A quantitative analysis of the effects of qualitatively different reinforcers on fixed ratio responding in inbred strains of mice

- Three inbred mouse strains (BALB/c, C57BL/6, DBA/2) responded on fixed-ratio schedules of reinforcement.
- The effects of two qualitatively different reinforcers on response rate were assessed.
- Response rates were higher for milk compared to sucrose pellets on moderate ratios.
- The responding of inbred mice is sensitive to reinforcer type.