Response acquisition by zebrafish (Danio rerio) with delayed reinforcement.

Abstract

Zebrafish (Danio rerio) is a common vertebrate animal model in biomedical research and is a promising species for studying how genes interact with environmental factors in determining behavior. The present study investigated how reinforcement parameters affect zebrafish behavior by assessing response acquisition with delayed reinforcement, which has been studied with other species (e.g., rats, pigeons, humans, etc.) but not with zebrafish. Twenty-four experimentally naïve subjects were exposed to a tandem fixed-ratio 1 differential-reinforcement-of-other-behavior x-s schedule of reinforcement, where x varied across subjects. There were six different delay-to-reinforcement durations and sets of four fish were assigned to each delay duration. All of the fish assigned to a 0-, 0.5-, or 1-s delay acquired responding. Two fish acquired responding with a 3-s delay and one fish appeared to have acquired it with a 6-s delay although the latter result was less clear. None acquired responding with a 12-s delay. These results suggest that zebrafish behavior is sensitive to delays to reinforcement and the time frame over which reinforcement is effective may be limited approximately to 6 s. This time frame is shorter than that found with other species. Practical and theoretical implications of the present finding are discussed.