Why Dynamical Self-Excitation Is Possible

In Pérez Laraudogoitia (1996), I introduced a simple example of a supertask that involved the possibility of spontaneous self-excitation and, therefore, of a particularly interesting form of indeterminism in classical dynamics. Alper and Bridger (1998) criticised (among other things) this result. In the present article, I answer their criticisms. In what follows I assume familiarity both with Pérez Laraudogoitia (1996) and Alper and Bridger’s subsequent article. This revised version was published online in June 2006 with corrections to the Cover Date.     

Predictors of moderated drinking in a primarily alcohol-dependent sample of men who have sex with men

Understanding for whom moderated drinking is a viable, achievable, and sustainable goal among those with a range of alcohol use disorders (AUD) remains an important public health question. Despite common acceptance as severe risk factors, there is little empirical evidence to conclude whether co-occurring mental health disorders or drug dependence contribute to an individual's inability to successfully moderate his drinking. Utilizing secondary data analysis, the purpose of this study was to identify predictors of moderation among both treatment-seeking and non-treatment-seeking, primarily alcohol-dependent, problem-drinking men who have sex with men (MSM), with an emphasis on the high risk factors psychiatric comorbidity and drug dependence. Problem drinkers (N = 187) were assessed, provided feedback about their drinking, given the option to receive brief AUD treatment or change their drinking on their own, and then followed for 15 months. Findings revealed that neither psychiatric comorbidity or drug dependence predicted ability to achieve moderation when controlling for alcohol dependence severity. Those who were younger, more highly educated, and had more mild alcohol dependence were more likely to achieve moderated drinking. Impact of treatment on predictors is explored. Limitations of this study and arenas for future research are discussed. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Effects of cage mesh on pointing: hand shapes in chimpanzees (<Emphasis Type="Italic">Pan troglodytes</Emphasis>)

It has been speculated that cage mesh exerts a shaping influence on reaching behavior by captive apes, which is then misconstrued as pointing by human observers. Although this notion is clearly falsified by the pointing of captive language-trained apes—who point in the absence of intervening cage mesh—nevertheless, the degree to which cage mesh might influence pointing hand shapes by captive great apes in other housing environments remains relatively unexplored. We examined 259 pointing gestures displayed in archival footage from over 18 h of observation by three nonlanguage-trained chimpanzees housed at a biomedical research center. We coded points in relation to how close to the boundaries of the diamond-shaped cage mesh their points were displayed. We found that points with the whole hand were significantly more likely to be displayed away from the mesh boundaries, relative to points with the index finger or other single-digit points. However, points of each hand shape were displayed at each location, demonstrating that these physical parameters do not fully account for the number of fingers extended while pointing by chimpanzees.     

Overperceiving disease cues: the basic cognition of the behavioral immune system

The behavioral immune system is designed to promote the detection and avoidance of potential sources of disease. Whereas previous studies of the behavioral immune system have provided insight into the types of heuristic cues used to identify disease carriers, the present research provides an understanding of the basic psychological processes involved in the detection of those cues. Across 4 studies, feeling vulnerable to disease, whether that feeling stemmed from dispositional tendencies or situational primes, facilitated a disease overperception bias--a tendency to overperceive people in the environment displaying heuristic disease cues. This disease overperception bias was observed in the outcomes of 2 cognitive processes: categorization and memory. When concerned about disease, participants set a lenient threshold for categorizing targets as displaying heuristic disease cues (e.g., obesity, old age). Additionally, concerns about disease led participants to set a lenient threshold for reporting on a recognition task that they had previously seen individuals displaying those disease cues. The present research provides insight into the basic cognitive mechanisms underlying the operation of the behavioral immune system.     

