What Is Experimental Psychology?

To reach an accurate and safe conclusion, researchers often use different scientific methods. This is the main area of ​​focus for experimental psychology. Experimental psychology explores basic concepts, such as memory and motivation, in areas such as child, social, and educational psychology.

Almost all experimental psychology work takes place in controlled settings, such as research laboratories.  Experimental psychologists manipulate research variables to discover relationships between cognition and behavior. 

While each branch of psychology strives to understand human thinking and behavior , experimental psychology focuses on conducting controlled experiments with designated variables, test subjects, and statistical results.

Origin of experimental psychology

For some it was Charles Darwin with  The Origin of Species  who started the field of experimental psychology. On the one hand, there is no doubt that Darwin’s revolutionary theory sparked interest in the relationship between biology and psychology. In the early 1900s, psychologists began using the natural sciences to analyze and explain the human mind.

However, this inaccurate understanding of the human mind as a machine was replaced by functionalist theories. For example, William James, the father of American psychology, was heavily influenced by evolutionary biology and promoted the idea that the mind is naturally adaptive, sensitive, and intelligent.

In the end, it was behaviorism and other branches of modern psychology that contributed to the formation of what we know today as experimental psychology.

What do experimental psychologists do?

Experimental psychologists want to study behaviors, as well as the different processes and functions that support these behaviors. The tests are performed on test subjects to understand and learn about different topics, including perception, memory, sensation, learning, motivation, and emotions.

To better understand the approach to experimental psychology, there are four fundamental principles that researchers generally agree on for psychological studies to be considered reliable. These principles are:

• Determinism : Experimental psychologists, like most scientists, accept the notion of determinism. This is the assumption that any state of an object or event is determined by previous states. In other words, behavioral or mental phenomena are typically expressed in terms of cause and effect. If a phenomenon is sufficiently general and widely confirmed, it can be called ‘law’. Psychological theories serve to organize and integrate laws.
• Empiricism : Knowledge is only derived mainly from experiences related to the senses. Therefore, only things that are observable can be studied. The notion of empiricism requires that hypotheses and theories be contrasted with observations of the natural world and not with a priori reasoning, intuition, or revelation.

• Parsimony : It is the search for simplicity. According to this principle, investigations must be carried out on the simplest of theories. If we are faced with two different and contrasting theories, the more parsimonious or basic theory is preferred.
• Probability : According to this principle, hypotheses and theories should be testable over time. If a theory cannot be proven in any conceivable way, then many scientists consider the theory to be nonsense. Probability implies ‘falsifiability’, which is the idea that some set of observations could prove the theory wrong.

To these principles can be added that of operational definition or operationism. The operational definition implies that a concept is defined in terms of concrete and observable procedures. Experimental psychologists attempt to define currently unobservable phenomena, such as mental events, by connecting them to observations by chains of reasoning.

Reliability and validity

Reliability measures the consistency, verifiability, or repeatability of a study. If the research can be repeated and still produces the same results (either in a different set of participants or over a different period of time), then it is considered reliable.

For its part, validity measures the relative precision or accuracy of the conclusions drawn from a study. It is the relative accuracy and correctness of psychological studies. To determine the validity of a measure quantitatively, it must be compared with a criterion.

Several types of validity have been distinguished. They are as follows:

• Internal validity:  in which the study provides strong evidence of causality between two factors. A study that has a high internal validity concludes that, in fact, it is the manipulation of the independent variable that is responsible for the changes in the dependent variable.
• External validity:  in which the study can be replicated in different populations and still produce the same results.
• Construct validity:  in which it is found that the independent and dependent variables are accurate representations of the abstract concepts that are being studied.
• Conceptual validity:  in which the hypothesis being tested supports the broader theory that is also being studied.

Final comments

Although experimental psychology is sometimes considered a branch of psychology, experimental methods are widely used in all areas of psychology.

For example, developmental psychologists use experimental methods to study how people grow during childhood and throughout life.

Social psychologists, for their part, use experimental techniques to study how people are influenced by groups. Meanwhile, health psychologists also use experimentation to better understand the factors that contribute to well-being and illness.