Attraction to odors in hamsters: an evaluation of methods

Six different attraction tasks (one stimulus presented at a time) and five preference tasks were compared. In five of the six attraction tasks, one stimulus (vaginal secretion) was sniffed by males longer than any other stimulus, but the degree of difference between the stimulus and the others, and the relative attractiveness or aversiveness of the other stimuli, varied greatly across methods. One method was not useful for demonstrating differences in attraction to positive neutral odors but was useful for demonstrating aversions. In the preference tasks females demonstrated a significant preference for the odors of intact males over those of castrated males in four of the five methods, and again the strength of the preferences differed across methods. It is suggested that preference tasks are more sensitive and less subject to variability due to details of the method employed than are attraction tasks. Procedures in which the test animal's own home cage was used as the testing environment tended to emphasize effects due to novelty rather than the inherent attractiveness of the odorants. It is suggested that the use of novel objects as sources for test odors and the use of airstreams for delivery of odors reduce the salience of the test odorants.