Reactivity is the predisposition to react physiologically to stress; believed to be genetically based in part; high reactivity is believed to be a risk factor for a range of stress-related diseases. The problem that the subjects of social research may react to the fact of being studied, thus altering their behavior from what it would have been normally.
It occurs when clients change their behaviors because they know that they are being observed. In the context of observation, the phenomenon in which individuals respond to the fact that they are being observed by changing their behavior. a participant's unplanned reaction to the researcher or research setting that may confound the results of the research A child's threshold for arousal, which indicates the likelihood of becoming distressed. The phenomenon that causes the reliability of a scale in behavior studies to be higher when an observer knows that his or her work is being monitored. Participants'' modification of their natural behavior in response to the fact that they are participating in a research study or the knowledge that they are being measured.