The effects of 100 dB 1-kHz and 22-kHz tones as punishers on lever pressing in rats

Aversive control is an important yet understudied process of learning. One reason aversive control may be relatively understudied is ethical concerns about painful stimuli (e.g., electric shock). High decibel broad-band noise and 22-kHz vocalizations both demonstrably affect rodent behavior while not necessarily being painful. The goal of this study was to determine if 100-dB 22-kHz-pure tones were differentially more effective in reducing operant response rates in rats. We examined whether 22-kHz pure tones would function as aversive stimuli, specifically as positive punishers. The effects of response-dependent as well as continuously presented 22-kHz and 1-kHz tones on rate of response maintained by variable interval 30-s food deliveries were assessed across several conditions. We found that response rates were lower when tones were presented response dependently than when tones were presented continuously throughout a session. We also found that the lower response rates obtained with response-dependent 22-kHz tones were not significantly different from response rates obtained with response-dependent 1-kHz tones. The primary conclusion of this experiment is that both 1-kHz and 22-kHz tones functioned as punishers, but that the 22-kHz tones were not differentially more effective in reducing response rate.