Introduction: what is intelligence?

Intelligence is arguably the most important construct in personnel selection, but what is its precise meaning, and that of IQ, g, general intelligence and cognitive abilities? The following conceptual differences should be noted:

Unfortunately, the above terms are often used interchangeably, producing frequent misunderstandings and unnecessary discussions (that is, discussions based on semantic confusion rather than valid theoretical assertions or empirical evidence). In order to avoid falling into this category we will use each of these terms in the context of Gottfredson's (2007, p. 219) conceptual distinctions. Thus, we will define IQ as intellectual quotient, or the score on a comprehensive battery of tests or global intellectual ability scale (omnibus test) that has a standardised scale with a mean score of 100 and a standard deviation of 15 points (see Section 6.3). On the other hand, the terms ‘g’, ‘general intelligence’ and ‘general mental ability’ (GMA) will be defined simply in terms of ‘the ability to learn’ or ‘general learning ability’ (Hunter, 1986) and used more or less interchangeably.