Working memory span forms an important cornerstone of current accounts of cognition, and cognitive development. We describe data that challenge the conventional interpretation of span as a measure of working memory capacity. We argue that the implications of these data undermine the analysis provided by Caplan & Waters concerning the role of working memory in sentence comprehension.

Cowan has written a meticulous and thought-provoking review of the literature on short-term memory. However, reflections on one area of evidence, that of working memory span, shows the extent to which the research debate can be circumscribed by choice of experimental paradigms.