A pupillometric study of developmental and individual differences in cognitive effort in visual word recognition

Throughout the history of modern psychology, the neural basis of cognitive performance, and particularly its efficiency, has been assumed to be an essential determinant of developmental and individual differences in a wide range of human behaviors. Here, we examine one aspect of cognitive efficiency—cognitive effort, using pupillometry to examine differences in word reading among adults (N = 34) and children (N = 34). The developmental analyses confirmed that children invested more effort in reading than adults, as indicated by larger and sustained pupillary responses. The within-age (individual difference) analyses comparing faster (N = 10) and slower (N = 10) performers revealed that in both age groups, the faster readers demonstrated accelerated pupillary responses compared to slower readers, although both groups invested a similar overall degree of cognitive effort. These findings have the potential to open up new avenues of research in the study of skill growth in word recognition and many other domains of skill learning.