[Eli5] what’s the meaning of the ratio brain size/body mass? Why a bigger brain isn’t alone a sign of bigger intelligence? What has body mass to do with it?
In: Biology
Imagine that you took a human and made them half as tall. Their brain is also going to be half as big (technically it might be less, since square/cube law), but the ratio between the size of their brain and the size of their body would remain the same. And, indeed, we see that people with dwarfism who have smaller skulls and smaller brains are just as intelligent as everyone else.
This leads to a quandary: why are humans intelligent? Obviously a whale is going to have a bigger brain than a human. A blue whale’s brain might weigh more than an entire human body! But the whale is not dozens of times more intelligent than a human (that we have observed, but we can’t be totally sure). So being intelligent isn’t just a function of how big your brain is, but instead might be about the size of your brain relative to the rest of your body. Or, in other words, you don’t just want a big brain in absolute terms, but a big brain to body mass ratio.
Latest Answers