Variability at Group Level vs. Variability in Individuals

Abstract

Different authorities have taken different perspectives with regard to the issue of variability, its existence and form. Some have claimed that variability exists in individuals and is either systematic or non-systematic. Others propose that variability as an individual phenomenon occurs only in its systematic form. Yet, a third position claims that variability in individuals does not exist, rather it occurs only at a group level. In this paper I discuss the latter two positions. First, I discuss the position that variability exists only as a group phenomenon. Then, I present a counter-argument for systematic variability in individuals. The argumentation is based on empirical findings.