Scientists performed an experiment to determine whether there is a connection
between learning ability and food. They took two groups of 20 mice each, all
from the same purebred strain. The mice were deprived of food for 3 days and
then given a standard learning session in running through a maze. They were
trained by giving them a mild electric shock whenever they took a wrong turn.
Immediately after each learning session, one group of mice was fed, but the
other was not, A week later, all of the mice were tested to see whether they
could still run the maze correctly. The group that had been fed had retained
this ability, but the other group had not.