Behavioral bias and left-right response differentiation in the rat

To examine the proposition that lateral asymmetry facilitates left-right response differentiation in rats, we examined the relationships between the strengths of several behavioral biases and the scores on a learning task requiring left-right response differentiation. No support was found for a simple model positing a monotonic relationship between any behavioral bias and the learning scores. However, performance showed a U-shaped relationship to one behavioral bias. This finding conforms to a curvilinear model in which rats at either extreme of asymmetry are disadvantaged, at low degrees of asymmetry by a lack of navigational reference, and at high degrees by resultant strong position habits; moderately asymmetrical rats have neither disadvantage and are best able to use the asymmetry as a reference in processing left-right information.