Automated preference testing apparatus for rating palatability of foods

An electronic preference testing apparatus is described for measuring taste preference of rodents and other small animals with solid or liquid foods. The apparatus is designed on the principle of the two-choice, preference technique. It operates photoelectrically with a sequence of presentations so that whenever a subject eats from a compartmentalized food tray, a standard and a test food are each briefly sampled alone before both foods are presented together (in alternate positions) for preference determination. Preferences are automatically recorded on digital counters. The apparatus is built in two modules (a preference tester and the master control) connected by multiconductor cable. The modular design provides portability and isolation of the animals from the major noise-producing components. Diagrams of the apparatus are given, and test results from a trial that evaluated positional bias and a sucrose-concentration preference experiment are presented to demonstrate its application in research.     

A comparison of escape and avoidance conditioning in wild and domesticated rats

In the first of two experiments, three cotton rats (Sigmodon hispidus) and three albino rats were exposed to instrumental escape, unsignaled avoidance, and signaled avoidance, in that order. All subjects learned the escape procedure quickly, with the albino rats having generally shorter latencies, higher response rates, and requiring fewer sessions to reach the criterion. When the avoidance contingency was introduced, the cotton rats continued to respond almost entirely in the presence of the shock, whereas the albino rats responded in its absence, thus displaying effective avoidance behavior. Introduction of a pre-aversive stimulus did not improve the performance of the cotton rats. In the second experiment, five cotton rats and four albino rats were exposed to a free-operant (Sidman) avoidance procedure with a shock-shock interval of 3 sec and a response-shock interval of 20 sec. The cotton rats initiated responding at lower shock intensities than the albino rats, but their asymptotic avoidance responding was far less effective.     

A contribution toward interbehavioral analysis I. Some general concepts

The Psychological Record -