In a Study with a Group of Individuals Being Tested

Multiple Choice

In a study with a group of individuals being tested in a series of treatment conditions that extends over a relatively long time,it is possible that there will be systematic changes in the participants' physiology or psychology that occur during the time of the study.If these changes influence the participants' scores,causing scores at the end of the study to be different from scores at the beginning,the effect is called

A) history.
B) maturation.
C) instrumentation.
D) regression toward the mean.