Perceptions of Liver Transplant Candidates with or Without an Alcohol Use History

Cirrhosis secondary to alcohol use is a primary cause of liver disease and a medical condition for which liver transplantation is a viable treatment option. However, there remains considerable debate within both the lay and the medical communities regarding the distribution of a scarce medical resource to adults with alcoholism. This study examined college students' perceptions toward an adult, presented in a written vignette, for whom liver transplantation was medically indicated. The influence of gender (female and male) and alcohol use history (no alcohol history, alcoholism history with long-term abstinence, alcoholism history with current use) on these ratings was examined. Subjects rated the adult presented with no alcohol history more positively than they did the adults presented with a history of alcoholism. Also, the adult with no alcohol history was more likely to be offered transplantation and was given higher priority ratings for transplantation by subjects. While subjects' own alcohol use history and organ donor registration status were not associated with ratings, having a family member with an alcohol problem and personally knowing a transplant recipient were related to more favorable ratings toward the adult presented in the vignette. Implications of these findings as well as limitations of the study are discussed.     

Noticing and responding in a discrimination based on a distinguishing element

In learning a successive go/no-go discrimination between a positive display consisting of the elements A and B, and negative display consisting of A-alone, pigeons first trained to peck A shift to pecking the distinguishing B element. In order to learn whether or not the shift to B is facilitated by B's function as a signal of the reinforcer, apart from the direct reinforcement of B responses, six arrangements of the elements with respect to the food reinforcer were used. Discrete trials were terminated by a single peck or after 4 sec. The A and B elements were dots of different color. The most critical comparison was between two groups, both of which received no reinforcement for a response directed to B. In one case, B signaled the reinforcer: An A response was reinforced when B was present but not when A appeared alone. In the other, B signaled the absence of a reinforcer: An A response was nonreinforced when B was present, while the response to A-alone was reinforced. During training and in extinction many more reponses were made to B when it signaled the reinforcer than when it signaled its absence. It is concluded that in a discrimination between AB positive and A negative the shift from pecking A to pecking B is facilitated by B's role as a signal for the reinforcer even on trials in which the peck is not made to B. Results from certain other groups showed that, unless pecks shifted to B within the positive display, pecks to A continued on the negative, A-alone trials as well as on the positive AB trials.