In his open laboratory, people could have the acuity of their vision and hearing measured, as well as their reaction times to different stimuli. Sir Francis Galton was the first scientist who attempted to devise a modern test of intelligence in 1884.
Measuring Intelligence - Noteworthy Contributors Sir Francis Galton In practice, qualifying for Mensa in the top 2% means scoring 132 or more in the Stanford-Binet test, or 148 or more in the Cattell equivalent. Mensa admits individuals who score in the top 2% of the population, and they accept many different tests, as long as they have been standardised and normed, and approved by professional psychologists’ associations. Two of the most well-known IQ tests are 'Stanford-Binet' and 'Cattell' (explained in more detail below). When current IQ tests were developed, the average score of the norming sample was defined as IQ 100 and standard deviation (a statistical concept that describes average dispersion) up or down was defined as, for example, 16 or 24 IQ points greater or less than 100.
