Development of a single-code/default coding strategy in pigeons

We tested the hypothesis that pigeons could use a cognitively efficient cod ing strategy by training them on a conditional discrimination (delayed symb olic matching) in which one alternative was correct following the presentat ion of one sample (one-to-one), wheras the other alternative was correct fo llowing the presentation of any one of four other samples (many-to-one). Wh en retention intervals of different durations were inserted between the off set of the sample and the onset of the choice stimuli, divergent retention functions were found. With increasing retention interval, matching accuracy on trials involving any of the many-to-one samples. The data suggest that rather than learning each of the five sample-comparison associations indepe ndently, the pigeons developed a cognitively efficient single-code/default coding strategy.