Though it was based on very little evidence, many scientists thought that all mammalian brains, including the human brain, were made in the same way, with a number of neurons that was always proportional to the size of the brain.
Mesmo com base em pouca evidência, pensavam que o cérebro dos mamíferos, incluindo o humano, fosse feito do mesmo modo, com número de neurônios sempre proporcional ao tamanho do cérebro.