Suppose an experimental group is being taught letters of the alphabet as a treatment. At about the same time, the students are watching an educational program on television, from which they learn the names of the letters. What is the name of the threat that this problem illustrates?

History

Explanation: The history effect is an experimental research problem,which stems from the likelihood that an observed effect or result in our experiments is as a result of an extraneous affect or factor rather than the applied treatment used in the experiment.

In the scenario above, the group were being taught alphabet as treatment at about the same time when alphabet was being taught on television. Therefore, the result of the experiment may be influenced by the Television program rather than the applied treatment.