Recall, similarity judgment, and identification of trees: A comparison of experts and novices

We compare experts and novices in their recall, similarity judgment, and identification of trees. These tasks assess different aspects of informants' knowledge of trees. Experts agree substantially on all three tasks. However, they judge similarity of pictures of trees relying more on morphological and taxonomic features while judging similarity of names of trees relying more on utilitarian features. Novices recall few trees and accurately identify almost none of them, but substantially agree with each other in their similarity judgments of trees. Thus, we find that the natural world can be understood by experts and novices alike, but that training sharpens observations and informs about properties of species not obvious by direct observation. Moreover, the kinds of features used by experts in similarity judgments are influenced by how species are represented. These results confirm and extend findings in prior research of James S. Boster and Jeffrey C. Johnson and Douglas L. Medin and colleagues. They also demonstrate how the domain knowledge of experts arises out of the many different ways in which they engage the trees and out of the diversity of activities and purposes in their community of practice.