Autonomic correlates of attention-deficit/hyperactivity disorder and oppositional defiant disorder in preschool children.

Numerous studies have revealed autonomic underarousal in conduct-disordered adolescents and antisocial adults. It is unknown, however, whether similar autonomic markers are present in at-risk preschoolers. In this study, the authors compared autonomic profiles of 4- to 6-year-old children with attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD; n = 18) with those of age-matched controls (n = 20). Children with ADHD and ODD exhibited fewer electrodermal responses and lengthened cardiac preejection periods at baseline and during reward. Although group differences were not found in baseline respiratory sinus arrhythmia, heart rate changes among ADHD and ODD participants were mediated exclusively by parasympathetic withdrawal, with no independent sympathetic contribution. Heart rate changes among controls were mediated by both autonomic branches. These results suggest that at-risk preschoolers are autonomically similar to older externalizing children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Some effects of single alternation training of rats in a double runway.

Gave independent groups of male hooded rats (n = 30) either (a) single alternation (SA) of reward and nonreward in the 1st goal box of a double runway and 100% reward in the 2nd goal box, (b) concurrent SA in both goal boxes, (c) SA in the 1st goal box and no experience in the 2nd runway, or (d) random 50% reward in the 1st goal box accompanied by 100% reward in the 2nd goal box. SA training in the 1st or in both segments of the double runway yielded reliable SA patterning wherever such training occurred. Concurrent SA training in both segments yielded the fastest development of patterning. "Frustration effects" in the 2nd runway were consistently greater following SA in the 1st goal box than following random reward and nonreward. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modifications of reward expectation-related neuronal activity during learning in primate striatum

This study investigated neuronal activity in the anterior striatum while monkeys repeatedly learned to associate new instruction stimuli with known behavioral reactions and reinforcers. In a delayed go-nogo task with several trial types, an initial picture instructed the animal to execute or withhold a reaching movement and to expect a liquid reward or not. During learning, new instruction pictures were presented, and animals guessed and performed one of the trial types according to a trial-and-error strategy. Learning of a large number of pictures resulted in a learning set in which learning took place in a few trials and correct performance exceeded 80% in the first 60-90 trials. About 200 task-related striatal neurons studied in both familiar and learning conditions showed three forms of changes during learning. Activations related to the preparation and execution of behavioral reactions and the expectation of reward were maintained in many neurons but occurred in inappropriate trial types when behavioral errors were made. The activations became appropriate for individual trial types when the animals' behavior adapted to the new task contingencies. In particular, reward expectation-related activations occurred initially in both rewarded and unrewarded movement trials and became subsequently restricted to rewarded trials. These changes occurred in parallel with the visible adaptation of reward expectations by the animals. The second learning change consisted in decreases of task-related activations that were either restricted to the initial trials of new learning problems or persisted during the subsequent consolidation phase. They probably reflected reductions in the expectation and preparation of upcoming task events, including reward. The third learning change consisted in transient or sustained increases of activations. These might reflect the increased attention accompanying learning and serve to induce synaptic changes underlying the behavioral adaptations. Both decreases and increases often induced changes in the trial selective occurrence of activations. In conclusion, neurons in anterior striatum showed changes related to adaptations or reductions of expectations in new task situations and displayed activations that might serve to induce structural changes during learning.     

Reward, distraction, and the overjustification effect.

A number of experiments have recently demonstrated that extrinsic constraints and rewards can produce lower levels of intrinsic interest in subsequent free-choice situations. This effect has been considered to be the result of a shift in the self-perceived locus of motivation from intrinsic to extrinsic but has also been explained as resulting from the distracting qualities of reward procedures. The latter hypothesis implies that reward and nonreward distractors will produce decreases in intrinsic interest and that these decreases will dissipate over multiple-trial procedures as a result of adaptation. On the other hand, the attribution explanation predicts that rewards or other extrinsic constraints will produce decreases in interest that are stable or strengthened over time. The present experiment, using 132 male and female undergraduates, involved manipulation of 3 levels of the reward/distraction variable (reward, nonreward/distraction, and a nonreward/no-distraction control) crossed with 3 levels of initial trial participation (10, 25, or 50 trials). The results indicate that rewards produced a constant decrease in interest over trials, consistent with the attribution explanation. While there was some evidence for a temporary disruption in intrinsic interest due to nonreward distraction, no support was obtained for a distraction interpretation of the effects of rewards on free-choice behavior. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thought suppression in patients with bipolar disorder.

