What is the phenomenon called where extreme scores tend to move closer to the average over time?

The phenomenon where extreme scores tend to move closer to the average over time is known as regression toward the mean. This concept is crucial in statistics and psychology because it highlights how extreme values, whether very high or very low, are likely to be followed by scores that are closer to the average in subsequent measurements.

This process occurs because extreme scores are often influenced by a variety of factors, some of which may be temporary or situational. As these factors change or stabilize, the overall performance or measurement is likely to reflect more typical or average conditions.

Understanding regression toward the mean is important in interpreting data effectively, especially in psychological research, where initial extreme performance may not represent a person's usual capabilities or traits. It emphasizes the need for caution in making long-term predictions based on initial extreme observations without considering this statistical tendency.

Other options like standard deviation and variance reduction relate to measures of data dispersion and variability, while mean reversion is a term that is often used in finance and can mean something different. Thus, regression toward the mean most accurately captures the phenomenon described in the context of scores becoming more average over time.