Brain food.

Salmon for lunch today.
It is a truth universally acknowledged that eating oily fish regularly has good health benefits.
But there is also a widely held belief that eating fish is good for the brain.
Certainly in 1946 on the day before I sat the 11+ examination my mother insisted that I ate large quantities of fish.
It worked and I passed the exam to go to the Grammar School. But demonstrating a specific link would I think be rather difficult.