Exchange delays and impulsive choice in adult humans.

Choice responding by adult humans in a discrete-trial task was examined as a function of conditions that manipulated either the delay to point delivery or the delay between points and their exchange for money. In point-delay conditions, subjects chose between an "impulsive" alternative that provided a small amount of points immediately and a "self-control" alternative that provided a larger amount of points delayed by 15, 30, or 60 s. Points were exchanged for money immediately following the session. Subjects preferred the self-control alternative. In exchange-delay conditions, subjects chose between a small amount of points exchangeable for money immediately following the session and a larger amount of points exchangeable for money after 1 day, 3 weeks, or 6 weeks. A self-control preference observed for all subjects in the 1-day exchange-delay condition reversed to exclusive impulsive preference for 4 of the 6 subjects when choice conditions involved exchange delays of 3 or 6 weeks. These results show that human choice is sensitive to the manipulation of exchange delays and that impulsive preference can be obtained with exchange delays on the order of weeks.     

Token reinforcement, choice, and self-control in pigeons.

Pigeons were exposed to self-control procedures that involved illumination of light-emitting diodes (LEDs) as a form of token reinforcement. In a discrete-trials arrangement, subjects chose between one and three LEDs; each LED was exchangeable for 2-s access to food during distinct posttrial exchange periods. In Experiment 1, subjects generally preferred the immediate presentation of a single LED over the delayed presentation of three LEDs, but differences in the delay to the exchange period between the two options prevented a clear assessment of the relative influence of LED delay and exchange-period delay as determinants of choice. In Experiment 2, in which delays to the exchange period from either alternative were equal in most conditions, all subjects preferred the delayed three LEDs more often than in Experiment-1. In Experiment 3, subjects preferred the option that resulted in a greater amount of food more often if the choices also produced LEDs than if they did not. In Experiment 4, preference for the delayed three LEDs was obtained when delays to the exchange period were equal, but reversed in favor of an immediate single LED when the latter choice also resulted in quicker access to exchange periods. The overall pattern of results suggests that (a) delay to the exchange period is a more critical determinant of choice than is delay to token presentation; (b) tokens may function as conditioned reinforcers, although their discriminative properties may be responsible for the self-control that occurs under token reinforcer arrangements; and (c) previously reported differences in the self-control choices of humans and pigeons may have resulted at least in part from the procedural conventions of using token reinforcers with human subjects and food reinforcers with pigeon subjects.     

Ecology, Community, and AIDS Prevention

I explore the role that may be played by an ecological view of AIDS prevention and AIDS-related social concerns. The study of AIDS risk behavior and interventions designed to prevent AIDS have challenged Health Psychology's typically individualistic perspective. Issues of empowerment, psychological sense of community, interpersonal ties, resources, and culture are central to an understanding of risky sexual behavior and helping people to guard themselves from the threat of AIDS. However, despite Community Psychology's historical expertise in these areas, the field has only recently become involved in AIDS prevention efforts. I outline how resource-based, ecological theories may prove more helpful in addressing the AIDS pandemic than the individual, cognitive theories that have typically been adopted. Sexual behavior and associated risk are tied not simply to people's personal behavior and thoughts but to the likelihood of disease exposure in their ethnic group, the power and choices associated with power in that group, and the alternative means available of meeting their overall sexual, romantic, economic, and social goals. As such, AIDS research and intervention must simultaneously address the individual, social, and cultural spheres if insights that can translate to meaningful change can be expected to occur.     

Should a criminal receive a heart transplant? Medical Justice vs. Societal Justice

Should the nation provide expensive care and scarce organs to convicted felons? We distinguish between two fields of justice: Medical Justice and Societal Justice. Although there is general acceptance within the medical profession that physicians may distribute limited treatments based solely on potential medical benefits without regard to nonmedical factors, that does not mean that society cannot impose limits based on societal factors. If a society considers the convicted felon to be a full member, then that person would be entitled to at least a “decent minimum” level of care — which might include access to scarce life-saving organs. However, if criminals forfeit their entitlement to the same level of medical care afforded to all members of society, they still would be entitled to a kind of “rudimentary decent minimum” granted to all persons on simple humanitarian grounds. Almost certainly this entitlement would not include access to organ transplants.     

Stress,coping resources,and injury risk

Over the last two and a half decades, researchers have tried to determine if psychological variables predispose or buffer athletes from injury. They have found that sport participants who experience many recent stressors, and who do not have the resources and skills to cope with the stress, seem most at risk for injury. This article reviews that research as well as efforts to identify mechanisms that might explain why the stress-injury relationship occurs and interventions that will hopefully reduce the injury risk. Because the multicomponent stress-injury model of Andersen and Williams (1988) helped provide the impetus and theoretical base for much of that research, it serves as the foundation for organizing and summarizing the findings. Although the research has focused largely on sport injuries, the findings have relevance for understanding and potentially preventing many accidents and injuries that occur outside the realm of sport participation.     

THE EFFECTS OF A GOOD-BEHAVIOR CONTRACT ON THE CLASSROOM BEHAVIORS OF SIXTH-GRADE STUDENTS1

The effects of a good-behavior contract on the on-task behavior, disruptive behavior, daily assignment completion, and weekly grades of four sixth-grade students were examined in a public school classroom. The contract consisted of presenting the students with a list of good conduct and assignment completion goals and a list of disruptive behaviors coupled with a list of rewards and penalties that could be earned. The rewards and penalties made use of existing facilities and classroom privileges. At the beginning of each morning work period, the teacher negotiated the good-behavior contract with each experimental subject. During the negotiations, the teacher emphasized student self-management and encouraged each student to earn a reward by achieving the good-conduct goals and completing the contract assignments. An isolated work area was provided to allow students the opportunity to remove themselves from their desks for a fixed period of 15 min. At the end of the work period, the teacher determined whether each student earned a choice of reward or penalty dependent on assignment completion and whether the teacher had observed disruptive behaviors. Thus, the contract permitted the student to negotiate the goal behaviors and contingencies with the teacher. Throughout the study, the students were in agreement with the teacher on whether a choice of reward or penalty had been earned. The contract was introduced for different children at different times, constituting a multiple-baseline analysis. On-task behavior and daily assignment completion increased, weekly grades were higher, and disruptive behavior decreased when the contract was in effect. Three contrast subjects were selected from the class as model students who consistently produced acceptable assignments and who did not engage in high rates of disruptive and/or off-task behaviors. When the contract was in effect for the experimental subjects, their performance compared favorably with the contrast subjects, who never received the daily contract. The results demonstrated that the contract was effective within the confines of the facilities and contingencies readily available in a public school classroom setting.     

Self-reinforcement

Self-reinforcement in operant situations generally refers to those arrangements in which the subject delivers to himself a consequence, contingent on his behavior. However, it is noted that the definition of all other types of reinforcement make its delivery contingent on the subject's behavior. What is actually at issue is the agent who defines whether or not the response required for reinforcement has been met. In self-reinforcement, the subject himself defines this. In the laboratory, this requirement is machine-defined; in school examinations, it is teacher-defined; and in many clinical self-control situations, it is also independently defined. A reinforcement contingency presupposes such independence, absent in self-reinforcement. Implications for research and practice are discussed and alternative formulations are offered.