Suppression of negative thoughts has been observed under experimental conditions among patients with major depressive disorder (MDD) but has never been examined among patients with bipolar disorder (BD). Patients with BD (n = 36), patients with MDD (n = 20), and healthy controls (n = 20) completed a task that required unscrambling 6-word strings into 5-word sentences, leaving out 1 word. The extra word allowed the sentences to be completed in a negative, neutral, or “hyperpositive” (manic/goal-oriented) way. Participants completed the sentences under conditions of cognitive load (rehearsing a 6-digit number), reward (a bell tone), load and reward, or neither load nor reward. We hypothesized that patients with BD would engage in more active suppression of negative and hyperpositive thoughts than would controls, as revealed by their unscrambling more word strings into negative or hyperpositive sentences. Under conditions of load or reward and in the absence of either load or reward, patients with BD unscrambled more negative sentences than did controls. Under conditions of reward, patients with BD unscrambled more negative sentences than did patients with MDD. Patients with BD also reported more use of negative thought suppression than did controls. These group differences in negative biases were no longer significant when current mood states were controlled. Finally, the groups did not differ in the proportion of hyperpositive sentence completions in any condition. Thought suppression may provide a critical locus for psychological interventions in BD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analogical reasoning and the differential outcome effect: Transitory bridging of the conceptual gap for rhesus monkeys (Macaca mulatta).

Monkeys, unlike chimpanzees and humans, have a marked difficulty acquiring relational matching-to-sample (RMTS) tasks that likely reflect the cognitive foundation upon which analogical reasoning rests. In the present study, rhesus monkeys (Macaca mulatta) completed a categorical (identity and nonidentity) RMTS task with differential reward (pellet ratio) and/or punishment (timeout ratio) outcomes for correct and incorrect choices. Monkeys in either differential reward-only or punishment-only conditions performed at chance levels. However, the RMTS performance of monkeys experiencing both differential reward and punishment conditions was significantly better than chance. Subsequently when all animals experienced nondifferential outcomes tests, their RMTS performance levels were at chance. These results indicate that combining differential reward and punishment contingencies provide an effective, albeit transitory, scaffolding for monkeys to judge analogical relations-between-relations. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Reward discounting as a measure of impulsive behavior in a psychiatric outpatient population.

Impulsivity has been operationalized as a choice of an immediate smaller reward over a larger delayed or uncertain reward. This study examined a procedure that measures reward preference under these contingencies in psychiatric outpatients considered either at a high or low risk for engaging in impulsive behavior depending on their psychiatric diagnoses. The participants' rates of delay and uncertainty reward discounting were compared with their performances on a behavioral inhibition task and responses on a self-report personality impulsivity measure. The high-risk participants discounted delayed rewards more sharply and scored higher on the self-report impulsivity measure relative to the low-risk participants. Delay and uncertainty discounting were modestly correlated, but no other relationships were found between the other measures. Results from this study indicate that delay-discounting tasks may be sensitive to at least one form of impulsive behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impairment of probabilistic reward-based learning in schizophrenia.

Recent models assume that some symptoms of schizophrenia originate from defective reward processing mechanisms. Understanding the precise nature of reward-based learning impairments might thus make an important contribution to the understanding of schizophrenia and the development of treatment strategies. The present study investigated several features of probabilistic reward-based stimulus association learning, namely the acquisition of initial contingencies, reversal learning, generalization abilities, and the effects of reward magnitude. Compared to healthy controls, individuals with schizophrenia exhibited attenuated overall performance during acquisition, whereas learning rates across blocks were similar to the rates of controls. On the group level, persons with schizophrenia were, however, unable to learn the reversal of the initial reward contingencies. Exploratory analysis of only the subgroup of individuals with schizophrenia who showed significant learning during acquisition yielded deficits in reversal learning with low reward magnitudes only. There was further evidence of a mild generalization impairment of the persons with schizophrenia in an acquired equivalence task. In summary, although there was evidence of intact basic processing of reward magnitudes, individuals with schizophrenia were impaired at using this feedback for the adaptive guidance of behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Discrimination learning in juvenile delinquents.

Tested 45 delinquent and 45 nondelinquent males in a 2-choice discrimination task with either reward for correct responses, punishment for incorrect responses, or reward and punishment for correct and incorrect responses, respectively. A modified Wisconsin General Test Apparatus was used. Results indicate a significant Group * Reward interaction in which nondelinquent Ss learned best for punishment and delinquent Ss learned best for reward. Results are interpreted as reflecting possible group differences in reward expectancies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impairment of reversal learning in the rat: A mediational explanation.

