A four-year-old's people-drawing ability provides an indicator of his or her intelligence at age 14, scientists have found.
Parents might laugh at their child's quaint crayon scribbles, but the balloon heads and stick-like limbs have a serious hidden meaning, research shows.
They reveal a connection with gene-driven intelligence that has a measurable effect 10 years later.
With the help of parents, psychologists got 15,504 children aged four to take part in a "draw-a-child" test, rating each picture with a score of zero to 12.
A "moderate" association was seen between higher scores and intelligence test results both at the age of four and 14.
Lead scientist Dr Rosalind Arden, from the Medical Research Council Social, Genetic and Developmental Psychiatry Centre at the Institute of Psychiatry, King's College London, said:
Drawings were judged on the presence and correct quantity of features such as the head, eyes, nose, mouth, ears, hair, body and arms.
A point was awarded for each correctly presented feature. For example, a drawing of a figure with two legs rather than four or none would receive one point for legs. Any clothing indicated also scored a point.