Lever-contact responses in rats: automaintenance with and without a negative response-reinforcer dependency.

Pairing the presentations of one lever (cueing lever) with food led to the acquisition and persistence of lever contacts by rats. This behavior did not occur with a second lever, which was presented randomly with regard to food delivery. This finding obtained whether food delivery was independent of cueing-lever contacts (positive automaintenance) or dependent on the absence of cueing-lever contacts (negative automaintenance). The general findings were: (1) cueing-lever contacts on the positive automaintenance procedure occurred on a higher proportion of trials and at higher rates when contacts occurred than on the negative automaintenance procedure; (2) instances of the cueing lever's failure to support responding were more frequent on the negative than the positive automaintenance procedure; and (3) the topography and median contact duration of positively automaintained responding differed from negatively automaintained responding. These findings agree substantially with the automaintenance literature on pigeons, suggesting that similar processes may characterize automaintained responding in both pigeons and rats.