The December issue of the American Psychological Association‘s Monitor on Psychology is now online. This month’s Time Capsule section features a piece, “Lessons from Bird Brains,” by Cathy Faye on the work of Eckhard Hess on imprinting. Faye writes,

In the 1950s, Hess and A.O. Ramsay, a high school biology teacher from Maryland, began studying imprinting in the laboratory with papier-mâché mallard ducks fitted with off-center wheels that mimicked waddling. The researchers created a great variety of model ducks to experiment with, including ducks with moving heads and ducks with built-in heaters.

By means of pulleys and cords operated from a distance, Hess and his colleagues released newly hatched ducklings from a small cardboard box. The model duck would emit a sound — either a tape-recorded duck call or a human mimicking one — and move around a runway via a motorized arm. Levers on the runway floor kept track of the ducklings’ steps to measure their following behavior. At the end of the experiment, a trap door in the runway’s floor returned the ducklings to their box.

The full piece can be read online here.