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.
Då det var baserat på få bevis, trodde forskare att alla däggdjurshjärnor inklusive den mänskliga hjärnan, var byggda på samma sätt, med ett antalet neuroner som var proportionell med storleken på hjärnan.