Reliable operant apparatus for fish: Audio stimulus generator, response button, and pellet-dispensing nipple

Abstract

As part of ongoing research into the ability of koi to categorize complex auditory stimuli, we have had to develop novel apparatus, The stimulus generator presents sound from two CD drives under computer control through a new underwater speaker. The operant manipulandum is a horizontal button that eliminates spurious triggering by water turbulence and problematic response topographies. The button's design has also been adapted for use by tilapia in an aquacultural food-preference study. The feeder uses a nipple to dispense food pellets reliably under water. In this paper, the apparatus is described in detail. Also discussed are methodological issues related to its design, as weIl as its usage in a pilot study in which koi learned to discriminate music from silence by using a single manipulandum with food reinforcement.We have been studying the ability of fish-specifically koi (Cyprinus carpio)-to discriminate and categorize complex auditory stimuli such as music. In this paper, we describe both the apparatus that we have developed and a preliminary experiment that demonstrates the use of the apparatus and illustrates some methodological issues. In designing the apparatus, we were guided by ethological as weil as practical considerations.In designing our aquarium, we were influenced by the fact that koi are social animals. Living in isolation can be stressful in itself, but transportation between a horne tank and a separate experimental tank can be stressful and experimentally impractical, especially once fish have grown to a length of more than a foot and a weight of several pounds. Therefore, our aquarium consists ofa group horne tank that can be partitioned into experimental and holding areas.We also developed a response button and feeder because we needed reliable equipment.

Perceptual Processes and the Maintenance of Polymorphism Through Frequency-dependent Predation

“…automated reward dispensers) may pose challenges but there already exist some mechanical devices (e.g. Chase and Hill, 1999) that could be modified for experiments on (visual) detection of prey. Taken together with experimental demonstrations of frequency-dependent predation and observed levels of guppy polymorphism in nature, evidence of search image would provide strong support for the notion that individual predator behaviour can maintain polymorphism.…”

Music discriminations by carp (Cyprinus carpio)

“…As is shown in Figure 3, Beauty and Oro met this standard within the first few sessions. The characteristically hyperactive Pepi went 13 sessions before his first S trial, during which he did not respond at all, but otherwise from the start he was much like the other subjects in exhibiting downward trends in the average number of responses per S trial and in the percentage of his total responses that occurred during S (Chase & Hill, 1999).…”

“…The fish apparatus was novel and was developed in my laboratory. Its rationale, design, and construction have been described in detail elsewhere (Chase & Hill, 1999). During experimental sessions, the home aquarium was divided by a clear partition into an experimental chamber and a holding area, and the noisy aeration system was turned off.…”

“…The processes of magazine training and of familiarization with the response button, the stimulus presentation system, and the rest of the apparatus are described in detail in Chase and Hill (1999). Before conducting the genre discrimination experiment, it was necessary to test the novel apparatus and the intended discrimination protocol.…”

“…The subjects were given a simple discrimination task-namely, sound versus silence-which is described in detail in Chase and Hill (1999). The procedure presented randomly timed intervals (typically between 40 and 90 sec) of music (S+) and silence (S ) in alternation, and reinforced each response that was made in the presence of music with food.…”