Examined the finding that reversal learning is impaired when rats are both punished and rewarded for incorrect responses. In Exp. I with 40 male Holtzman rats, it was found that (a) it was necessary for punishment and reward to be administered during both original and reversal learning for such impairment to occur; (b) similar but weaker impairment occurred when nonreward was administered during both original and reversal learning; and (c) reversal learning occurred most rapidly when the consequence of an error (punishment or nonreward) was switched between training and reversal. It is suggested that reversal learning reinstated the emotional state present during original learning and that impairment occurred because the associations formed to that state in training interfered with the behavior required during reversal. Exp. II with 22 Ss confirmed predictions from this hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Preference for unpredictable food rewards occurs with high proportion of reinforced trials or alcohol if rewards are not delayed.

A recently developed mathematical model (DMOD) also predicts that Ss prefer the unpredictable reward situation under conditions that substantially decrease aversiveness of unpredictable nonreward (Daly & Daly, 1982). Because a high proportion of reinforced trials (lenient schedule) and alcohol decrease aversive conditioning, these variables were tested with rats in 5 E-maze experiments. A choice to 1 side of the maze resulted in a stimulus uncorrelated with reward outcome (unpredictable). A choice to the other side resulted in stimuli correlated with reward and nonreward (predictable). Stimuli were not visible until after the choice was made. A lenient reinforcement schedule resulted in preference for the unpredictable reward situation if rewards were not delayed. Alcohol resulted in preference for the unpredictable reward situation if a medium 5-pellet reward was given. A lenient reinforcement schedule combined with an alcohol injection resulted in faster acquisition of the preference for the unpredictable reward situation than did a lenient schedule combined with a saline control injection. These results pose a major challenge to most theories, yet were predicted by DMOD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Achievement-Based Rewards and Intrinsic Motivation: A Test of Cognitive Mediators.

This study assessed how rewards impacted intrinsic motivation when students were rewarded for achievement while learning an activity, for performing at a specific level on a test, or for both. Undergraduate university students engaged in a problem-solving activity. The design was a 2 × 2 factorial with 2 levels of reward in a learning phase (reward for achievement, no reward) and 2 levels of reward in a test phase (reward for achievement, no reward). Intrinsic motivation was measured as time spent on the experimental task and ratings of task interest during a free-choice period. A major finding was that achievement-based rewards during learning or testing increased participants' intrinsic motivation. A path analysis indicated that 2 processes (perceived competence and interest-internal attribution) mediated the positive effects of achievement-based rewards in learning and testing on intrinsic motivation. Findings are discussed in terms of the cognitive evaluation, attribution, and social-cognitive theories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The use of group contingencies for behavioral control: A review.

Two types of group contingencies have been developed to control academic and disruptive behavior in the classroom, in which reinforcement is dependent on (a) a selected individual's or (b) the entire group's performance. Comparisons of group and individual contingencies have generally reported them to be equally effective, with some suggestion that individual Ss characteristics may be of importance. The sociometric status of target S is reportedly affected by group consequences; in 2 experiments, Ss increased in popularity, whereas in 1 report they showed a decline. Other studies have shown an increase in cooperative behavior on an academic task involving group-contingent reward. Absence of or noncontingent reinforcement does not usually produce behavioral control, although a combination of instructions and feedback without extraneous reward has been partially effective. Future research is needed on the interrelation of group contingencies and S characteristics, combinations of group and individual contingencies, and the effects of feedback, instructions, and contingent and noncontingent extraneous reward. (46 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Elimination of vicarious reinforcement effects within an implicit reward situation.

The presence of cognitive evaluations of reward conditions in vicarious reward situations set in typical classrooms has been suggested in theoretical literature. The present study investigated this suggestion by examining the effect of free- versus no-talk conditions between target and peer Ss under vicarious reward conditions. Ss were 18 boys and 14 girls from a typical 4th-grade classroom. Data collected on a task involving reproduction of the letters of the alphabet showed that vicarious reinforcement effects occurred when verbal communication of reward enjoyment to nonreward Ss was possible but not when such communication was restricted. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Skin conductance level reactivity moderates the association between harsh parenting and growth in child externalizing behavior.

Skin conductance level reactivity (SCLR) was examined as a moderator of the association between harsh parenting at age 8 years and growth in child externalizing behavior from age 8 to age 10 (N = 251). Mothers and fathers provided reports of harsh parenting and their children's externalizing behavior; children also provided reports of harsh parenting. SCLR was assessed in response to a socioemotional stress task and a problem-solving challenge task. Latent growth modeling revealed that boys with higher harsh parenting in conjunction with lower SCLR exhibited relatively high and stable levels of externalizing behavior during late childhood. Boys with higher harsh parenting and higher SCLR exhibited relatively low to moderate levels of externalizing behavior at age 8, but some results suggested that their externalizing behavior increased over time, approaching the same levels as boys with higher harsh parenting and lower SCLR by age 10. For the most part, girls and boys with lower harsh parenting were given relatively low and stable ratings of externalizing behavior throughout late childhood. Results are discussed from a developmental psychopathology perspective with reference to models of antisocial behavior in childhood. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Tonic and phasic activation and arousal effects as a function of feedback in repetitive-choice reaction time tasks.

