If you give a mouse a light-switch

As no-one has posted here for a while, I thought I'd share a passage
from a book I've been reading: When Elephants Weep - The Emotional
Lives of Animals, by Jeffrey Moussaieff Masson and Susan McCarthy.

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Zoologist J. Lee Kavanau gave white-footed mice (deer mice) the
opportunity to adjust light levels in their cages by pressing a lever.
He found that the mice preferred dim light to bright light or darkness,
and if left alone would adjust the light accordingly. But if he turned
the lights up high the mice would frequently respond by making the cage
completely dark. Conversely, if he made the cage completely dark, the
mice would make the light as bright as possible. He also found that if
he disturbed sleeping mice, so that they came out of their nest boxes
to investigate, they would soon go back inside, but if he put them
inside by hand, they would immediately come out, no matter how many
times he replaced them. They cared about choice more than comfort. When
given the opportunity to manage their environment, they battled fiercly
for control. Because wild white-footed mice have far more control over
their surroundings and activities, this matters more to a captive
animal. Even if a zoo animal is supplied with all the material wants,
there may be something vital lacking, something it needs to be happy.
One of the joys of freedom may simply be the ability to evade
compulsion.