Don’t wait to incubate: Immediate versus delayed incubation in divergent thinking

Previous evidence for the effectiveness of immediate incubation in divergent creative tasks has been weak, because earlier studies exhibited a range of methodological problems. This issue is theoretically important, as a demonstration of the effects of immediate incubation would strengthen the case for the involvement of unconscious work in incubation effects. For the present experiment, we used a creative divergent-thinking task (alternative uses) in which separate experimental groups had incubation periods that were either delayed or immediate and that consisted of either spatial or verbal tasks. Control groups were tested without incubation periods, and we carried out checks for intermittent conscious work on the target task during the incubation periods. The results showed significant incubation effects that were stronger for immediate than for delayed incubation. Performance was not different between the verbal and spatial incubation conditions, and we found no evidence for intermittent conscious working during the incubation periods. These results support a role for unconscious work in creative divergent thinking, particularly in the case of immediate incubation.     

Metacognitive therapy in treatment-resistant depression: a platform trial

Patients with treatment-resistant depression received up to 8 sessions of metacognitive therapy (MCT) targeting attentional control, rumination, worry, and metacognitive beliefs. A baseline period was followed by weekly sessions with follow-up assessments at 6 and 12 months post treatment. Large and statistically significant improvements occurred in all symptom measures at post treatment and were maintained over follow-up. Two out of 3 process measures significantly improved at post treatment and all of these measures were improved at follow-up. Treatment was associated with similar response rates on the BDI and Hamilton rating scale. Using liberal criteria 80% of completers were classified as recovered at post treatment and 70% at follow-up on the BDI. In the intention to treat sample 66.6% were recovered at post treatment and 58.3% at follow-up. More stringent criteria showed 60% recovery rates at post treatment and at 12 m. The results suggest that MCT could be a brief and effective treatment and they provide a precedent for more definitive randomized controlled trials.     

Developing procedural flexibility: Are novices prepared to learn from comparing procedures?

Background. A key learning outcome in problem‐solving domains is the development of procedural flexibility, where learners know multiple procedures and use them appropriately to solve a range of problems (e.g., Verschaffel, Luwel, Torbeyns, & Van Dooren, 2009 ). However, students often fail to become flexible problem solvers in mathematics. To support flexibility, teaching standards in many countries recommend that students be exposed to multiple procedures early in instruction and be encouraged to compare them. Aims. We experimentally evaluated this recommended instructional practice for supporting procedural flexibility during a classroom lesson, relative to two alternative conditions. The alternatives reflected the common instructional practice of delayed exposure to multiple procedures, either with or without comparison of procedures. Sample. Grade 8 students from two public schools (N= 198) were randomly assigned to condition. Students had not received prior instruction on multi‐step equation solving, which was the topic of our lessons. Method. Students learned about multi‐step equation solving under one of three conditions in math class for about 3 hr. They also completed a pre‐test, post‐test, and 1‐month‐retention test on their procedural knowledge, procedural flexibility, and conceptual knowledge of equation solving. Results. Novices who compared procedures immediately were more flexible problem solvers than those who did not, even on a 1‐month retention test. Although condition had limited direct impact on conceptual and procedural knowledge, greater flexibility was associated with greater knowledge of both types. Conclusions. Comparing procedures can support flexibility in novices and early introduction to multiple procedures may be one important reason.     

Direct lexical control of eye movements in reading: evidence from a survival analysis of fixation durations

Participants' eye movements were monitored in an experiment that manipulated the frequency of target words (high vs. low) as well as their availability for parafoveal processing during fixations on the pre-target word (valid vs. invalid preview). The influence of the word-frequency by preview validity manipulation on the distributions of first fixation duration was examined by using ex-Gaussian fitting as well as a novel survival analysis technique which provided precise estimates of the timing of the first discernible influence of word frequency on first fixation duration. Using this technique, we found a significant influence of word frequency on fixation duration in normal reading (valid preview) as early as 145ms from the start of fixation. We also demonstrated an equally rapid non-lexical influence on first fixation duration as a function of initial landing position (location) on target words. The time-course of frequency effects, but not location effects was strongly influenced by preview validity, demonstrating the crucial role of parafoveal processing in enabling direct lexical control of reading fixation times. Implications for models of eye-movement control are discussed.