Cognitive functioning in delusions: a longitudinal analysis

BACKGROUND: This study explored the longitudinal course of the relationship between delusions and different aspects of cognitive functioning. METHODS: Deluded patients were compared to psychiatric and non-clinical controls on three tasks: negative priming, a probabilistic judgement task (the 'beads' task), and the pragmatic inference task (PIT). All groups were tested at two time points, once when actively symptomatic, and once when in remission. RESULTS: Deluded individuals exhibited a 'jump-to-conclusions' (JTC) reasoning bias: i.e., they made decisions on the basis of limited evidence and were more likely to revise their estimates when faced with disconfirmatory evidence. This JTC bias remained stable over time, although probability judgments seemed to normalise in remission. No deficits in cognitive inhibition were found on negative priming. The deluded group displayed an excessive self-focus on the PIT at both time points, but did not show a depressive attributional style. Only a small sub-sample, characterised by the "bad-me" type of paranoia [Trower & Chadwick, 1995 Clinical Psychology: Science and Practice, 2, 263-278.], demonstrated depressive schemas when symptomatic, but no longer did so when remitted. Few relationships were found between tasks, suggesting that different areas of functioning are relatively independent. The only measures associated with delusion symptom scores were from the 'beads' task. CONCLUSIONS: Overall these findings suggest that the JTC bias is a stable factor associated with delusional thinking, while the depressive attributional style characteristic of a small sub-sample of paranoid patients fluctuates with delusional course.     

Cognitive inhibition and interference in dissociative identity disorder: the effects of anxiety on specific executive functions

Using an experimentally based, computer-presented task, this study assessed cognitive inhibition and interference in individuals from the dissociative identity disorder (DID; n=12), generalized anxiety disorder (GAD; n=12) and non-clinical (n=12) populations. Participants were assessed in a neutral and emotionally negative (anxiety provoking) context, manipulated by experimental instructions and word stimuli. The DID sample displayed effective cognitive inhibition in the neutral but not the anxious context. The GAD sample displayed the opposite findings. However, the interaction between group and context failed to reach significance. There was no indication of an attentional bias to non-schema specific negative words in any sample. Results are discussed in terms of the potential benefit of weakened cognitive inhibition during anxious arousal in dissociative individuals.     

Behavioural inhibition, anxious symptoms, and depressive symptoms: a short-term prospective examination of a diathesis-stress model

The purpose of the current study was to examine the relationship between behavioural inhibition (BI) and anxious symptoms within a diathesis-stress framework, using a short-term prospective design. In addition, we examined whether BI acts as a specific vulnerability to anxious symptoms, or as a common vulnerability to both anxious and depressive symptoms. At time 1, 384 children in grades 3 through 6 completed self-report measures of BI, anxious symptoms, and depressive symptoms. Six weeks later, they completed self-report measures of hassles, anxious symptoms, and depressive symptoms. Results demonstrated that children with high BI who experienced high levels of hassles during the 6-week follow-up interval showed increases in anxious symptoms, but not depressive symptoms.     

Some effects of stimulant medication on response allocation: a double-blind analysis

Children who are diagnosed with attention deficit hyperactivity disorder (or who engage in behavior consistent with such a diagnosis) are often prescribed stimulant medications for hyperactive or inattentive behaviors. However, the mechanisms by which stimulant medications affect individuals' behavior are rarely evaluated. The purpose of the current study was to evaluate the effects of stimulant medication on response allocation when antecedents and consequences were held constant and equated. Results indicated that the presence of an amphetamine medication (Adderall) influenced response allocation across two concurrently available responses while all other stimulus conditions were held constant.     

Sexual Attitudes and Instructional Set Affect Estimates of Risk and Response Effectiveness

Two hundred and eleven undergraduate men and women were assigned to different instructional set conditions and asked to rate (1) the sexual risk depicted in a set of written items describing problem situations undergraduate women might face when dating or interacting socially with men, and (2) the effectiveness of responses to these situations, described by a set of response codes. Results revealed that sexual attitudes and instructional set were the strongest predictors of both ratings. Gender did, however, predict risk ratings for stranger and authority figure situations, with women rating these situations as more risky than men. In addition, women assigned to the risk instructional set condition rated refusal responses as more effective in decreasing risk than did men in the same condition. In contrast, women assigned to the popularity instructional set condition rated the same refusal responses as less effective in increasing popularity than did men in that condition.

