At a World's Fair early in this century, one of the featured attractions was a new concept, which today is used in zoos all over the world —the open-air bear and lion pits. Large, natural settings had been built into the hillside, reproducing the animals' natural habitat. A moat and a fence separated the viewers from the animals. ... Previously the animals had been enclosed in indoor cages with iron bars. They had paced somberly around the rectangular cages four steps by eight steps, four steps by eight steps, around and around the cage. The zookeepers and the fair officials eagerly awaited the great day when the animals would be released into the open hillside settings where they could frolic unrestricted.
Finally, freedom day arrived, and the fair officials assembled in front of the new animal pits to watch while the keepers released the animals. The bears, the lions, and the tigers, each in their individual areas, walked in, sniffed the air, looked around, and then very somberly began to pace four steps by eight steps, four steps by eight steps, in imaginary cages in the middle of these large enclosures.
What was happening? Although the animals' physical surroundings had been enlarged many times over, mentally they were imprisoned by the small-cage habit. Eventually, however, they discovered that they now had ample space, and they broke out of that small-cage habit and were able to enjoy this generous provision.
