A rapid response acquisition model for mice contrasting different strains for the acquisition of a food motivated nosepoke response has been described recently (Baron and Meltzer, SFN 25:641, 1999). In that study, 129SvJ and DBA2J mice took a longer time to reach a set number of correct responses compared with CD1 mice. Measures based on latency can be misleading since motoric difference may influence latency. The current study contrasts different strains of mice (DBA2N, CD1, 129SvEv, C57BL6/N) in the acquisition of a nosepoke response employing a response based criterion measure for learning. Mice, restricted to 85% of their initial weight, were evaluated over a four day period. On day 1, 2 hrs of non-contingent presentation of an evaporated milk reward was paired with a houselight on a variable interval 60 sec schedule. On day 2, one of 2 illuminated nosepokes was randomly assigned as correct and reinforced, whereas responses in the other nosepoke were only recorded. The session was terminated when a sub...