Reward value effects on timing in the peak procedure

Three experiments examined the effect of motivational variables on timing in the peak procedure. In Experiment 1, rats received a 60-s peak procedure that was coupled with long-term, between-phase changes in reinforcer magnitude. Increases in reinforcer magnitude produced a leftward shift in the peak that persisted for 20 sessions of training. In a final phase, the rats received lithium chloride-induced aversion prior to testing and a rightward shift in the peak was observed. Experiment 2 confirmed the rightward shift in the peak under lithium chloride devaluation and induced a comparable shift with satiety devaluation. The degree of rightward shift was neither additive nor multiplicative, suggesting that two processes may have contributed. Experiment 3 examined the effect of extinction on peak responding, revealing a decrease in response rate, but no evidence of any change in the timing of responding. The implications of the results for contemporary timing theories are discussed.     

Reward sensitivity in depression: a biobehavioral study

The approach-withdrawal model posits 2 neural systems of motivation and emotion and hypothesizes that these systems are responsible for individual differences in emotional reactivity, or affective styles. The model also proposes that depression is characterized by a deficit in reward-seeking behavior (i.e., approach motivation) and is associated with a relative decrease in left frontal brain activity. The authors tested aspects of this model by comparing the electroencephalogram alpha power of depressed and nondepressed individuals during a task that manipulated approach motivation. The study found that control participants and individuals with late-onset depression exhibited the hypothesized increase in left frontal activity during the approach task but individuals with early-onset depression did not. This suggests that early-onset depression may be associated with a deficit in the hypothesized approach motivation system.     

The organization of non-nutritive sucking in the premature infant

Changes in non-nutritive sucking contingent upon the repeated presentation of unpatterned and patterned light stimulation were examined in a sample of 18 premature infants. Stimulus contingent sucking change in chronologically younger infants tended to be somewhat shorter in duration than that of the chronologically older infants and showed stimulus contingent sucking acceleration as well as suppression. Evidence was also found for less orienting among infants showing abnormalities in their sucking behavior. No evidence for habituation was found in any subgroup. Possible factors contributing to the strength and nature of stimulus contingent non-nutritive sucking changes in infants are discussed.     

Reward, punishment, and cooperation: a meta-analysis

How effective are rewards (for cooperation) and punishment (for noncooperation) as tools to promote cooperation in social dilemmas or situations when immediate self-interest and longer term collective interest conflict? What variables can promote the impact of these incentives? Although such questions have been examined, social and behavioral scientists provide different answers. To date, there is no theoretical and/or quantitative review of rewards and punishments as incentives for cooperation in social dilemmas. Using a novel interdependence-theoretic framework, we propose that rewards and punishments should both promote cooperation, and we identify 2 variables—cost of incentives and source of incentives—that are predicted to magnify the effectiveness of these incentives in promoting cooperation.A meta-analysis involving 187 effect sizes revealed that rewards and punishments exhibited a statistically equivalent positive effect on cooperation (d =0.51 and 0.70, respectively). The effectiveness of incentives was stronger when the incentives were costly to administer, compared to free. Centralization of incentives did not moderate the effect size. Punishments were also more effective during iterated dilemmas when participants continued to interact in the same group, compared to both (a) iterated dilemmas with reassignment to a new group after each trial and (b) one-shot dilemmas. We also examine several other potential moderators, such as iterations, partner matching, group size, country, and participant payment. We discuss broad conclusions, consider implications for theory, and suggest directions for future research on rewards and punishment in social dilemmas.     

Reward priming of temporal preparation

Recent studies have demonstrated a strong impact of reward on the expectancy of future target locations or features. In this study, we examined whether reward would have similar effects on temporal preparation. In two experiments, participants completed a reaction time task with a variable interval between a warning stimulus and the target stimulus. After each trial they were awarded either low or high reward which was converted to cash after the experiment. Crucially, reward magnitude was assigned randomly and was unrelated to task performance. Nevertheless, across experiments, the results revealed that reward modified future temporal preparation, especially in participants that could be identified as highly motivated. These findings generalize the principles of reward priming to the temporal domain.     

Reward boosts working memory encoding over a brief temporal window

Selection mechanisms for WM are ordinarily studied by explicitly cueing a subset of memory items. However, we might also expect the reward associations of stimuli we encounter to modulate their probability of being represented in working memory (WM). Theoretical and computational models explicitly predict that reward value should determine which items will be gated into WM. For example, a model by Braver and colleagues in which phasic dopamine signalling gates WM updating predicts a temporally-specific but not item-specific reward-driven boost to encoding. In contrast, Hazy and colleagues invoke reinforcement learning in cortico-striatal loops and predict an item-wise reward-driven encoding bias. Furthermore, a body of prior work has demonstrated that reward-associated items can capture attention, and it has been shown that attentional capture biases WM encoding. We directly investigated the relationship between reward history and WM encoding. In our first experiment, we found an encoding benefit associated with reward-associated items, but the benefit generalized to all items in the memory array. In a second experiment this effect was shown to be highly temporally specific. We speculate that in real-world contexts in which the environment is sampled sequentially with saccades/shifts in attention, this mechanism could effectively mediate an item-wise encoding bias, because encoding boosts would occur when rewarded items were fixated.     

