What is experimental psychology? |

Introduction

Wilhelm Wundt
founded the field of psychology, which he termed “experimental psychology,” on establishing his lab at the University of Leipzig in Germany in 1879. Wundt was the first to identify psychology as a separate science, on par with the natural sciences such as biology, physics, and chemistry. Wundt himself was trained as a physiologist and philosopher, and the methods he used in both of those disciplines combined to give structure to the new field. The role of experimental psychology at its founding was to answer philosophical questions using scientific methods. Wundt defined consciousness as the appropriate subject matter for experimentation and devised methods such as introspection (reporting on inner experiences by the subjective observer) to study the activity and structures of the mind (the basis for the school of thought later termed structuralism). Wundt was responsible for removing psychology from the metaphysical realm, providing conclusive evidence that the mind could be studied scientifically. This profoundly affected the development of psychology in the years following, establishing an emphasis on the importance of scientific research methods.

Over the first century of its existence and beyond, psychology came to be defined as the scientific study of consciousness, emotions, and behavior, and experimental psychology is no longer the only type. There now are many other subfields in psychology, such as clinical psychology, social psychology, and developmental psychology, but experimental methods still underlie most of them because that is how knowledge is accumulated in each area. Experimental psychology itself has expanded to include both basic and applied research.

Basic and Applied Research

Basic research, the kind that Wundt himself conducted, is undertaken for the purpose of advancing scientific knowledge, even if the knowledge gained is not directly relevant to improving the lives of individuals. This type of research is more likely to take place in laboratory settings, often on university campuses, using undergraduate students or specially bred lab animals as experimental subjects. These settings do not approximate the natural environment, permitting factors that could interfere with interpretation of the results to be controlled or eliminated, making conclusions more accurate. Examples of basic research include studying animal behavior, examining the perceptual abilities of humans, or determining the factors contributing to aggressive behavior.

Basic research was the only type of research conducted in experimental psychology until the first decade of the twentieth century, when applied psychology was introduced through the American school of thought termed Functionalism. It was at this time that psychologists began being interested not only in how the mind works but also in how the mind works to help individuals interact with their environment. Most of the newer research involved conducting research with humans in their natural environment. For example, school psychologists were trying to find effective tests so that students could be taught at the appropriate levels (the first intelligence tests) and to identify how behavioral problems in the school or home could be controlled. Researchers also were trying to determine the factors that would increase efficiency and satisfaction in the workplace. In addition to these scenarios, researchers now attempt to solve such problems as finding effective ways to teach children with developmental disabilities, identifying new therapy techniques for those with psychological disorders, and developing strategies to increase healthy behaviors such as exercise and decrease unhealthy behaviors such as drug abuse. Applied research results tend to be more generalizable to others, but the relative lack of control sometimes limits the conclusions that can be drawn based on the results, so caution must be taken when recommending procedures from experiments.

The Scientific Method

The methods used for conducting either basic or applied research in experimental psychology are essentially the same as for conducting research in any other science. The first step in the process is identifying a research problem, a question that can be answered by appealing to evidence. Next will be a search for a theory, a general statement that integrates many observations from various research studies and is testable. From the theory is formed a hypothesis, a more precise version of the theory that is a specific prediction about the relationship between the variables in the research being conducted. At this point, the research is designed, which involves decisions about how many and what type of participants will be used, where the research will be conducted, the measurement procedures to be developed, and so on. After the relevant data are collected, they must be analyzed visually or statistically. This allows the drawing of conclusions about the findings, which are communicated to others in the form of presentation or publication. The research process is circular, in that the more questions that are answered the more new questions arise, and that is how science advances.

There are key characteristics that must be present for good scientific research. Objectivity means that research must be free from bias. Data are to be collected, analyzed, interpreted, and reported objectively so that others are free to draw their own conclusions, even if they are different from those of the researchers. Control of factors that may affect the results of the research is necessary if those factors are not the specific ones being studied. For example, control for the effects of gender can be accomplished by ensuring that research samples include approximately the same number of males and females, unless the researcher is interested in looking for potential gender differences in behavior. In that case, the researcher would still want to control for factors such as age, education, or other characteristics that might be relevant. Control allows researchers to be more confident about the accuracy of their conclusions.

Operationism involves defining the variables to be studied in terms of the way they are measured. Many different operational definitions are possible for a particular concept such as aggression or love, and the results of research studies that use different operational definitions when combined provide more complete knowledge than if only one operational definition were used. Finally, replication is a key part of the research process because the aim of science is to accept only knowledge that has been verified by others. This requirement that results be replicable helps prevent bias and furthers objectivity.

Descriptive Versus Experimental Research

Descriptive research is conducted to describe and predict behavior. Often these results are useful on their own, or such studies provide information to be used in future, more controlled, experiments. It can include archival research, an analysis of existing records of behavior, case studies, in-depth analysis of one or a few individuals, naturalistic observation, monitoring the behavior of subjects in their natural environment, or survey research in which individuals report on their own behavior. Descriptive research also includes correlational research, which examines relationships between variables that cannot be manipulated (such as gender, family background, or other personal characteristics that are not changeable). Correlational studies make it possible to predict changes in one variable based on observing changes in another, but as in all descriptive research, it is impossible to know whether or not changes in one variable caused the observed changes in another, so the conclusions to be drawn are limited.

The only type of research that can explain the causes of behavior is true experimental research, because that is the only type of research in which variables can be manipulated to see the observed effects on behavior. The variable that is manipulated is called the independent variable, and the variable that is measured to see the effects of the manipulation is called the dependent variable. Independent variables can be manipulated by measuring the effects of their presence versus absence (for instance, how reaction times differ when alcohol is consumed), their degree (how reaction times change as more alcohol is consumed), or their type (reaction times when alcohol is consumed as compared to when caffeine is consumed). Dependent variables are measured in terms of their latency (how long it takes for a response to occur) or duration (how long a response lasts), force (how strong the response is), rate or frequency (how often a response occurs within a period of time), or accuracy (the correctness of the response). There can be one or more each of the independent and dependent variables in any experiment, although having more variables increases the complexity of the analysis of the results. Every other variable that is present that could have an effect on the dependent variable in addition to the independent variable is considered an extraneous variable. These must be controlled (kept constant) or eliminated so that the researcher can be sure that changes in the dependent variable are due only to changes in the independent variable.

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