Operant conditioning in the guinea pig.

A technical note to this journal (Berryman, 1976) is the most recent of several reports distributed over the last 50 yr which suggest that the guinea pig demands uinusual treatment, relative to that accorded more familiar subjects of behavioral research, if it is to be employed in operant conditioning studies. The inordinate time investment, frequent behavioral instability, and the general recalcitrance of the animal reported by those few investigators successful in training the guinea pig to perform simple operants, has led some to question the viability of the species as a standard behavioral preparation (eg., Jonson, Lyle, Edwards, and Penny, 1975; Valenstein, 1959). In contrast, we have found that the guinea pig can be readily trained as a reliable observer in a relatively demanding psychophysical task for determining absolute auditory thresholds. The final testing procedure is a variant of the basic methods used in our laboratory (Moody, Beecher, and Stebbins, 1976). Two transluscent Gerbrands pigeon response keys are located on one wall of a 25.4-cm by 25.4-cm by 25.4-cm testing chamber constructed of 0.6-cm hardware cloth. The keys are mounted 3.8 cm above the floor of the chamber, 11.5 cm apart. The chamber is mounted on a portable cart and the entire assembly is contained within an Industrial Acoustics double-walled sound-insulated booth during testing. The guinea pig repeatedly pushes on the illuminated left key (the observing disk) with its nose. Response feedback is provided by a 50-msec darkening of the observing disk following each nose press that exceeds 0.14N. After a variable period of time, a response on the observinig disk is followed by a 3-sec tone presentation from a transducer mounted on the chamber ceiling directly over the observing disk. A nose press on the lighted right-hand key (the reporting disk) during the tone results in delivery of a Noyes formula D 45-mg food pellet to a tray located midway between the keys and projecting into the experimental space. Report responses in the absence of a tone result