Analysis of distractor difficulty in multiple-choice items

Two psychometric models are presented for evaluating the difficulty of the distractors in multiple-choice items. They are based on the criterion of rising distractor selection ratios, which facilitates interpretation of the subject and item parameters. Statistical inferential tools are developed in a Bayesian framework: modal a posteriori estimation by application of an EM algorithm and model evaluation by monitoring posterior predictive replications of the data matrix. An educational example with real data is included to exemplify the application of the models and compare them with the nominal categories model.This research was supported by the DGI grant BSO2002-01485.I would like to thank Eric Maris and Vicente Ponsoda for their advice, Juan Botella for providing the data for the empirical application, and three anonymous reviewers for their comments that were essential for improving the quality of the paper.     

Operationalizing the "vulnerability" and "stress" components of the hopelessness theory of depression: a multi-wave longitudinal study

The current study tested of the diathesis-stress component of the hopelessness theory (HT) using (1) a "weakest link" approach towards operationalizing vulnerability (e.g., an individual is as vulnerable to depression as his/her most depressogenic inferential style-DIS) and (2) an idiographic approach towards operationalizing high levels of stress. The procedure involved an initial assessment during which participants completed measures assessing DISs and depressive symptoms. The procedure also involved a series of eight follow-up assessments, occurring every 6 weeks, during which depressive symptoms and hassles were assessed. Hypotheses were tested in two samples of adults (i.e., adults diagnosed with a current MDE and adults diagnosed with a past MDE at Time 1). In line with hypotheses, in both samples, depressogenic weakest links were associated with greater elevations in depressive symptoms following elevations in hassles. At the same time, equally strong support was obtained for the HT when stress was operationalized from a nomothetic perspective and when vulnerability was operationalized as a DIS about causes (but not consequences or self).     

Enhancing job-site training of supported workers with autism: a reemphasis on simulation

Currently recommended practice in supported work emphasizes training job skills to workers with severe disabilities while on the job. Early behavioral research indicated that skills needed in natural environments could also be trained in simulated settings. We compared job-site plus simulation training for teaching job skills to supported workers with autism to provision of training exclusively on the job. Job-site training occurred in a small publishing company during the regular work routine, and simulation training occurred in an adult education site for people with severe disabilities. Two pairs of workers received training on two job skills; one skill was trained at the job site and the other was trained using job-site plus simulation training. Results indicated that for 3 of the 4 comparisons, job-site plus simulation training resulted in a higher level of skill or more rapid skill acquisition than did job-site-only training. Results suggested that job-site training, the assumed best practice for teaching vocational skills, is likely to be more effective if supplemented with simulation training. Directions for future research include expanding applications of behavioral technologies to other aspects of the current support paradigm.     

Modeling recognition memory using the similarity structure of natural input

The natural input memory (NIM) model is a new model for recognition memory that operates on natural visual input. A biologically informed perceptual preprocessing method takes local samples (eye fixations) from a natural image and translates these into a feature-vector representation. During recognition, the model compares incoming preprocessed natural input to stored representations. By complementing the recognition memory process with a perceptual front end, the NIM model is able to make predictions about memorability based directly on individual natural stimuli. We demonstrate that the NIM model is able to simulate experimentally obtained similarity ratings and recognition memory for individual stimuli (i.e., face images).     

Need Satisfaction as a Mediator of Associations between Interparental Relationship Dimensions and Autonomy Supportive Parenting: A Weekly Diary Study

Guided by the self-determination theory, this weekly diary study tested a process model in which week-to-week mother-reported interparental conflict and perceived partner responsiveness were associated with maternal autonomy support by means of maternal psychological need satisfaction. During six consecutive weeks, 258 mothers (M_age = 41.71 years) and their 157 adolescents (51.4% females, M_age = 14.92 years) from Turkey provided weekly reports of the study variables via an online survey. Multilevel analyses showed that maternal need satisfaction was predicted by lower levels of interparental conflict and greater levels of perceived partner responsiveness. Maternal need satisfaction, in turn, was positively associated with maternal and adolescent reports of maternal autonomy support. Further, these week-to-week associations were partly moderated by maternal perfectionism. The results underscore the dynamic nature of the intra-family relationships, the important role of particular conditions in which mothers may become more autonomy supportive, and the necessity to consider mother’s personal characteristics while examining these dynamics.     

右视野颜色范畴知觉是长期习得语言范畴还是即时分类颜色的结果?

本研究探讨了右视野颜色范畴知觉是由长期习得语言范畴还是即时分类颜色引起的。实验1让被试先将深绿、浅绿、浅蓝和深蓝四种颜色分为四种范畴,再接受视觉搜索任务。结果发现,视觉搜索任务中出现了与颜色分类相应的右视野颜色范畴知觉,且这一效应在任务的早段就表现出来,提示右视野颜色范畴知觉并非由分类颜色所引起。实验2让被试将四种渐进的蓝色分为两种范畴,并在之前与后接受视觉搜索任务。结果表明,分类后的视觉搜索中并未出现右视野颜色范畴知觉。先前研究表明,习得语言范畴使四种颜色为两种范畴后,颜色辨别会出现右视野范畴效应。因此,这一结果提示右视野颜色范畴知觉并非由分类颜色,而是由习得语言范畴所引起的。总体上,本研究提示右视野颜色范畴知觉是由长期习得语言范畴,而非即时分类颜色引起的,进一步揭示了语言与颜色知觉的关系。     

Infiltration behaviour of water in a carbon nanotube under external pressure

The wetting behaviour and associated pressure effect of water in single-walled carbon nanotubes (SWCNTs) are investigated through molecular dynamics (MD) simulations. It is found that water molecules can enter SWCNTs via surface diffusion, and the effective infiltration rate increases with pressure. The effect of pressure on infiltration rate is highly non-linear, exhibiting characteristics of both hydrophilic and hydrophobic surfaces. There exists a nominal infiltration pressure that is dependent on the SWCNT size, above which the water flux is significantly increased.     

Flaw tolerance promoted by dissipative deformation mechanisms between material building blocks

Novel high-performance composite materials often draw inspiration from natural materials such as bone or mollusc shells. A prime feature of such composites is that they are, like their natural counterparts, quasibrittle. They are tolerant to material flaws up to a certain characteristic flaw-tolerant size scale, exhibiting high strength and toughness, but start to behave in a brittle manner when sufficiently large flaws are present. Here, we establish that better flaw tolerance can be achieved by maximizing fracture toughness relative to the maximum elastic energy available in the material, and we demonstrate this concept with simple two-dimensional coarse-grained simulations where the transition from brittle to quasibrittle behaviour is examined.