Children spontaneously discover efficient solutions to a difficult sorting task.

Efficient algorithms can enhance problem-solving in many cognitive domains but can be difficult to discover and use. For example, classical studies of seriation suggest that children struggle to apply algorithmic strategies in a simple sorting problem. We investigated the spontaneous discovery of algorithmic solutions across development. We gave children a variant of the sorting problem with hidden object ranks: children sort animated bunnies into the right order, from the shortest to the tallest, when the bunnies are standing behind a wall so their heights are not visible. Children performed far above chance on this difficult sorting task, potentially because higher demands in memory and reasoning incentivized strategic behaviours. Children also independently discovered at least two efficient algorithmic solutions to the sorting problem: selection sort and shaker sort. Additionally, our developmental results show that older children were more effective sorters than younger children and used efficient sorting algorithms more frequently. These results indicate that children are far more competent at applying algorithmic solutions to sorting tasks than previous research would suggest, and performance on sorting tasks improves throughout development. Our work demonstrates that children have the ability to spontaneously organize their behaviours and find effective solutions to challenges in the world.