Habituation of motion sickness in the cat

We subjected 30 female cats to a motion sickness stimulus in three series of tests. A series consisted of five tests given bi-weekly, weekly, or daily. Each test consisted of 30 min of stimulation followed by 1 min of rest, and series were separated by a period of not less than 14 d. Retching was the dependent variable. No habituation (reduction in the incidence of retching) was found with biweekly testing but pronounced habituation was observed with weekly and daily testing. The 30 cats were divided evenly into high and low susceptibility groups based on the results of the biweekly tests. The rate of habituation was the same for the two susceptibility groups in both the weekly and daily series.