AbstractsPsychology

The animals used in the present experiments were male hooded rats from the Royal Victoria Hospital Colony. They were from 19 to 21 days old when obtained. The rearing conditions were modeled after those of Hymovitch (1952). The “free environment” was a wooden box (30 x 60 x 6 in.) with a wire screen top. It contained a tunnel, barriers, blocks, and elevated runways. The restricted environment cages were made of stave-pipe 15 in. high and 8 in. in diameter; holes at the top and bottom admitted light and ventilation without permitting vision of the outside surroundings. A single rat lived on a wire screen floor placed about one inch above the lower openings.