Over the past half-century, insights from research have repeatedly rekindled our curiosity about how the structure of the brain relates to the process of thinking. For example, we now appreciate the importance of the synaptic connections that fill the pink stuff we used to call “neuropil” on brain histologic sections1 and the role of selective neuronal death (pruning) in early cortical maturation.2 We also understand at the molecular level the chemical events involved in the laying down of memories and acquisition of knowledge.3 We know that having a large brain does not necessarily make you smart, but is there a crucial structural measure that predicts cognitive function? Comparative observations across species have fueled a long-standing speculation that it is the convolutional complexity of the cortical ribbon rather than brain volume. The study of Rathbone et al. …