Psychological Research

How do we know what changes and stays the same (and when and why) in development? We rely on research that employs the scientific method, allowing us to have confidence in the findings. How data are collected and analyzed varies by the type of information sought. The design of the study will affect the data and the conclusions that can be drawn from them about actual age changes.

An essential part of learning any science is having a basic knowledge of the techniques used in gathering information. The hallmark of scientific investigation is following a set of procedures designed to keep questioning or skepticism alive while describing, explaining, or testing any phenomenon. Not long ago, a friend told me that he did not trust academicians or researchers because they often seem to change their stories. That, however, is precisely what science is all about; it involves continuously renewing our understanding of the subjects in question and an ongoing investigation of how and why events occur. Science is a vehicle for going on a never-ending journey. In the area of development, we have seen changes in recommendations for nutrition, explanations of psychological states as people age, and parenting advice. So think of learning about human development as a lifelong endeavor.

Personal Knowledge

How do we know what we know? Take a moment to identify two things that you know about adolescence. Now, how do you know? Chances are you know these things based on your own history (experiential reality), what others have told you, or cultural ideas (agreement reality) (Seccombe and Warner, 2004). There are several problems with drawing conclusions based on personal experiences. Read the following sentence aloud:

Paris in the
the spring

Are you sure that is what it said? Read it again.

If you read it differently the second time (adding the second “the”), you just experienced one of the problems with relying on personal inquiry; that is, the tendency to see what we believe. Our assumptions very often guide our perceptions; consequently, when we believe something, we tend to see it even if it is not there. Have you heard the saying, “seeing is believing”? The truth is, however, just the opposite: believing is seeing. This problem may just be a result of cognitive ‘blinders,’ or it may be part of a more conscious attempt to support our own views. Confirmation bias is the tendency to look for evidence that supports our own views, and in doing so, we often overlook contradictory evidence.

Philosopher Karl Popper suggested that the distinction between what is scientific and what is unscientific lies in the fact that science is falsifiable; scientific inquiry involves attempts to reject or refute a theory or set of assumptions (Thornton, 2005). A theory that cannot be falsified is not scientific. Much of what we do in personal inquiry involves drawing conclusions based on our personal experiences or validating our own experiences by discussing what we think is true with others who share the same views.

Science provides a more systematic approach to making comparisons and guarding against bias. One technique used to avoid sampling bias is to select participants for a study in a random way. This means using a technique to ensure that all members have an equal opportunity to be selected. Simple random sampling may involve using a set of random numbers as a guide in determining who is to be selected. For example, if we have a list of 400 people and wish to randomly select a smaller group or sample to be studied, we use a list of random numbers and select the case that corresponds with that number (Case 39, 3, 217, etc.). This is preferable to asking only those individuals with whom we are familiar to participate in a study; if we conveniently chose only people we know, we would know nothing about those who had no opportunity to be selected. There are many more elaborate techniques that can be used to obtain samples that accurately represent the composition of the population being studied. However, even though a randomly selected representative sample is preferable, it is not always used due to costs and other limitations. As a consumer of research, however, you should be aware of how the sample was obtained and consider this when interpreting the results. It is possible that the findings were limited to that sample or similar individuals and not generalizable to everyone else.