The distracting effect of material reward: An alternative explanation for the superior performance of reward groups in probability learning

To determine whether the distraction effect associated with material rewards in discrimination learning can account for the superior performance of reward groups in probability learning, the performance of 144 school children (preschool, second, and fifth grades) on a two-choice successive discrimination task was compared under three reinforcement conditions (material reward, marker, and knowledge of results). The two events in the task had different frequencies of occurrence, as in probability learning, yet they appeared in a constant order to make 100% payoff possible. The subjects in the reward and marker groups learned the task more slowly, and the nonlearners among them used stereotyped alternation patterns to a greater degree than subjects in the knowledge-of-results condition. These findings suggest that a distracting effect of material reward is present in probability learning and may explain the superior performance of reward groups typically found in probability learning studies.     

Anticipation of reward omission as a cue for choice behavior

A within-subject partial reinforcement extinction effect was obtained in a conditional discriminative choice task. In choice acquisition, one group had learned a task in which one choice alternative was continuously reinforced (CRF) and the other alternative was partially reinforced (PRF). Most errors in the acquisition phase were the choosing of the CRF lever when the conditional stimulus signaled the PRF lever; in extinction this pattern of choice errors reversed. In extinction, most errors were choosing of the PRF lever when the conditional stimulus signaled the CRF lever. The predictions of frustration theory and sequential theory were compared with the choice data. The results were interpreted as consistent with the anticipatory frustration construct within an associative mediational theory.     

Effects of reward distribution and performance feedback on competitive responding

To implement competitive contingencies, one must select a distribution of unequal rewards and a schedule of feedback for competitors regarding one another's performance. This study investigated three bases for distributing rewards and two performance feedback conditions. Pairs of college students competed over a series of 2-min contests in which the competitive response was a knob pull. A sum of money was divided using a proportional distribution or one of two fixed reward distributions. In the proportional distribution, a subject's proportion of the sum was his or her proportion of the total number of responses. The two fixed distributions were divisions of 100%/0% or 67%/33%. Also, in every contest either subject could make a response that would end the contest prematurely and give both subjects the same amount—a sum equal to 33% of the competitive total. In the two feedback conditions, cumulative responses by each subject were either shown to both subjects during the contest or were not shown. The proportional distribution was clearly superior to either of the fixed distributions in number of responses produced across contests. The proportional distribution with feedback produced the largest number of competitive responses, and the 100%/0% distribution without feedback produced the smallest number. Differences among distributions typically emerged only during later blocks of contests. Fixed distributions of rewards often produced decelerating rates of responding, with losing competitors ending the contests before they were completed. Response-rate decreases were greatest for pairs in which the 2 subjects differed most in their response rates and proportion of wins. The presence of feedback had a small effect, increasing responding for some pairs in the 100%/0% distribution. Performance patterns were interpreted in terms of the consequences arranged for the individual participants by the reward distributions and differences in performance between competitors.     

An assessment of factors contributing to instrumental performance for sexual reward in the rat

Male and female rats were gonadectomized, implanted in adulthood with capsules containing either testosterone propionate (TP) or cholesterol, and were trained to lever press for access to an oestrous female. When lever press performance was tested in extinction, only the male rats implanted with TP displayed significantly higher levels of responding than controls, demonstrating that lever pressing for oestrous females as a reward is sexually dimorphic. Ejaculation patterns from a separate assessment of these rats' copulatory ability were significantly correlated with their instrumental performance. In a second experiment, "masculinized" females exposed to TP postnatally and given TP implants responded in extinction at mean levels equivalent to those exhibited by adult males that were either intact or castrated with androgen replacement. These data suggest that organizational steroid exposure perinatally affects the actual reward value assigned to oestrous females inadulthood, in combination withconsummatory sexual experience.     

Deprivation and reward stimuli as compound stimuli

In Experiment 1 the experimental group was tested with a deprivation level and a reward magnitude which it had experienced previously but which it had not experienced in combination. This group was inferior in test performance to a group which had experienced the test deprivation-reward combination prior to test. These results were interpreted as indicating that deprivation stimuli and reward stimuli form a compound stimulus and training on the elements of the compound produces performance inferior to training directly on the compound. In Experiment 2, the decrement associated with two different shifts in deprivation and reward did not differ despite the different size change of total incentive involved in the two shifts. The results were interpreted as indicating that the deprivation-reward stimulus is not produced by a single underlying incentive mechanism.     

A new perspective on human reward research: How consciously and unconsciously perceived reward information influences performance

The question of how human performance can be improved through rewards is a recurrent topic of interest in psychology and neuroscience. Traditional, cognitive approaches to this topic have focused solely on consciously communicated rewards. Recently, a largely neuroscience-inspired perspective has emerged to examine the potential role of conscious awareness of reward information in effective reward pursuit. The present article reviews research employing a newly developed monetary-reward-priming paradigm that allows for a systematic investigation of this perspective. We analyze this research to identify similarities and differences in how consciously and unconsciously perceived rewards impact three distinct aspects relevant to performance: decision making, task preparation, and task execution. We further discuss whether conscious awareness, in modulating the effects of reward information, plays a role similar to its role in modulating the effects of other affective information. Implications of these insights for understanding the role of consciousness in modulating goal-directed behavior more generally are discussed.     

Effect of shifts in body weight on rats' straight alley performance as a function of reward magnitude

The performance of rats trained in a straight alley for 55 trials under 75% body weight and then shifted to 90% body weight was compared to that of rats trained only under 90% body weight. When training was with a small reward the speed of the shifted group decreased to the level of the 90% small reward control groups, but when training was with a large reward the speed of the shifted group dropped below the level of the 90% large reward control group. Thus, the effects on performance of shifting deprivation level following extended training depend on the reward magnitude employed.     

Effects of list length and first-trial reward upon concurrent discrimination performance

Rhesus monkeys were given 2304 two-trial object discrimination problems that were presented as members of lists consisting of two, four, or eight problems. The problems within each list were presented concurrently, Trial 1 for all problems in the list being presented before initiation of Trial 2 for any problem. Each problem involved exposure of a single object on Trial 1, which was either rewarded or not rewarded, followed by presentation of the Trial 1 object along with a second object on Trial 2. Performance varied inversely with list length, and this effect became more prominent as a function of training. Performance after Trial 1 nonreward was substantially better than that after Trial 1 reward, and this effect became enhanced both with continued training and with increased list length. The findings were discussed in terms of Bessemer's short-term memory analysis of learning set.