Effect of failure/success feedback and the moderating influence of personality on reward motivation

While motivation to pursue goals is often assumed to be a trait-like characteristic, it is influenced by a variety of situational factors. In particular, recent experiences of success or failure, as well as cognitive responses to these outcomes, may shape subsequent willingness to expend effort for future rewards. To date, however, these effects have not been explicitly tested. In the present study, 131 healthy individuals received either failure or success feedback on a cognitive task. They were then instructed to either ruminate or distract themselves from their emotions. Finally, they completed the Effort Expenditure for Rewards Task, a laboratory measure of reward motivation. Results indicate that participants who received failure feedback relied more strongly on the reward magnitude when choosing whether to exert greater effort to obtain larger rewards, though this effect only held under conditions of significant uncertainty about whether the effort would be rewarded. Further, participants with high levels of trait inhibition were less responsive to reward value and probability when choosing whether to expend greater effort, results that echo past studies of effort-based decision-making in psychological disorders.     

Stress and emotional valence effects on children's versus adolescents’ true and false memory

Despite considerable interest in understanding how stress influences memory accuracy and errors, particularly in children, methodological limitations have made it difficult to examine the effects of stress independent of the effects of the emotional valence of to-be-remembered information in developmental populations. In this study, we manipulated stress levels in 7–8- and 12–14-year-olds and then exposed them to negative, neutral, and positive word lists. Shortly afterward, we tested their recognition memory for the words and false memory for non-presented but related words. Adolescents in the high-stress condition were more accurate than those in the low-stress condition, while children's accuracy did not differ across stress conditions. Also, among adolescents, accuracy and errors were higher for the negative than positive words, while in children, word valence was unrelated to accuracy. Finally, increases in children's and adolescents’ cortisol responses, especially in the high-stress condition, were related to greater accuracy but not false memories and only for positive emotional words. Findings suggest that stress at encoding, as well as the emotional content of to-be-remembered information, may influence memory in different ways across development, highlighting the need for greater complexity in existing models of true and false memory formation.     

Adjunctive brainstem behaviors in the rat

Adjunctive behaviors refers to behaviors that are “out of context” and/or excessive in amount. The terminology was first used for unexplained behaviors associated with food pellet ratio contingencies in food deprived rats (Falk, 1971). Clinically, unrelated and complex excessive behaviors were also noted with brainstem and diencephalic discharges (Andy, 1986, 1989 and 1995; Andy and Jurko, 1986). The objective of this study was to develop a model of brainstem generated adjunctive behaviors in the rat. Method: Sixty-one adult rats were used. Kindling was induced by mechanical and DC electrical perturbations in the midbrain. Nine different treatment groups were established in which lesions and drugs were used separately and in different combinations. Cocaine was used to accentuate, and dextrorphan to attenuate the kindling process. Behaviors were visually analyzed and recorded by video camera; they were not quantified. DC stimulation and EEGs were done with Grass instruments. Recording and stimulation sights were verified histologically. Results: A total of 45 different behaviors were elicited. DC stimulation kindled subjects had significantly more behaviors than did electrode insertion alone and cocaine alone. However, cocaine combined with DC stimulation increased the number and intensity of the kindled behaviors. Dextrorphan tended to facilitate catatonic and sleep states. Behaviors occurred randomly and were unrelated, even when they occurred in clusters. The behaviors were associated with four abnormal EEG discharge patterns. Conclusion: We speculate that brainstem behaviors are innate adjunctive drives that are generated in the brainstem reticular formation. They are monitored by the cortex and partially modified by environmental and cortical inputs.     

Are twins different from singletons during early childhood?

This paper examines the specificity of intrafamilial experiences to which twins are exposed during early childhood, and the impact of this family context on the psychological development of twins. An overview of the literature on the psychological development of twins indicates two broad categories of findings. The first category covers studies dealing with the developmental features that appear early in twins. Although there are numerous studies comparing the psychomotor and verbal development of twins to singletons, only a few have dealt with the emergence of personality and identity, and most have been conducted in clinical settings. The second set of studies deals with mother-twin relations, explored in recent years in terms of the psychosocial stress created by twin births. Few studies have examined the mother-twin relationship in the light of major theories on mother-child bonding (psychoanalysis, attachment, interactionist model). These developmental models have mainly focused on mother-infant dyads, while the construction of this specific mother-twin relationship needs to be set within the framework of a triadic situation. Rather than describing a specific ‘twin mentality’, it is argued here that the twin situation should be seen as a special case of adaptative development, both for the mother and the child, which has effects on the formation of the individual.     

