Evidence for common coding of temporal and nontemporal information in pigeons

Two experiments found evidence that pigeons commonly code temporal and visual samples that are associated with the same comparisons in many-to-one matching. In Experiment 1, pigeons were trained to match temporal (2-sec and 8-sec keylight durations) and color (red and green) samples to line tilt comparisons (vertical and horizontal). Similar rates of forgetting were found for all samples. Furthermore, retention of sample information appeared more similar for samples which shared common comparisons than those that did not. In Experiment 2, pigeons learned new comparison (circle and triangle) associations with either temporal or visual samples from Experiment 1. When tested on their ability to match the remaining samples to the new comparisons pigeons showed immediate transfer effects. Results of both experiments provide strong evidence that pigeons form common codes between temporal and visual information. Encoding of temporal information in many-to-one matching is discussed in terms of a categorical coding model.