In his insightful exploration of the history of the emergence and establishment of the conceptual apparatus of psychology, Danziger (1997) stated a number of dimensions on which the concept of intelligence differs from the concepts of intellect and reason. First, although synonymous (The American Heritage Dictionary of the English Language, 1992), intellect and intelligence have different time trajectories: The concept of intelligence emerged much later, only at the end of the nineteenth century, while the concept of intellect was introduced at least as long ago as the appearance of Aristotelian writings. Second, the very surfacing of the concept of intelligence in psychological literature was deeply rooted in the discourse of the biological foundation of the human mind and its evolutionary development. The introduction of this concept led to the idea that stages of evolution somehow coincide with the amount of intelligence – the lower the evolutionary position, the less intelligence; the higher the position, the more intelligence. Third, the concept of intelligence has an embedded connotation of a quantitative distribution (one can have more or less intelligence compared to the other), whereas the concepts of intellect and reason appear to be dichotomous (one either has it or does not). Fourth, the concept of intelligence emerged in a time when school as a societal institution had started to become much more accessible to large masses of people; if previously the lack of education was primarily explained by one's social class, in the late nineteenth to the early twentieth century, the variation in educational achievement within social background groups was much larger than across social background groups, calling for a new (compared with social background) explanatory variable for educational failure.