Ultrasonic calling during fear conditioning in the rat: no evidence for an audience effect

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2008.04.017 Byline: Markus Wohr, Rainer K.W. Schwarting Abstract: Rats, Rattus norvegicus, produce 22kHz ultrasonic vocalizations in aversive situations such as during exposure to cats or fear conditioning. These calls are considered to be part of the animal's defensive repertoire and might serve as alarm signals for conspecifics. The aim of the present study was to test whether the production of 22kHz calls is affected by the social context during fear conditioning. Animals were tested in one of three experimental conditions: either alone, with an anaesthetized conspecific, or with an active conspecific. In line with the hypothesized alarming function of 22kHz calls, we expected the presence of a conspecific to potentiate the production of 22kHz calls. The results, however, show that the production of 22kHz calls during fear conditioning is clearly not potentiated by the presence of a conspecific; if at all, its presence had a mild attenuating effect on call rate. Also, call characteristics were similar in all three experimental conditions. Therefore, our findings do not support the hypothesis that the sender actively produces 22kHz calls to warn conspecifics about danger. Author Affiliation: Experimental and Physiological Psychology, Philipps-University of Marburg, Germany Article History: Received 20 February 2008; Revised 26 March 2008; Accepted 29 April 2008 Article Note: (miscellaneous) MS. number: D-08-00104