Within-subject testing of the signaled-reinforcement effect on operant responding as measured by response rate and resistance to change

Response rates under random-interval schedules are lower when a brief (500 ms) signal accompanies reinforcement than when there is no signal. The present study examined this signaled-reinforcement effect and its relation to resistance to change. In Experiment 1, rats responded on a multiple random-interval 60-s random-interval 60-s schedule, with signaled reinforcement in only one component. Response resistance to alternative reinforcement, prefeeding, and extinction was compared between these components. Lower response rates, and greater resistance to change, occurred in the component with the reinforcement signal. In Experiment 2, response rates and resistance to change were compared after training on a multiple random-interval 60-s random-interval 60-s schedule in which reinforcer delivery was unsignaled in one component and a response-produced uncorrelated stimulus was presented in the other component. Higher response rates and greater resistance to change occurred with the uncorrelated stimulus. These results highlight the significance of considering the effects of an uncorrelated signal when used as a control condition, and challenge accounts of resistance to change that depend solely on reinforcer rate.     

Mediating factors in the arousal-performance relationship

The arousal-performance relationship was investigated within a social facilitation experiment, in which two major task dimensions (cognitive-motor and difficulty) were manipulated and two arousal measures (palmar sweat and self-reports) were taken. Subjects (75 male and 75 female introductory psychology students) were randomly assigned to one of five audience conditions and one of three task difficulty levels. Each subject performed three tasks, which varied as to cognitive and motor requirements, under a uniform difficulty level. No significant differences were found on any arousal or performance measure due to the audience manipulation. Females were found to be more aroused by the audiences than males, on both arousal measures. When self-reported arousal scores were quintiled to create five post hoc arousal conditions, significant interactions between these conditions and task difficulty level were obtained for both the cognitive and motor tasks. (No significant differences were found using quintiled palmar sweat scores.) On the basis of the similar pattern of these interactions, it was concluded that the inverted-U function was obtained only on high-difficulty tasks.     

Dreaming and bereavement

Bereavement dreams provide an important, though seldom mentioned or recognized, component of the grief process. As the unconscious presses for recognition of the pain and extent of the loss, dream material is presented to help the bereft move to a new and integrative life position. Religious symbols present themselves to give the grieving a new sense of themselves as individuals and an expanding view of the world. Grief therapists have generally ignored this important component of the grief process, and as a result, little significant clinical research has been done. A comprehensive picture of bereavement will not be developed until increased attention is given to this important area.     

Investigating behavior inhibition in obsessive-compulsive disorder: Evidence from eye movements

We investigated the role of inhibition failure in Obsessive Compulsive Disorder (OCD) through an eye tracking experiment. Twenty-five subjects with OCD were recruited, as well as 25 with Generalized Anxiety Disorder (GAD) and 25 healthy controls. A 3 (group: OCD group, GAD group and control group) × 2 (target eccentricity: far and near) × 2 (saccade task: prosaccade and antisaccade) mixed design was used, with all participants completing two sets of tasks involving both prosaccade (eye movement towards a target) and antisaccade (eye movement away from a target). The main outcome was the eye movement index, including the saccade latency (the time interval from the onset of the target screen to the first saccade) and the error rate of saccade direction. The antisaccade latency and antisaccade error rates for OCDs were much higher than those for GADs and healthy controls. OCDs had longer latency and error rates for antisaccades than for prosaccades, and for far-eccentricity rather than near-eccentricity stimuli. These results suggest that OCDs experience difficulty with behavior inhibition, and that they have higher visual sensitivity to peripheral stimuli. In particular, they show greatest difficulty in inhibiting behavior directed towards peripheral stimuli.     

Characterizing the ADHD phenotype for genetic studies

The genetic study of ADHD has made considerable progress. Further developments in the field will be reliant in part on identifying the most appropriate phenotypes for genetic analysis. The use of both categorical and dimensional measures of symptoms related to ADHD has been productive. The use of multiple reporters is a valuable feature of the characterization of psychopathology in children. It is argued that the use of aggregated measures to characterize the ADHD phenotype, particularly to establish its pervasiveness, is desirable. The recognition of the multiple comorbidities of ADHD can help to isolate more specific genetic influences. In relation to both reading disability and conduct disorder there is evidence that genes may be involved in the comorbid condition that are different from pure ADHD. To date, progress with the investigation of endophenotypes for ADHD has been disappointing. It is suggested that extending such studies beyond cognitive underpinnings to include physiological and metabolic markers might facilitate progress.     

