Just like research in physics or chemistry, research in psychology is guided by the principles of the scientific method. An observation is made about a behavior of interest. A hypothetical explanation is proposed. Then an experiment is conducted to determine whether the hypothetical explanation is valid or not. For example, a psychologist might notice that adolescents who engage in violent behavior often report that they play violent video games. This might lead to the following hypothesis: violent video games cause violent behavior. An experiment could be conducted in which one group of subjects (the experimental group) plays violent video games, while another group (the control group) plays nonviolent games. The subjects could then complete a questionnaire probing for violent versus nonviolent solutions to hypothetical conflicts. In this example, the kind of video game would be the independent variable, and the responses on the questionnaire would be the dependent variable. If the experimental group tended to show more violent responses on a subsequent questionnaire, we would conclude that the hypothesis was valid: violent video games do promote violent behavior. Otherwise we might conclude that the hypothesis was invalid: violent video games do not promote violent behavior.

In this activity, you will have the opportunity to complete three stages of the scientific method.

Observation: you will watch a group of circles moving against a colored background.

Hypothesis: you will generate hypotheses regarding the movement of the balls; for example, when two orange balls collide, they fuse into one ball.

Experiment: you will create a control group and an experimental group to test your hypothesis.