IQ (Intelligence quotient)

The IQ (Intelligence Quotient) is the most highly used tool in psychometry, a branch of diffential psychology. It-facilitates the simple quantification of a good many of-a subject's cognitive capacities, in other words their different intelligences (in the usual sense of the term) and their general Intelligence (G factor) which corresponds to a biological characteristic not Yet fully understood. Based on more than 130 years of study into psychometry, the IQ is the both the weakest and most tested tool in psychology. From approximately 7 years on, its results are constant throughout life (after application of an age coefficient) and they are correlated to numerous biological and social criteria. Not all of its aspects have been discovered however and it is important to remind oneself that it represents an indirect, imperfect measure of intelligence. This article gives a back history of research on intelligence, compares the two main approaches (manifestations or causes of intelligence),describes the most used test in France (Wechsler) and present the major discoveries. Such a broad overview of the evolution of research helps us realise that the IQ in no way corresponds to what is generally written on the subject and that there are more complementarities between the different theories (Single Intelligence or Multiples Intelligences for example) than there are oppositions.