A critique of science and R&D-based models of endogenous growth

Conclusion We have argued against the conventional treatment of science from two directions: firstly, we show that its assumptions about the mechanics of technology transfer are at odds with what occurs in practice. Secondly, the predictions of models based on conventional assumptions receive little support empirically, and are on some occasions contradicted by the data. We believe that the weaknesses we have discussed prompt a re-analysis of science as the workings of invisible colleges. Moreover, we note that there appears, at present, to be no empirical or sound theoretical reason to suppose that, for reasons of economic growth, governments need fund science. the author of The Economic Laws of Scientific Research, Macmillan/St Martin’s Press, 1996.     

The Effects of Sad Mood on Reports of Parents’ Caregiving Behaviors

Two studies examined the hypothesis that recollections of parents’ child-rearing behaviors on the Parental Bonding Instrument (PBI: Parker, Tupling, & Brown, 1979) are influenced by current mood. Study 1 investigated the effects of sad versus neutral mood induction on PBI scores in 50 college students. Participants rated their parents as less caring following the sad mood induction than following the neutral induction. Study 2 investigated the effects of naturally occurring changes in depressive symptoms on PBI scores over a two month period. Changes in depressive symptoms correlated with changes in father care scores and tended to correlate with changes in mother care scores. Findings from both studies suggest that retrospective reports of parenting are susceptible to mood bias and highlight the limits of using cross sectional designs to explore the relationship between parenting and depression.     

Interference with judgments of control and attentional shift as a result of prior exposure to controllable and uncontrollable feedback

The experiment was carried out to determine whether exposure to an uncontrollable relationship between an action and its outcome during a non-aversive pretreatment phase would affect subsequent ratings of perceived control emitted by human participants. Its other aim was to investigate the effect of such pre-exposure on the attentional focus of humans on internal and external cues. Participants were assigned to one of three groups; an uncontrollable pretreatment, a controllable pretreatment, and no pretreatment. Participants exposed to uncontrollable outcomes (unsolvable problems) gave lower ratings of control over a produced outcome than the other two groups, indicating the interference with subsequent judgments of control. The exposure to uncontrollable outcomes also increased levels of distraction produced by an external cue in a reaction time experiment. Such an effect was not found in the groups who had not been exposed to uncontrollable outcomes. These dual effects are similar to those noted in non-humans subjected to uncontrollable outcomes.     

A reanalysis of the CARIN theory of conceptual combination

The competition among relations in nominals (CARIN) theory of conceptual combination (C. L. Gagné & E. J. Shoben, 1997) proposes that people interpret nominal compounds by selecting a relation from a pool of competing alternatives and that relation availability is influenced by the frequency with which relations have been previously associated with the modifying concept. The current authors derived relation frequencies by using a sample of compounds occurring in the British National Corpus and compared them with those derived by Gagné and Shoben. The authors demonstrated that the original relation frequencies are unrepresentative and that Gagne' and Shoben's technique for dichotomizing them into high and low is unreliable. In addition, the authors revealed anomalies in the mathematical instantiation of the CARIN model and showed that it does not provide evidence for competition among relations.     

Effect of a signalled delay between an action and outcome on human judgement of causality

Three experiments examined the influence of a stimulus inserted between an action (pressing the space bar of a computer) and an associated delayed outcome (a triangle lighting up on the screen) on ratings of the causal effectiveness of that action. In Experiment 1, subjects rated an action that produced an outcome immediately as more causally effective than an action that produced a delayed outcome. The rating of the causal effectiveness of an action that produced a delayed outcome in which the delay was filled by a stimulus was higher than the rating of actions that produced the outcome after an unsignalled delay. In Experiment 2, the effect of a stimulus presented uncorrelated with the action or the outcome was examined and found not to enhance the rating of causal effectiveness of an action that produced a delayed outcome. In Experiment 3, the degree of correlation between the stimulus and the consequence was examined. Ratings of the causal effectiveness of the action were greater the higher percentage of delay intervals that were signalled.