Can Children Read Evolutionary Trees?

Representations of the “tree of life” such as cladograms show the history of lineages and their relationships. They are increasingly found in formal and informal learning settings. Unfortunately, there is evidence that these representations can be challenging to interpret correctly. This study explored the question of whether children aged 7–11 can read these trees and, if so, what factors influence their understanding. A total of 28 children were shown cladograms with both different content (species and features shown) and form (how branches rotated). Questions required these children to reason about different aspects of cladogram interpretation and to search varying depths of the tree. Overall, children did remarkably well: 56% of their answers were completely correct after only 15 minutes of instruction. The youngest quartile of children performed worse than other ages, but there were no further age differences. Children's performance was influenced by the content and the depth of tree searched but not by the rotation of the branches. Like adults, they found reasoning about the relatedness of species particularly difficult. Children's explanations revealed varied insights: from correct semantic interpretation to syntactic interpretation to a variety of misunderstandings. Demonstration of this basic competency provides a foundation from which to design a more extended curriculum for children that uses cladograms to support evolutionary understanding.