In Search of the ‘Angels of Death’: Conceptualising the Contemporary Nurse Healthcare Serial Killer

Focusing specifically upon nurses who commit serial murder within a hospital setting, this paper aims to establish insights into this particular subcategory of healthcare serial killer. In addition, the paper aims to test the usefulness of an existing checklist of behaviours among this group of serial murderers. Drawing upon existing lists of healthcare serial killers produced by other scholars as well as legal records and an online news archive, we identified and researched healthcare serial killer nurses, collating socio demographic and criminological data and applying the aforementioned checklist to each case. Our findings suggest that to date, the label ‘healthcare serial killer’ has been applied in too loose a manner, making the understanding of this phenomenon problematic. In further refining the definition and identifying the socio‐demographic and criminological characteristics of the victims, perpetrators and crimes, we have developed more specific and therefore useful insights for practitioners and identified a potentially useful checklist which, with revisions, could contribute towards preventative strategies and interventions. Copyright © 2014 John Wiley & Sons, Ltd.     

Age-related differences in sequence learning: Findings from two visuo-motor sequence learning tasks

The Serial Reaction Time Task (SRTT) is thought to assess implicit learning, which seems to be preserved with age. However, the reaction time (RT) measures employed on implicit-like tasks might be too unreliable to detect individual differences. We investigated whether RT-based measures mask age effects by comparing the performance of 43 younger and 35 older adults on SRTT and an explicit-like Predictive Sequence Learning Task (PSLT). RT-based measures (difference scores and a ratio) were collected for both tasks, and accuracy was additionally measured for PSLT. We also measured fluid abilities. The RT-difference scores indicated preserved SRTT and PSLT performance with age and did not correlate with fluid abilities, while ratio RT and the accuracy-based measures indicated age-related decline and correlated with fluid abilities. Therefore, RT-difference scores might mask individual differences, which compromises the interpretation of previous studies using SRTT.     

Substitutability between conditioned and primary reinforcers in discrimination acquisition.

Rats and pigeons were trained on a series of reversals of a conditional simultaneous discrimination. The percentage of reinforcement for correct trials was varied across reversals. When nonreinforced correct trials produced the same feedback as incorrect trials, the number of errors to reach an acquisition criterion was greater for smaller percentages of reinforcement, but the number of reinforcers required was either approximately constant or smaller for the smaller percentages. When a stimulus paired with food (the conditioned reinforcer) was added on nonreinforced correct trials, both measures were substantially decreased. When the same stimulus was presented, but without a history of food pairing, learning rate was similar to when no stimulus was presented on nonreinforced trials. The results provide direct evidence that conditioned reinforcers may substitute, although imperfectly, for a primary reinforcer, and that pairing with the primary reinforcer is a necessary condition for such substitutability to occur.     

压力事件对初中生抑郁的影响:网络使用动机与网络使用强度的作用

为探讨压力事件对初中生抑郁的影响以及网络使用动机和网络使用强度在其中的作用,采用生活事件量表,网络使用动机量表,网络使用强度量表和流调中心用抑郁量表对武汉市内两所中学的913名初中生进行调查。结果发现：（1）压力事件与网络使用动机、网络使用强度和抑郁均呈显著正相关; （2）压力事件正向预测网络使用动机与网络使用强度,网络使用动机正向预测网络使用强度,网络使用强度正向预测抑郁; （3）网络使用动机中,社会补偿动机正向预测抑郁,而好友联系动机与休闲娱乐动机负向预测抑郁; （4）压力事件通过网络使用动机和网络使用强度的链式中介作用影响抑郁。研究结果强调压力事件不仅可以直接影响初中生抑郁,还可以通过网络使用动机和网络使用强度间接影响初中生抑郁。     

序列依赖效应——一种全新的“历史效应”

自2014年来, 研究者在视觉加工中发现一种全新的历史效应——序列依赖效应(当前刺激加工向先前刺激方向偏移的吸引性加工偏差)。近期研究发现：该效应广泛存在于视觉加工的各个层面(既包括朝向、空间位置、数量等低级特征, 也包括身份、吸引力、美感等高级属性); 其来源极为复杂(包括感觉编码、高级皮层的反馈调节、工作记忆、决策模板、感知与决策的级联等), 反映出不同层次的过往加工痕迹向当前认知的投射。针对该效应的典型特征、影响因素、认知与神经机制, 已涌现大量研究, 同时也存在严重争论, 亟待研究者深入探讨和厘清。     

Independent effects of word concreteness and word valence on immediate serial recall

The present study examined the roles of word concreteness and word valence in the immediate serial recall task. Emotion words (e.g. happy) were used to investigate these effects. Participants completed study-test trials with 7-item study lists consisting of positive or negative words with either high or low concreteness (Experiments 1 and 2) and neutral (i.e. non-emotion) words with either high or low concreteness (Experiment 2). In serial recall performance, we replicated the typical item concreteness effect (concrete words are better recalled than abstract words) and obtained an item valence effect (positive/neutral words are better recalled than negative words). However, there was no concreteness × valence interaction. We conclude that both word valence and word concreteness independently contribute to the serial order retention of emotion words in the immediate serial recall task.     

Micro-position effects in visual short term memory

Short-term memory for visually presented eight-digit numbers was tested in a forced recall, read-and-dial task. The digits were presented non-grouped or grouped in 2+2+2+2 or 2+3+3 digit formats. Spatial grouping enhanced memory performance and produced local discontinuities in the serial position curves related to grouping format. These micro-position effects are explained in terms of the relative spatial distinctiveness of individual digits.     

An integrative model for the study of behavioral momentum.

Behavioral momentum is the product of response rate and resistance to change. The data on relative resistance to change are summarized for pigeons responding on single-key two-component multiple schedules, in the initial links of two-key multiple chained schedules, and in equivalent components of two-key serial schedules. For single-key procedures, the ratio of resistance to change in two schedule components is shown to depend on the ratio of reinforcer rates obtained in the presence of the component stimuli. For two-key procedures, the ratio of resistance to change in equivalent components is shown to depend on the ratio of reinforcer rates correlated with key locations. A model based on stimulus-reinforcer contingencies that combines the reinforcer rates in schedule components summed over key locations and reinforcer rates correlated with key locations summed over components, each expressed relative to the session average reinforcer rate, gives a good account of the data. An extension of the relative law of effect for multiple schedules fails to provide a complete account of resistance to change, but both approaches are needed for a comprehensive understanding of behavioral momentum.     

自我报告测量中项目前后关系效应的研究

本文指出了自我报告法中项目前后关系效应的普遍存在性及其危害性。讨论了用信息加工的观点对项目前后关系效应所作的认知上的理论解释,以及测量工具中促使产生这种项目前后关系效应的关键特征。同时也讨论了项目序列位置的作用。     

Estimating an unobserved component of a serial response time model

A method is developed for estimating the response time distribution of an unobserved component in a two-component serial model, assuming the components are stochastically independent. The estimate of the component's density function is constrained only to be unimodal and non-negative. Numerical examples suggest that the method can yield reasonably accurate estimates with sample sizes of 300 and, in some cases, with sample sizes as small as 100.The author wishes to thank David Kohfeld, Jim Ramsay, Jim Townsend and two anonymous referees for a number of useful and stimulating comments on an earlier version of this paper.