The present study assessed the role of preparatory responses on observing-response contingencies. Six water-deprived rats were exposed to discrete trials that could end with or without water presentation. Observing responses produced discriminative stimuli of the current trial. Across experimental conditions, two dippers with different working mechanisms alternated. In one of them, but not in the other, access to water was temporally restricted. Supposedly, the temporal restriction would increase the occurrence of preparatory responses that led subjects to maximize water consumption. Results showed that dipper mechanisms affected the occurrence of responses in the presence of the discriminative stimuli, but not in their production. In general, there was a higher number of responses under the stimulus signaling absence of water, particularly when the time-restricted dipper was installed.