In "A Short History of Nearly Everything," Bill Bryson discusses an intriguing comparison between the brain capacities of Neandertals and modern humans. He notes that Neandertals had a larger cranial capacity, approximately measured in litres, while modern Homo sapiens averaged around 1.4 litres. This significant disparity raises questions about the cognitive capabilities associated with brain size and efficiency, particularly when contrasted with late Homo erectus, a species often regarded as only marginally human.

The argument suggests that Neandertals, despite their larger brains, did not necessarily possess superior intelligence or functionality. Bryson argues that there is a distinct lack of evidence in evolutionary history to support the assertion that smaller brains can outperform larger ones in terms of efficiency. This perspective highlights a unique aspect of human evolution, questioning the simplified assumption that brain size directly correlates with intelligence.