Transfer between downshift in reward magnitude and continuous delay of reward

Two separate experiments were conducted to investigate transfer of persistence between delay and a downshift in reward magnitude. In the first experiment, experimental rats were initially downshifted in reward magnitude and later tested for persistence to continuous delay of large reward. It was found that these rats were more persistent to the effects of delay than control rats which did not receive prior experience with a downshift in reward magnitude. In the second experiment, experimental rats were first trained to receive large reward under delayed conditions and then tested for persistence to a downshift in reward magnitude. Compared to control rats which received no prior experience with delay, the experimental rats showed a significantly smaller negative contrast effect. The results were interpreted as supporting Amsel's theory of persistence as well as Capaldi's recent interpretation of contrast effects.     

Self-stimulating rats combine subjective reward magnitude and subjective reward rate multiplicatively

For rats that bar pressed for intracranial electrical stimulation in a 2-lever matching paradigm with concurrent variable interval schedules of reward, the authors found that the time allocation ratio is based on a multiplicative combination of the ratio of subjective reward magnitudes and the ratio of the rates of reward. Multiplicative combining was observed in a range covering approximately 2 orders of magnitude in the ratio of the rates of reward from about 1:10 to 10:1) and an order of magnitude change in the size of rewards. After determining the relation between the pulse frequency of stimulation and subjective reward magnitude, the authors were able to predict from knowledge of the subjective magnitudes of the rewards and the obtained relative rates of reward the subject's time allocation ratio over a range in which it varied by more than 3 orders of magnitude.     

On being imitated: Effects on reward and reward value of the imitator

The effects of being imitated on the model's reward of imitating and nonimitating confederates and on the confederates' reward value were assessed. Forty-eight first graders served as subjects. It was found that more children showed a bias in giving reward to the imitating confederate than to the nonimitating confederate. This effect was particularly strong for children classified as having an internal locus of control. Second, no difference in confederates' reward value was obtained as measured by operantly conditioned responding on a marble-drop task.     

The reward value of peers

Sixteen socially isolate preschoolers were classified as peer- or non-peer-oriented on the basis of their responses to a test devised to measure the reward value of peers. Half of the subjects in each classification were assigned to a modeling treatment and viewed a film depicting appropriate social behavior in the nursery school; half served as controls and saw an animal film. Peer-oriented modeling film subjects increased significantly more in their peer social interactions at posttest and follow-up assessments than did the non-peer-oriented modeling group. In addition, both peer-oriented and non-peer-oriented modeling groups were significantly higher on peer interaction than the control groups. Alternative and supplemental procedures for increasing isolate preschoolers' social interaction are discussed.     

The inherent reward of choice

Research suggests that the exercise of control is desirable and adaptive, but the precise mechanisms underlying the affective value of control are not well understood. The study reported here characterized the affective experience of personal control by examining the neural substrates recruited when individuals anticipate the opportunity to make a choice--in other words, when they anticipate the means for exercising control. We used an experimental paradigm that probed the value of having a choice. Participants reported liking cues that predicted a future opportunity to make a choice more than cues that predicted no choice. The anticipation of choice itself was associated with increased activity in corticostriatal regions, particularly the ventral striatum, involved in affective and motivational processes. This study is the first direct examination of the affective value of having the opportunity to choose. These findings have important implications for understanding the role of perception of control, and choice itself, in self-regulatory processes.     

Partial reward training level and reward magnitude: Effects on acquisition and extinction

Two groups of 10 rats each received either a large magnitude (0.90 g) or a small magnitude (0.18 g) of partial reward (PR) and seven successive acquisition-extinction sessions in the runway. The large magnitude PR group ran much faster than the small magnitude PR group in the early acquisition sessions with differences between the groups declining over sessions. In the early extinction sessions, the large magnitude PR group showed greater resistance to extinction than the small magnitude PR group, but in the late extinction sessions this relation reversed itself. Finally, resistance to extinction decreased over sessions, this decrease being greater under a large than under a small magnitude of PR.     

Order of partial and consistent reward,reward magnitude shift,and resistance to extinction

In a separate-phase runway experiment with rats, four schedules involving partial (P) and consistent (C) reward (CC, CP, PC, and PP) were crossed with three reward magnitude shift conditions (upshift, nonshift, and downshift). The data revealed three major findings: (a) Reward magnitude downshift generally led to rapid extinction; (b) consistent reward prior to partial reward (CP) resulted in slower extinction than the reverse order (PC) under conditions of reward magnitude shift (particularly downshift); and (c) the relative performance of PC and CP under conditions of reward magnitude shift was reversed from postshift to extinction. On the basis of these data it was suggested that processes not presently identified by reinforcement level theory and stimulus analyzer theory influence extinction following separate-phase acquisition. A modification of reward level theory was presented to provide an account of extinction performance following separate-phase reward reduction.     

Evaluation of a fortuitously reward other

Under the guise of an experiment on gambling decisions, subjects briefly met a confederate of the experimenter, whom they later evaluated. The major hypothesis was that the confederate would be evaluated more favorably by subjects who were told that she had received a fortuitous reward than by control subjects. The hypothesis was confirmed for female subjects only.     

The reward value of near-miss situations

Svartdal, F. (2011). The reward value of near‐miss situations. Scandinavian Journal of Psychology52, 209–217. What is a “positive” outcome? Clearly, obtaining something attractive is regarded as positive, but so is avoiding something negative. The present paper compared these two types of situations in scenario‐type evaluations. Participants rated positive (P), avoiding negative (AN), and negative (N) outcomes in terms of luck (Experiment 1) and overall positive/negative evaluations (Experiments 2 and 3). The results demonstrated that evaluations of P and AN outcomes were judged as equally positive, but the emotional basis for these evaluations was very different: The feeling of relief was the dominating emotion in AN situations, whereas joy was the dominating emotion in P situations. Overall, these results indicate that avoidance‐induced reward value may be important as a motivating factor in cognition and action.     

Control of variation by reward probability

Two bar-press experiments with rats tested the rule that reducing expectation of reward increases the variation from which reward selects. Experiment 1 used a discrete-trial random-interval schedule, with trials signaled by light or sound. One signal always ended with reward; the other signal ended with reward less often. The 2 signals were randomly mixed. Bar-press duration (how long the bar was held down) varied more during the signal with the lower probability of reward. Experiment 2 closely resembled Experiment 1 but used a random-ratio schedule rather than a random-interval schedule. Again, bar-press duration varied more during the signal with the lower probability of reward. The results support the rule--the first well-controlled comparisons to do so.