Essay Experimental Design

A fundamental characteristic of experimental approaches in relation to psychological studies is that researchers can observe and analyse certain behaviours in an environment of that they can control. By exposing participants to certain treatments or conditions, researchers are able to attain identification of causality. There are two primary designs in which experimenters can construct said treatments or conditions. In a “within-subjects” design experiment, all participants are exposed to every level of the independent variable being tested. In a “between-subjects” design, participants are randomly assigned to only one level of the independent variable being tested. Both designs have their merits, and the choice of designs should be carefully considered in the context of the question being studied and in the execution of the research study (Charness, Gneezy, Kuhn, 2011). A third factor to also consider is the nature of the research design, choosing the one which provides the sensitive and unconfounded test of the independent variable (Schweepers, 2009) In this essay I will discuss, using experiments from published sources, the advantages and disadvantages of between-subjects designs. What motivates the use of this type of design and how potential problems associated with this type of design are usually tackled.

Between-subjects designs are one of the most common experimental designs in many scientific disciplines, especially within the world of Psychology. In the case of a tradtional experiment, one group will be exposed to some kind of experimental condition (treatment), while the second group is not, so as to serve as a comparison to the group exposed to the condition. This comparison group is termed as the control group,and the group exposed to the treatment is termed as the experimental group. Participants cannot be part of both groups, if more than one condition is tested, then a completely new group is required in order to perform the experiment