And what he wanted to do was to provide a practical demonstration of why it occurs. This phenomenon of normal distribution fascinated Galton. And so this bell curve characterises the frequency of occurrence of this particular trait in the population.” But there will be some people who are way out in the tails of this distribution, but not very many of them. “Typically, a large number of people will be clustered around the mean behaviour - the average behaviour - for a particular trait, be that the average height or average IQ. It’s this curve which has a shape like a bell, so it’s very high in the middle and low towards the edges, and it can be used to describe a wide range of naturally occurring phenomena from height, for example, through to IQ scores. He was particularly curious about why certain human characteristics such as height rather than randomly varying within a population, appeared to vary in a very orderly, recognisable way.Īnd specifically according to something called a normal distribution.ĭr Kit Yates, senior lecturer in mathematics at Bath University, says: “The normal distribution is often known as the bell curve. That interest, in passing on genes as it were, was actually how he came to be interested in statistics.” He was particularly interested in how certain characteristics are inherited.

Invented by Galton in 1876, he used the board to develop some of the most powerful concepts in yet another field he worked in: statistical mathematics.ĭr Snezana Lawrence, a mathematical historian at Anglia Ruskin University says: “He was very interested in biology and medicine and the application of mathematics to it. He’s even credited with inventing the questionnaire!īut despite such accomplishments, perhaps Galton’s most important and influential legacy is unknown to most people, hidden inside an obscure contraption named after him: the Galton Board. The renowned polymath was born here in Birmingham, England, in 1822, and was responsible for many notable and varied scientific advancements in the 19th century, including the development of fingerprint classification, psychometric testing and the first weather map. You may not have heard of him, but Sir Francis Galton was a Victorian genius.

Galton board video