Elevated levels of impulsivity and reduced place conditioning with d-amphetamine: Two behavioral features of adolescence in mice.

Human adolescents may have experience with easily available psychoactive drugs. Impulsivity and/or peculiarities in reward systems may play a role. These variables were studied in adolescent (Postnatal Day [PND] 30-49) and adult (PND > 60) CD-1 mice. In Experiment 1 (impulsivity), food-restricted mice were tested in operant chambers with 2 nose-poking holes that delivered 1 food pellet immediately or 5 pellets after a delay, respectively. Delay length was increased over days (0-100 sec). Adolescent mice showed a shift to the left in the intolerance-delay curve, as well as enhanced demanding when nose-poking was not reinforced. In Experiment 2 (place conditioning with d-amphetamine at 0.0, 1.0, 2.0, 3.3, or 5.0 mg/kg for 3 days), adolescent mice showed no reliable evidence of place conditioning when compared with adults. Hence, 2 main features of adolescence were elevated impulsivity and restlessness, and low (or absent) rewarding efficacy of amphetamine. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impulsivity and rapid discounting of delayed hypothetical rewards in cocaine-dependent individuals.

In this study, crack/cocaine-dependent (CD) and non-drug-using matched control (MC) participants were presented with hypothetical immediate and delayed rewards, with 16 delay conditions ranging from 5 min to 25 years. All participants were presented with hypothetical monetary rewards; however, the CD group was also presented with hypothetical crack/ cocaine rewards. The objective value of the rewards ranged from $1 to $1,000. Hyperbolic discounting functions provided a good fit of the data. The CD group discounted monetary rewards at a higher rate than the MC group did, and the CD group discounted crack/cocaine rewards at a higher rate than it did monetary rewards. Moreover, scores on self-report measures indicated greater impulsivity in the CD group when compared with the MC group. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tailoring dialysis and resuming low‐protein diets may favor chronic dialysis discontinuation: Report on three cases

Renal function recovery (RFR), defined as the discontinuation of dialysis after 3 months of replacement therapy, is reported in about 1% of chronic dialysis patients. The role of personalized, intensive dialysis schedules and of resuming low‐protein diets has not been studied to date. This report describes three patients with RFR who were recently treated at a new dialysis unit set up to offer intensive hemodialysis. All three patients were females, aged 73, 75, and 78 years. Kidney disease included vascular‐cholesterol emboli, diabetic nephropathy and vascular and dysmetabolic disease. At time of RFR, the patients had been dialysis‐dependent from 3 months to 1 year. Dialysis was started with different schedules and was progressively discontinued with a “decremental” policy, progressively decreasing number and duration of the sessions. A moderately restricted low‐protein diet (proteins 0.6 g/kg/day) was started immediately after dialysis discontinuation. The most recent update showed that two patients are well off dialysis for 5 and 6 months; the diabetic patient died (sudden death) 3 months after dialysis discontinuation. Within the limits of small numbers, our case series may suggest a role for personalized dialysis treatments and for including low‐protein diets in the therapy, in enhancing long‐term RFR in elderly dialysis patients.     

Temporal Discounting When the Choice Is Between Two Delayed Rewards.

The present experiments extend the temporal discounting paradigm from choice between an immediate and a delayed reward to choice between 2 delayed rewards: a smaller amount of money available sooner and a larger amount available later. Across different amounts and delays, the data were consistently well described by a hyperbola-like discounting function, and the degree of discounting decreased systematically as the delay to the sooner reward increased. Three theoretical models (the elimination-by-aspects, present-value comparison, and common-aspect attenuation hypotheses) were evaluated. The best account of the data was provided by the common-aspect attenuation hypothesis, according to which the common aspect of the choice alternatives (i.e., the time until the sooner reward is available) receives less weight in the decision-making process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The double-edged sword of rewards for participation in psychology experiments.

This quasi-experimental study examined participation rates and sample characteristics of participants recruited with and without the offer of course credit. In Sample 1, where course credit is not usually offered, credit was added in one condition (N = 195) and not in the other (N = 175). In Sample 2, where credit is usually offered, it was maintained in one condition (N = 92) and removed in the other (N = 178). Results in both samples revealed that participation rates were higher in the credit conditions; they plunged when customary rewards were taken away. Results also revealed evidence of sample bias. More specifically, the motivational characteristics of participants and nonparticipants differed in all conditions except the new credit condition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Concave utility, transaction costs, and risk in measuring discounting of delayed rewards.

Research has consistently found that the decline in the present values of delayed rewards as delay increases is better fit by hyperbolic than by exponential delay-discounting functions. However, concave utility, transaction costs, and risk each could produce hyperbolic-looking data, even when the underlying discounting function is exponential. In Experiments 1 (N=45) and 2 (N=103), participants placed bids indicating their present values of real future monetary rewards in computer-based 2nd-price auctions. Both experiments suggest that utility is not sufficiently concave to account for the superior fit of hyperbolic functions. Experiment 2 provided no evidence that the effects of transaction costs and risk are large enough to account for the superior fit of hyperbolic functions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Underlying sources of job satisfaction.

Recent theories of job satisfaction generally assume 2 underlying types of job elements important to employee satisfaction: those in the work process which allow for self-actualization, and environmental elements in which the worker's rewards are physical and monetary. A parallel assumption pertains to the 2 types of employees for whom each of these is important. A validation of such constructs was attempted through factor analysis and indicated 3 underlying groups of job elements important to job satisfaction: social and technical environment, intrinsic work aspects, and recognition through advancement. The factor of greatest import to each employee was identified, and factored groups of employees were described in terms of their differing age, salary, and occupational patterns. No significant differences in overall job satisfaction among the 3 groups were found. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychopathy and punishment.

An experiment to test the hypothesis that psychopathy is associated with deficient passive avoidance learning under punishment. 75 High Pd and 75 Low Pd female undergraduates, equated for intelligence, learned a list of 10 nonsense syllables under 1 of 3 conditions of reinforcement: verbal reward, verbal punishment, and absence of comment by E. Punishment significantly retarded the learning of Low Pd Ss, but not that of High Pd Ss. No significant differences occurred under reward or neutral conditions. The hypothesis was considered confirmed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The motivational bases of attitude change.

In describing the motivational forces which determine attitude formation and change, the authors focus upon three basic variables: reward and punishment, reality testing, and ego defensiveness. Methodological approaches which seem to lead to appropriate tests of hypotheses generated by the discussion are presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Delay of gratification, motivation for the prohibited gratification, and responses to temptation.

Yielding to temptation, in a situation in which attainment of achievement rewards is contingent upon deviant (cheating) behavior, was conceptualized to be a function of (a) the strength of the motivation to attain the prohibited gratification, and (b) the inability to delay immediate gratification. 6th-grade boys participated in an experimentally controlled "shooting gallery" game of skill in which attainment of achievement rewards (prizes) was contingent upon the child's falsifying his own scores. Motivation for the prohibited gratification was inferred from "n Achievement" scores: preference for immediate, smaller (ImR) or delayed, larger (DelR) rewards in choice situations was the index of the ability to delay gratification. Achievement motivation was related to the S's producing sufficiently deviant scores to obtain an achievement reward, and preference for DelR was related negatively to the amount of cheating and positively to the latency of cheating, i.e., the number of trials before the occurrence of the 1st deviation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)