Challenges using motivational interviewing as an adjunct to exposure therapy for obsessive-compulsive disorder

Exposure and response prevention (EX/RP) is an efficacious treatment for obsessive-compulsive disorder (OCD). However, patients often do not adhere fully to EX/RP procedures. Motivational interviewing (MI) has been shown to improve treatment adherence in other disorders. This pilot study used a randomized controlled design to examine whether MI can be successfully added to EX/RP and whether this intervention (EX/RP + MI) could improve patient adherence to between-session EX/RP procedures relative to EX/RP alone. Thirty adults with OCD were randomized to 18 sessions of EX/RP or EX/RP + MI. Therapists rated patient adherence at each exposure session. Independent evaluators assessed change in OCD and depressive symptoms, and patients completed self-report measures of readiness for change and quality of life. The two treatment conditions differed in degree of congruence with MI but not in conduct of EX/RP procedures. Both groups experienced clinically significant improvement in OCD symptoms, without significant group differences in patient adherence. There are several possible reasons why EX/RP + MI had no effect on patient adherence compared to standard EX/RP, each of which has important implications for the design of future MI studies in OCD. We recommend that MI be further evaluated in OCD by exploring alternative modes of delivery and by focusing on patients less ready for change than the current sample.     

Stimulus disparity and punisher control of human signal-detection performance

The present experiment examined the effects of varying stimulus disparity and relative punisher frequencies on signal detection by humans. Participants were placed into one of two groups. Group 3 participants were presented with 1:3 and 3:1 punisher frequency ratios, while Group 11 participants were presented with 1:11 and 11:1 punisher frequency ratios. For both groups, stimulus disparity was varied across three levels (low, medium, high) for each punisher ratio. In all conditions, correct responses were intermittently reinforced (1:1 reinforcer frequency ratio). Participants were mostly biased away from the more punished alternative, with more extreme response biases found for Group 11 participants compared to Group 3. For both groups, estimates of discriminability increased systematically across the three disparity levels and were unaffected by the punisher ratios. Likewise, estimates of response bias and sensitivity to the punisher ratios were unaffected by changes in discriminability, supporting the assumption of parameter invariance in the Davison and Tustin (1978) model of signal detection. Overall, the present experiment found no relation between stimulus control and punisher control, and provided further evidence for similar but opposite effects of punishers to reinforcers in signal-detection procedures.     

Conditioned reinforcement and response strength

Stimuli associated with primary reinforcers appear themselves to acquire the capacity to strengthen behavior. This paper reviews research on the strengthening effects of conditioned reinforcers within the context of contemporary quantitative choice theories and behavioral momentum theory. Based partially on the finding that variations in parameters of conditioned reinforcement appear not to affect response strength as measured by resistance to change, long-standing assertions that conditioned reinforcers do not strengthen behavior in a reinforcement-like fashion are considered. A signposts or means-to-an-end account is explored and appears to provide a plausible alternative interpretation of the effects of stimuli associated with primary reinforcers. Related suggestions that primary reinforcers also might not have their effects via a strengthening process are explored and found to be worthy of serious consideration.     

A Bayesian-optimal principle for learner-friendly adaptation in learning games

Adaptive learning games should provide opportunities for the student to learn as well as motivate playing until goals have been reached. In this paper, we give a mathematically rigorous treatment of the problem in the framework of Bayesian decision theory. To quantify the opportunities for learning, we assume that the learning tasks that yield the most information about the current skills of the student, while being desirable for measurement in their own right, would also be among those that are efficient for learning. Indeed, optimization of the expected information gain appears to naturally avoid tasks that are exceedingly demanding or exceedingly easy as their results are predictable and thus uninformative. Still, tasks that are efficient for learning may be experienced as too challenging, and the resulting failures can lower motivation. Therefore, in addition to quantifying the expected informational benefit for learning of any prospective task to be presented next, we also model the expected motivational cost of its presentation, measured simply as the estimated probability of failure in our example model. We propose a “learner-friendly” adaptation algorithm that chooses the learning tasks by optimizing the expected benefit divided by the expected cost. We apply this algorithm to a Rasch-like student model implemented within a real-world application and present initial results of a pilot experiment.     

On the Speed Sensitivity Parameter in the Lognormal Model for Response Times and Implications for High-Stakes Measurement Practice

In high-stakes testing, often multiple test forms are used and a common time limit is enforced. Test fairness requires that ability estimates must not depend on the administration of a specific test form. Such a requirement may be violated if speededness differs between test forms. The impact of not taking speed sensitivity into account on the comparability of test forms regarding speededness and ability estimation was investigated. The lognormal measurement model for response times by van der Linden was compared with its extension by Klein Entink, van der Linden, and Fox, which includes a speed sensitivity parameter. An empirical data example was used to show that the extended model can fit the data better than the model without speed sensitivity parameters. A simulation was conducted, which showed that test forms with different average speed sensitivity yielded substantial different ability estimates for slow test takers, especially for test takers with high ability. Therefore, the use of the extended lognormal model for response times is recommended for the calibration of item pools in high-stakes testing situations. Limitations to the proposed approach and further research questions are discussed.