We didn’t see these effects for infants in the comparison group or for infants who received books with generic labels.

Ten years later, the comparison group had gained an average of 1.6 per cent.

The winners of the award were far more altruistic than the comparison group.

Sixty per cent of those receiving the largest amount had an excellent recovery after three months, compared with 22 per cent in the untreated comparison group.

This control group serves as an untreated comparison group during the study, but eventually goes on to receive treatment at a later date.