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Transitive inference (TI) has been studied in humans and several animals such as rats, pigeons and fishes. Using different methods for training premises it has been shown that a non-trained relation between stimuli can be stablished, so that if A > B > C > D > E, then B > D. Despite the widely reported cases of TI, the specific mechanisms underlying this phenomenon remain under discussion. In the present experiment pigeons were trained in a TI procedure with four premises. After being exposed to all premises, the pigeons showed a consistent preference for B over D during the test. After overtraining C+D- alone, B was still preferred over D. However, the expected pattern of training performance (referred to as serial position effect) was distorted, whereas TI remained unaltered. The results are discussed regarding value transfer and reinforcement contingencies as possible mechanisms. We conclude that reinforcement contingencies can affect training performance without altering TI.

The ambiguous-cue task is composed of two-choice simultaneous discriminations involving three stimuli: positive (P), ambiguous (A), and negative (N). Two different trial types are presented: PA and NA. The ambiguous cue (A) served as an S- in PA trials, but as an S+ in NA trials. When using this procedure, it is typical to observe a less accurate performance in PA trials than in NA trials. This is called the ambiguous-cue effect. Recently, it was reported in starlings that the ambiguous-cue effect decreases when the stimuli are presented on an angled (120°) panel. The hypothesis is that the angled panel facilitates that the two cues from each discrimination are perceived as a compound, precluding value transfer via a second-order conditioning mechanism. In this experiment, we used pigeons and a flat panel. Nevertheless, our data were quite similar to the previous data in starlings. We conclude that the form of the panel cannot explain the ambiguous-cue effect. Several alternatives to be explored in future experiments are suggested. The riddle of the ambiguous-cue problem still remains unsolved.

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Este artículo puede ser impreso, descargado y distribuido libremente. Citarlo de la siguiente manera: Alfaro, L., García-Leal, O., & Cabrera, R. (2010) Estrategias de búsqueda y consumo de alimento en grupos de ratas expuestos a diferentes distribuciones de alimento. Revista Mexicana de Análisis de la Conducta, 36, 2.Este es un artículo de acceso libre distribuido bajo los términos de la licencia de atribución Creative Comons (http://creativecommons.org/licenses/by/2.0), que permite el uso irrestricto, distribución y reproducción mediante cualquier medio, siempre y cuando se cite apropiadamente el trabajo original.Este proyecto de investigación fue posible gracias a que Rosalva Cabrera disfruta de año sabático