Cognitive processing of uncertainty: Its effect on pupillary dilation and preference ratings

The prediction of greater pupillary dilation as unpredictability (induced by random-turn shapes) increased was supported (p <.001) in studies involving 40 young adults and 10 children. The postulated linearity of this increase found support, except in cases where apparent stimulus-selection strategies attenuated the dilation at higher levels of variability. Those Ss who did preference ratings concomitantly with the intake of visual unpredictability evidenced significantly greater dilation (p <.001) at the time of reporting the rating. Both children and adults dilated significantly less to the shapes after prolonged experience with similar stimuli. indicating development of either ability to handle variability or to selectively filter input, but age was not a factor. The lack of any significant relationship between pupillary dilation and preference indicated the need for more definitive work in determining when these two indices profitably complement each other. Finally, adults dilated more to provocative auditory stimuli than to the visual shapes.     

Mood-induction research—its implications for clinical depression

Mood-induction procedures (MIPs) are increasingly being used as laboratory analogues of clinical depression. Four methods of mood induction are described: reading depressing self-referent statements: remembering past unpleasant events; listening to a taped depressing story: and failure on a task. The effects of these MIPs on affect, behaviour and related variables and parallels between these effects and clinical deficits are reviewed. The implications of MIP research for clinical depression are discussed in the light of self-awareness theory, mood effects on memory, and the inter-relationship between cognitive and somatic variables in depression.     

Depression,restraint and eating behavior

Contrary to the belief that weight loss is a principal symptom of depression, several recent studies have suggested that certain people gain rather than lose weight when depressed. The present experiment concerned the effects of experimentally induced mood states on the eating behavior of high- and low-restraint persons. Sixty-eight female undergraduates were randomly assigned to one of three groups each designed to induce a different mood state (depressed, neutral or elated), and were classified as high or low restraint based on their responses to a questionnaire. During the mood induction procedure subjects were provided with the opportunity to eat. High-restraint persons induced into a depressed mood ate significantly more than high-restraint persons induced into neutral or elated moods, and more than low-restraint persons induced into a depressed mood. This effect was most prominent among subjects who scored high on the weight-fluctuation factor of the restraint scale. There was no evidence that this effect occurred among subjects who scored high on the concern for dieting factor. The role of emotional arousal on the self-control over eating behavior of high weight-fluctuation persons, and the implications of these findings for the evaluation of depression were discussed.     

The opponent-process theory of motivation: VIII. Quantitative and qualitative manipulations of food both modulate adjunctive behavior

The present studies extend the opponent-process theory of acquired motivation to the schedule-induced polydipsia paradigm and more generally to adjunctive behavior. The theory suggests that manipulations of the quality and the size of the pellet presented on an intermittent schedule should be important modulators of polydipsia. In Experiment 1, presenting animals with preferred, less preferred, or least preferred food pellets on a fixed-time 120-sec schedule resulted in progressively lower levels of water intake. In Experiment 2, the quality and size of the pellet were manipulated factorially. These variables were found to interact in the control of both the development and maintenance of schedule-induced drinking. Thus, predictions from the opponent-process theory were supported by these findings.     

Processing level and recognition: A search method for inducing alternative encodings of unrelated words

Twenty-four subjects viewed cards containing four words. In synonym orienting, half of the cards contained a synonym pair and half did not; in homophone orienting, half of the displays contained a homophone pair. The remaining two words in each display were used to index retention. During presentation of displays, subjects responded “yes” or “no” to indicate the presence or absence of a matching pair. Following presentation, a recognition test was administered. Half the items were tested early and half were tested late; within each test order, half the items appeared with context cues during testing and half appeared without. Results showed superior recognition (1) following semantic orienting, (2) for items tested early, (3) for items tested with context, and (4) for nonmatch displays requiring exhaustive item comparison. An Orienting by Test Cuing interaction showed that the presence of test cues improved recognition for homophone orienting items only. The interaction may have resulted from the lack of cuetarget associations and the reinstatement of the phonemic orienting set during the test.