The Effects of Hippocampal and Area Parahippocampalis Lesions in Pigeons: I. Delayed Matching to Sample

Four experiments were conducted to determine the effects of bilateral damage to the hippocampus and area parahippocampalis (Hp-APH) on visual memory in pigeons using the delayed matching-to-sample (DMS) procedure. In Experiment 1, we generated visual retention gradients with delays of 0, 1.5, 3, 6, and 12 sec both preoperatively and postoperatively in three pigeons with considerable preoperative visual DMS experience. Bilateral Hp-APH lesions had no effect whatsoever on visual retention. In Experiment 2, we examined the effects of Hp-APH lesions on both the acquisition of a visual DMS task with a 0-sec delay, and the subsequent retention performance with delays of 0, 3, 6, 12, and 24 sec. There was no difference between unoperated control pigeons and Hp-APH pigeons either in terms of the number of sessions required to learn the visual DMS task or in terms of their subsequent visual retention performance levels. In Experiments 3 and 4, we examined whether Hp-APH pigeons might be more sensitive than control pigeons to the effects of proactive interference (by reducing the duration of the intertrial interval) and retroactive interference (by introducing delay-interval illumination). Although reducing the duration of the intertrial interval and increasing the level of delay-interval illumination both resulted in lower performance levels on the visual DMS task, there was no indication that the Hp-APH pigeons were any more affected by the changes in interference levels than were unoperated control pigeons. These findings support the view that the Hp-APH in pigeons plays little role in the processing and retention of purely visual information.     

Water use scenarios assessment using multicriteria analysis

Water management is a fertile terrain for research, and can be investigated using several methodological instruments and approaches. Multipurpose water resources, which allow for the contemporary presence of in‐stream (fishing, swimming, etc.) and off‐stream uses (agriculture, household, etc.), are particularly difficult to management due to increasing water demand and the conflict between consumptive and not consumptive uses. New scenarios in agricultural policy (Reform of the European Common Agricultural Policy) and new requests from local stakeholders (recreational activities, rising household water demand, etc.) involve use of decision support methods to find a balance between multiple potential uses. This study describes the application of multicriteria decision aid for choosing the best project for water management and local development among a set of alternatives, using the regime method. The regime method can integrate quantitative data with quality judgement and preference index. The study aims to verify if the regime approach is understandable for the decision maker and if it is suitable for use in ambiguous situations where no quantitative information is available. It is not always possible to get the ‘best alternative’ in multicriteria evaluation: in this study we found two top‐rank alternatives, with minor differences, to submit to the decision maker. Copyright © 2011 John Wiley & Sons, Ltd.     

The Scarcity Bias

Two experiments provided empirical support for the scarcity bias, that is, when the subjective value of a good increases due to the mere fact that it is scarce. We define scarcity as the presence of limited resources and competition on the demand side (i.e. not enough for two people). In Experiment 1, 180 students were divided into two conditions. The same good was abundant in one condition but scarce in the other one. The scarcity condition involved a partner (competitor) to create scarcity, while the abundant condition did not. Results showed that more participants chose a good when it was scarce than when it was abundant, for two out of four sets of items (ballpoints, snacks, pencils, and key rings). Experiment 2 employed 171 participants and a WTA (willingness to accept) elicitation procedure of the subjective value of the good. Results showed that the scarce good was given a higher WTA price by those participants choosing it, than by those who did not, compared to the WTA of the abundant good, despite the fact that both types of participants assigned a lower market price to the scarce good, as compared to the abundant one. Deux expériences ont confirmé empiriquement le biais de rareté (la valeur subjective d'un bien s'accroît en raison de sa seule rareté). La rareté est définie par une demande conflictuelle car confrontée à des ressources limitées (tout le monde ne pourra pas être satisfait). La première expérience fit appel à 180 étudiants répartis sur deux conditions. Le même bien était abondant dans l'une des conditions et rare dans l'autre. La condition de rareté impliquait la présence d'un concurrent pour créer la pénurie, concurrent inexistant dans la condition d'abondance. Les résultats ont montré que davantage de participants se sont portés sur un bien quand il était rare que lorsqu'il était abondant, cela pour deux des quatre séries d'items (stylos à bille, casse‐croûte, crayons, porte‐clefs). 171 sujets participèrent à la seconde expérience qui utilisa une procédure de mise en évidence de la valeur subjective du bien (WTA: prix jugé acceptable pour se procurer le bien). Il apparaît que le bien rare bénéficiait de la part de ceux qui le choisissait d'un prix WTA supérieur à celui octroyé par ceux qui le délaissaient, par comparaison au WTA du bien abondant, et cela en dépit du fait que les deux catégories de sujets accordaient un prix de vente inférieur au bien rare par rapport à celui qui était largement disponible.