The Difficulty Psychologists Had in Defining the Concept of Intelligence

The difficulty psychologists had in defining the concept of intelligence year after year resulted in:

A) the concept remaining undefined despite the fact that the concept continued to be empirically investigated
B) intelligence no longer being investigated until psychologists finally agreed on a definition
C) one psychologist defining intelligence as ìwhat intelligence tests measureî
D) a tremendous and varied number of ìscientificî definitions of ìintelligenceî