Effects of auditory stimulation upon non-nutritive sucking by premature infants.

Changes in non-nutritive sucking contingent upon presentation of an auditory stimulus previously found capable of eliciting heart-rate acceleration was investigated in a sample of 24 premature infants. Across 30 10-sec. presentations of the stimulus, only transient changes in sucking rate during the first 6 trials were observed, and these effects obtained primarily for those infants showing few abnormalities in their non-nutritive sucking behavior. These results were discussed as reflecting possible differences in infants' attention associated with sucking pathology and the dependence of psychological assessment upon the specific response index used.     

Strength of a Secondary Reinforcement as a Function of the Quality of Food Reward

Thirty-two children were presented 18 stories containing either a good, neutral, or negative act which was followed by either a reward or punishment. It was predicted that Ss' responses would be influenced by the sanctions. It was also predicted that the type of story (good, neutral, or bad) would influence the extent to which a child judged the act independent of the effects of the sanction (reward or punishment).

These predictions were supported. Ss made more positive responses to acts followed by reward than to those followed by punishment. However, an examination of a Content × Sanction interaction found the sanction of reward relatively ineffective for the stones with negative content.     

Reward modulates adaptations to conflict

Both cognitive conflict (e.g. Verguts & Notebaert, 2009) and reward signals (e.g. Waszak & Pholulamdeth, 2009) have been proposed to enhance task-relevant associations. Bringing these two notions together, we predicted that reward modulates conflict-based sequential adaptations in cognitive control. This was tested combining either a single flanker task (Experiment 1) or a task-switch paradigm (Experiment 2) with performance-related rewards. Both experiments confirmed that adaptations after conflict were modulated by reward. In the flanker task, this resulted in increased conflict adaptation after rewarded trials. In the task-switching experiment, reward increased the conflict-modulated switch cost. Interestingly, both adaptations to conflict disappeared after no-reward trials. Moreover, individual differences in participants' sensitivity to reward predicted these reward modulations of trial-to-trial adaptations. These findings shed new light on the exact role of cognitive conflict in shaping subsequent behavior.     

Operant Reward Learning in Aplysia

Anticipating the future has a decided evolutionary advantage, and researchers have found many evolutionarily conserved mechanisms by which humans and animals learn to predict future events. Researchers often study such learned behavior using conditioning experiments. The marine snail Aplysia has been at the forefront of research into the cellular and molecular mechanisms of classical conditioning. Recently, Aplysia has also gained a reputation as a valuable model system for operant reward learning. Its feeding behavior can be operantly conditioned in the intact animal as well as in reduced preparations of the nervous system. The reward signal relies on dopamine transmission and acts in conjunction with activity in an identified neuron (B51) to bring about operant memory.     

Examining Individual Differences in Social Reward Valuation: a Person-Based Approach

Social reward refers to the motivational and pleasurable aspects of our interactions with other people. While some people experience social encounters as pleasurable, others experience them as aversive. However, the current knowledge on individual differences in social reward valuation in relation to pro- and antisocial personality characteristics is limited. The Social Reward Questionnaire (SRQ) was developed to assess individual differences in the value of different types of social rewards. First, the present study examined the validity and reliability of the Dutch version of the SRQ in a Dutch and Flemish community sample (N?=?1892). Second, using latent profile analysis (LPA), it was investigated whether subgroups of participants existed with distinctive patterns of social reward valuation, and whether these subgroups differed in their level of psychopathic traits, aggression, and social anxiety. The results confirmed the original six-factor structure and showed good reliability and validity. The LPA identified four classes of individuals, labelled as: Low Social Interest, High Social Interest, Undifferentiated Social Reward-seekers, and Socially Cruel. These classes were further typified by distinct levels of psychopathy, reactive and proactive aggression, and social anxiety. The present findings contribute to our understanding of individual variability in the underlying motives of social behaviors.

     

Erratum to: Sensory Nature of Reward

Integrative Psychological and Behavioral Science -     

Effect of Reward Contingency on Intrinsic Motivation

The effects of type of task and type of reward contingency on intrinsic motivation for subsequent task performance were investigated. The sample consisted of 50 young Indian adults. The results showed a significantly greater amount of free choice time spent on a heuristic task rather than an algorithmic task. The verbal measures of intrinsic motivation yielded a significant effect of reward contingency with greater intrinsic motivation under performance-contingent reward, followed by task-contingent and no-reward conditions, respectively. The results support self-determination and competence processes as important mediators of intrinsic motivation.