Scientific Reasoning in Psychology

  • by Dr. Janet Waters  (2000/revised 2017)

    Empiricism in the Social Sciences

    The Social Sciences include the disciplines of Psychology, Sociology, Anthropology, Archaeology, Geography, Economics, and Political Studies. All these disciplines use empirical methods to study humans: as individuals and in groups (psychology and sociology); across cultures (anthropology) and geographies; and in their political and economic structures.

    If your impressions about psychology and the other social sciences have come from media depictions, you might get the impression that our theories and hypotheses are based on unfounded, sometimes bizarre, intuitions and speculations. In fact, our theories, hypotheses and speculations are evidence-based, tested by sound scientific reasoning and methodology and empirical evidence.

    Empiricism is the "philosophical tenet that knowledge comes through experience... Knowledge about the world is based on careful observation, not on common sense or speculation" (Krause, Corts, Smith & Dolderman, 2018, p. 12). It is not that non-empirical methods are always wrong; they may often lead us to correct answers, and creative insight and intuition is valuable in scientific breakthroughs. But science has added an essential empirical element to our age-old human search for the truth. With science, we can verify our intuitions, beliefs, and logical deductions with objective and accurate scientific evidence using the methods of systematic observation and experimentation.

    Psychology was considered to be a part of philosophy until 1875, when the first psychologists began to apply the empirical methods of scientific reasoning and methodology to answer questions about human behaviour that had long been asked by philosophy. As an example, for millennia, philosophers and poets speculated about the nature of dreams, whether everybody dreamed or only a special few, whether dreams were valuable or nonsensical. This question could not be answered by personal experience or logic, since individuals' experiences with dreams vary greatly. In fact, many people claimed they never dreamed. Some people believed that dreams were rare, or a sign of madness; others thought they were a divine gift. Some popular beliefs about dreams even today include the belief that dreams last only for a few minutes; that a sleepwalker should never be woken up; and that if a dreamer dies in a dream, they will actually die.

    However, using systematic observation, psychologists were able to discover that, in fact, everyone dreams several times every night, dreams can last as long as an hour, and that none of the other beliefs noted above are true.

    The Scientific Attitude

    So science acquires knowledge through systematic observations and experimentation. This objective research then leads to further theoretical hypotheses, which then lead to further observations and experimentation. In making our observations, it is important that we control for all other factors that may influence our research and mislead us in drawing our conclusions. Therefore science depends on an attitude of "open-minded skepticism" and critical thinking. All theories must be empirically tested, and the scientific evidence that results must be evaluated by objective and knowledgeable peer researchers, before being accepted as valid.

    Scientific Methods

    Scientific methods of systematic observation and experimentation have many different forms when studying human behaviour and cognition, as observing behaviour can't reveal what the person was thinking or experiencing, and thoughts and experiences can't be directly observed and verified. A person's self-report of their experience or thinking may not be accurate. Do you remember your 9th birthday? You are likely to forget something that happened so long ago. Even if you think you remember it, you may be mistaken, or confusing one birthday with another one, or remembering the photos of your birthday, not the event itself. To help control for problems of self-report, there are different scientific methodologies in psychology to study different kinds of content. 

    Since the social sciences are studying human beings, not rocks or plants, we have to take into account different ethical and pragmatic concerns than those of the natural sciences. An observation can be much altered if the person knows they are being observed, or knows they are a participant in an experiment. People behave differently when they know a researcher is observing them.  Even the researchers' own knowledge about their research aims can affect the results, so researchers often control even that variable, using what is called a "double-blind study". So researchers have often hidden or even deceived subjects about the topic of the study (until the research was over) to avoid influencing their behaviour - which leads to questions about research ethics.  

    Although all the social sciences are studying humans, there are differences across the social science disciplines in scientific methodology as well, because of differences in the topics, goals and difficulties of the discipline. Archaeologists, for example, may have only physical evidence and artifacts to use as their data in studying a site from thousands of years ago. A historian would need to use documents from the era they are studying, and try to validate the accuracy of that evidence when possible. Anthropologists must try to objectively observe, study, and understand cultures that may be very different from their own. In psychology, research methods vary according to the topic of study, and range from controlled laboratory experiments, to systematic observation, to cognitive testing, surveys and case studies. Each method has its advantages and disadvantages, which researchers and students must be aware of to evaluate the accuracy of the research findings.

    Scientific Objectivity

    In all the social sciences, researchers must be very careful not to allow their cultural and theoretical biases to shape their observations and affect their findings. Researchers, like the rest of us, are raised in the particular perspectives of their culture, class and gender, and profoundly shaped by their culture's socio-cultural, historical, philosophical, religious, gender and class experiences and beliefs. This can limit researchers', and students', awareness of other perspectives and beliefs, and bias their research methods and results. Also, researchers are trained within a certain set of theoretical perspectives (e.g. the Cognitive perspective in psychology). Since the research is conducted to test a particular hypothesis or theory, the researchers' theoretical perspective can also strongly bias their methods and findings.

    Therefore keeping an attitude of scientific objectivity and skepticism is essential. In part, this is why a theory would never be accepted on the basis of one research study. We eventually build a solid foundation of many research studies on a topic, each of which is published only if it passes the critical eye of other knowledgeable researchers. From this foundation of research data, theories are then further refined or new theories proposed.

    So as well as being skeptical of common sense and personal experience, a researcher must also be open-minded. Researchers must try hard to set aside their personal beliefs and attitudes, and the limitations of their culture and gender, as well as their theoretical perspective, to carry out objective, unbiased research.

    Like researchers, students in the social sciences must also have an attitude of open-minded skepticism and critical thinking, and be able to objectively consider ideas and research findings that will challenge their personal beliefs and preconceptions. This can be difficult for thinkers who are looking for clear, simple, factual answers to memorize for the exam! Understanding any topic or question in Psychology (such as: "What causes violence in our schools?") will mean understanding: a) the main issues in the topic; b) the different theories or perspectives on this question; c) the dozens of factors that empirical research has found to be involved; and d) being able to evaluate this research for validity. To do this, you will have to set aside your biases and preconceptions, avoid the temptation of superficial answers, and consider what the theories and research says. And that can be particularly difficult to do, if the research conflicts with your beliefs.