50-kHz chirping (laughter?) in response to conditioned and unconditioned tickle-induced reward in rats: effects of social housing and genetic variables.
“In these studies the incidence of conditioned and unconditioned 50-kHz ultrasonic vocalizations (USVs) in young rats was measured in response to rewarding manual tickling by an experimenter. We found that isolate-housed animals vocalize much more then socially housed ones, and when their housing conditions are reversed, they gradually shift their vocalization tendencies… …We successfully bred for high and low vocalization rates in response to tickling within four generations. The high tickle line showed quicker acquisition of an instrumental task for, as well as less avoidance of, tickling as compared to the random and low tickle lines.”
Thanks to Neuroskeptic for today’s ROFL! Check out his blog for more info and a cute movie about rat tickling.