This study examines the effects of positive and negative feedback on performance during choice reaction time tasks to assess whether they differentially affect phasic arousal and tonic activation. Participants (N=96) received either no feedback or signals of reward, punishment, or both during a semantic and a visuospatial repetitive-choice reaction time task. The number of errors made was analyzed both on a trial-by-trial basis and over a continuous series of 80 trials (assessing phasic and tonic feedback effects, respectively). The results show that punishment and reward have different phasic and tonic effects on performance. The data further show that feedback effects interact with the task characteristics: semantic versus visuospatial, and reaction stimulus preceded by a warning signal versus an irrelevant signal. The interaction effects appear to be consistent with the proposed neurological model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reward prediction in primate basal ganglia and frontal cortex

Reward information is processed in a limited number of brain structures, including fronto-basal ganglia systems. Dopamine neurons respond phasically to primary rewards and reward-predicting stimuli depending on reward unpredictability but without discriminating between rewards. These responses reflect 'errors' in the prediction of rewards in correspondence to learning theories and thus may constitute teaching signals for appetitive learning. Neurons in the striatum (caudate, putamen, ventral striatum) code reward predictions in a different manner. They are activated during several seconds when animals expect predicted rewards. During learning, these activations occur initially in rewarded and unrewarded trials and become subsequently restricted to rewarded trials. This occurs in parallel with the adaptation of reward expectations by the animals, as inferred from their behavioral reactions. Neurons in orbitofrontal cortex respond differentially to stimuli predicting different liquid rewards, without coding spatial or visual features. Thus, different structures process reward information processed in different ways. Whereas dopamine neurons emit a reward teaching signal without indicating the specific reward, striatal neurons adapt expectation activity to new reward situations, and orbitofrontal neurons process the specific nature of rewards. These reward signals need to cooperate in order for reward information to be used for learning and maintaining approach behavior.     

Processing of expected and unexpected monetary performance outcomes in healthy older subjects.

The feedback-related negativity (FRN), an event-related potential (ERP) component reflecting feedback processing in the anterior cingulate cortex (ACC), has consistently been found to be reduced in healthy aging, whereas behavioral findings regarding age-related changes in decision making and feedback-based learning are inconsistent. This study aimed to elucidate similarities and differences between healthy younger and older subjects in the processing of monetary performance feedback focusing on effects of reward expectancy. Eighteen younger and 20 older subjects completed a feedback learning task, in which a rule could be learned to predict the reward probabilities associated with particular stimuli. Older subjects showed evidence of slower learning than younger subjects. In both younger and older subjects, the amplitude difference between nonreward and reward in the FRN time window was larger for unexpected than expected outcomes, driven by modulations of negative feedback ERPs. Consistent with previous findings, the amplitude difference tended to be generally reduced in older subjects. P300 amplitude was larger for reward than nonreward in both groups, and interactions between valence and probability indicated that only the P300 for reward was modulated by expectancy. Despite general changes of outcome-related ERPs in healthy aging, older subjects show evidence of preserved effects of expectancy on the processing of monetary feedback. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Child effects on communication between parents of youth with and without attention-deficit/hyperactivity disorder.

Numerous studies indicate interparental conflict causes child externalizing behavior. However, far less is known about the inverse relationship. Exploring this gap in the literature has clear implications for parents of children with externalizing disorders (e.g., attention-deficit/hyperactivity disorder [ADHD]). Adapting an experimental child behavior manipulation paradigm (Lang, Pelham, Atkeson, & Murphy, 1999; Pelham et al., 1997, 1998), parent couples of 9- to 12-year-old boys and girls with ADHD (n = 51) and without ADHD (n = 39) were randomly assigned to interact with a “disruptive” or “typical” confederate child. According to parent and observer ratings, parents interacting with disruptive confederates communicated less positively and more negatively with each other during and after the interactions than did parents who interacted with typical confederates. Observational coding also indicated that child effects on negative interparental communication were more noticeable among parents of youth with ADHD, particularly those with comorbid oppositional defiant disorder or conduct disorder, compared with parents of youth without ADHD. These findings extend results of prospective studies highlighting child effects on marital quality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)