An automated positive reward method for measuring acoustic sensitivity in fish

A microcomputer-controlled positive reward operant conditioning paradigm was developed to measure auditory sensitivity of the goldfish (Carassius auratus). Although other procedures have been used to measure hearing sensitivity in fish, all earlier studies have been done with some form of aversive conditioning. Goldfish were trained with a positive reinforcement method to determine hearing thresholds at 200, 500, 1000, 1500, and 2000 Hz. The audiogram obtained in this study is in close agreement with thresholds obtained with instrumental avoidance and classical conditioning procedures involving negative reinforcement (shock). The similarity in threshold data validates the effectiveness of the positive reinforcement paradigm described here. The major advantages of the present paradigm are the following: (1) No physical punishment such as electric shock is used, and (2) the versatility of the system allows easy modification for a variety of experiments.