The arrival of the Duke and Duchess of Cambridge's third child is delightful news - and three children means a much richer and more complex set of interactions in a family.

Many factors work to create a unique individual, but birth order is still one of the most powerful factors that shapes character - and could be the most powerful influence of all in determining social behaviour throughout a lifetime.

In 2013, Daniel Eckstein and his colleagues at Sam Houston State University looked at more than 200 studies into birth order characteristics and created a list of the most frequently cited qualities for each birth order position.

The eldest is the only child in a family who starts life enjoying the exclusive attention of their parents. As a result, they often develop good linguistic and social skills and we see these in Prince George already.

The downside is that firstborns can pick up on any anxiety new parents may feel and, when the next sibling comes along, they feel the loss more keenly. This leaves them with a strong thirst for approval from authority, and with that comes a powerful drive to succeed.