Introduction

Knowing the intelligence of people can be very useful. For example, it helps to determine when a child might need special attention in school,  or if an extra stimulus might be desired to help develop intellectual abilities. Human intelligence is such an important factor in cognitive psychology that scientists have started to define and measure intelligence. The challenge is to accurately measure intelligence. Psychologists began by observing the extent to which a subject could perform (what they considered) intelligent thinking and behavior.

Psychologists have decided that intelligence is the ability to understand the world, think in a rational way, and use resources effectively when faced with a challenge (Wechsler, 1975; in Feldman, 1997, p.268). However, this definition is not enough to avhieve the more challenging task of measuring intelligence. To achieve this task, psychologists started developing intelligence tests, and batteries of measurements to determine someone's intelligence (Feldman, 1997, p.268).