they know the most about. Because psychology is concerned with people and why they do what they do, we are all “intuitive’ or “naive” psychologists. We rely on common sense, experience, and intuition in understanding why people do what they do. We all have an interest in asking and answering questions about our world, and in making sense of ourselves and other people. We want to know why things happen, when and if they are likely to happen again, and how to reproduce or change them. Such knowledge enables us to predict our own behaviour and that of others. We may even collect data (i.e., any information collected through formal observation or measurement) to aid us in this undertaking.

It has been argued that people are “everyday scientists” who conduct research projects to answer questions about behaviour (Nisbett & Ross, 1980). When we perform poorly on an important test, we try to understand what caused our failure to remember or understand the material and what might help us do better the next time. When our good friends Monisha and Charlie break up, despite the fact that they appeared to have a relationship made in heaven, we try to determine what happened. When we contemplate the rise of terrorist acts around the world, we try to investigate the causes of this problem by looking at the terrorists themselves, the situation around them, and others’ responses to them.

The problem of intuition

The results of these “everyday” research projects teaches us about human behaviour. We learn through experience what happens when we give someone bad news, that some people develop depression, and that aggressive behaviour occurs frequently in our society. We develop theories to explain all of these occurrences; however, it is important to remember that everyone’s experiences are somewhat unique. My theory about why people suffer from depression may be completely different to yours, yet we both feel as though we are “right.” The obvious problem here is that we cannot generalize from one person’s experiences to people in general. We might both be wrong!

The problem with the way people collect and interpret data in their everyday lives is that they are not always particularly thorough or accurate. Often, when one explanation for an event seems right, we adopt that explanation as the truth even when other explanations are possible and potentially more accurate. Furthermore, we fall victim to confirmation bias; that is, we tend to seek information that confirms our beliefs regardless of the accuracy of those beliefs and discount any evidence to the contrary. Psychologists have found a variety of cognitive and motivational biases that frequently influence our perceptions and lead us to draw erroneous conclusions (Fiske & Taylor, 2007; Hsee & Hastie, 2006; Kahneman, 2011). Even feeling confident about our beliefs is not an indicator of their accuracy. For example, eyewitnesses to violent crimes are often extremely confident in their identifications of the perpetrators of these crimes, but research finds that eyewitnesses are no less confident in their identifications when they are incorrect than when they are correct (Cutler & Wells, 2009; Wells & Hasel, 2008). In summary, accepting explanations without empirical evidence may lead us to faulty thinking and erroneous conclusions. Our faulty thinking is not limited to the present; it also occurs when we try to make sense of the past. We have a tendency to tell ourselves “I knew it all along” when making sense of past events; this is known as hindsight bias (Kahneman, 2011). Thus, one of the goals of psychology education is to make people become better thinkers, better consumers of ideas, and better at understanding how our own biases get in the way of true knowledge.

Why scientists rely on empirical methods

All scientists, whether they are physicists, chemists, biologists, sociologists, or psychologists, use empirical methods to study the topics that interest them. Empirical methods include the processes of collecting and organizing data and drawing conclusions about those data. The empirical methods used by scientists have developed over many years and provide a basis for collecting, analyzing, and interpreting data within a common framework in which information can be shared. We can label the scientific method as the set of assumptions, rules, and procedures that scientists use to conduct empirical research.

Although scientific research is an important method of studying human behaviour, not all questions can be answered using scientific approaches. Statements that cannot be objectively measured or objectively determined to be true or false are not within the domain of scientific inquiry. Scientists therefore draw a distinction between values and facts. Values are personal statements such as “Abortion should not be permitted in this country,” “I will go to heaven when I die,” or “It is important to study biology.” Facts are objective statements determined to be accurate through empirical study. Examples are “The homicide rate in Canada has been generally declining over the past 45 years” or “Research demonstrates that individuals who are exposed to highly stressful situations over long periods of time develop more health problems than those who are not.”

When we try to find new facts, we express our prediction about what we believe to be true in a hypothesis. An example of a hypothesis would be “People who eat fruits and vegetables daily have better health than people who never eat fruits and vegetables.” For this to become fact, we must test this hypothesis in research and show the evidence that supports it. This is a testable hypothesis, because it would be possible to do the research. It is also falsifiable, meaning that if our prediction is wrong, and eating fruits and vegetables daily does not lead to better health, we will have the data to show us that we are wrong.

Ideas or values are not always testable or falsifiable: science can neither prove nor disprove them. For example, the famous Viennese neurologist Sigmund Freud, father of psychoanalysis, believed that the unconscious part of our mind is ultimately responsible when we experience anxiety, depression, and other negative emotions. He thought that emotional conflicts and adverse childhood experiences became lodged in the unconscious because consciously acknowledging them was threatening to our sense of wellbeing. This theory is built on a largely untestable idea: the existence of an unconscious. Given that by definition we cannot describe it, it is difficult to see how we could prove its existence or its role in our lives. That does not mean that the unconscious does not exist, but as we’ll see, we need to find a way to look for its existence using testable and falsifiable hypotheses.

Although scientists use research to help establish facts, the distinction between values or opinions and facts is not always clear-cut. Sometimes statements that scientists consider to be factual turn out later, on the basis of further research, to be partially or even entirely incorrect. Although scientific procedures do not necessarily guarantee that the answers to questions will be objective and unbiased, science is still the best method for drawing objective conclusions about the world around us. When old facts are discarded, they are replaced with new facts based on new and correct data. Although science is not perfect, the requirements of empiricism and objectivity result in a much greater chance of producing an accurate understanding of the world than is available through other approaches.