Coping with challenge and hindrance stressors in teams: Behavioral,cognitive, and affective outcomes

The purpose of this study was to utilize the challenge–hindrance framework to examine the discrete and combined effects of different environmental stressors on behavioral, cognitive, and affective outcomes at the team level. Results from 83 teams working on a command and control simulation indicated that the introduction of a challenge stressor positively affected team performance and transactive memory. The introduction of a hindrance stressor negatively affected team performance and transactive memory and positively affected psychological withdrawal. When the hindrance stressor was combined with the challenge stressor, teams exhibited the lowest levels of performance and transactive memory, and the highest levels of psychological withdrawal. These effects were due to the adoption of specific coping strategies by team members. Implications are discussed, as well as limitations and directions for future research.     

老年人记忆补偿的长期稳定性和变异性：来自维多利亚纵向研究的证据

两种记忆状况组来自于参与加拿大维多利亚纵向研究(VLS)的老年人原样本。一种是未受损伤的控制组(NIC), 另一种是轻度记忆损伤组(MMD)。在基线水平和纵向水平上(即5次追踪或12年)比较了他们在日常生活中对记忆补偿技术的使用。我们使用多水平模型(以年龄和教育水平为协变量)来检验基线水平的差异和长期的变化模式。基线的结果表明MMD组被试报告了近期在日常生活中使用记忆补偿策略方面有更大的增长。纵向的结果表明记忆补偿的使用在12年中具有明显的稳定性, 但是与努力相关的补偿机制存在显著组间差异。教育水平这一协变量(可认为是潜在的认知储备指标)和三种记忆补偿策略随时间的不同变化相关。     

东莨菪碱对大鼠空间参考记忆和工作记忆的不同影响

观察东莨菪碱对空间参考记忆和空间工作记忆的编码、保持和提取过程的作用。应用Morris水迷宫实验测定大鼠的空间参考记忆和空间工作记忆,分别在训练的不同阶段腹腔注射东莨菪碱（1mg/kg）和相同容量的生理盐水,比较各东莨菪碱组和生理盐水组之间游泳潜伏期、路径长度、轨迹和游泳速度的差异。结果发现：与注射生理盐水相比,在训练前和探测实验前注射东莨菪碱的大鼠在探测实验中对目标象限不表现出空间偏爱,说明东莨菪碱干扰参考记忆的信息编码和提取过程;而在训练结束后注射东莨菪碱的大鼠探测实验的结果与生理盐水组相比没有显著差异,说明东莨菪碱对参考记忆的保持过程没有影响。在工作记忆实验中,无论第一次测试前、第一次测试后和第2次测试前注射东莨菪碱,均造成大鼠游泳潜伏期延长,说明东莨菪碱干扰工作记忆的编码、保持和提取过程。研究提示M受体在空间工作记忆和参考记忆中发挥不同作用     

A model of working memory capacity in the radial-arm maze task

The radial arm maze is one of the most commonly used tests for assessing working memory in laboratory animals. However, to date, there exists no quantitative method of estimating working memory capacity from performance on this task. Here, we present a mathematical model of performance on the radial arm maze from which we can derive estimates of capacity. We derive explicit results for the two most commonly used measures of performance as functions of number of arms in the maze and memory capacity, assuming a uniform random search. We simulate random non-uniform search strategies. Comparing our model to previous experiments, we show that our model predicts a working memory capacity in the range of 3-9 at the level of performance observed in these experiments. This estimate is within the typical estimate of human working memory capacity. Performance of rats on large mazes (e.g. 48 arms) has been used as evidence that the working memory capacity of rats may be significantly larger than that of humans. We report that memory capacity in the range 3-9 is sufficient to explain the performance of rats in very large radial mazes. Furthermore, when we simulate non-uniform random search strategies observed in the experiments, the resulting estimates do not differ significantly from those assuming a uniform random search. We conclude that a list-based model of working memory with modest capacity is more powerful than previously expected.     

Neural correlates of variable working memory load across adult age and skill: dissociative patterns within the fronto-parietal network

We examined neural changes related to variations in working memory load by using an n -back task with three levels and functional magnetic resonance imaging. Younger adults were divided into high- and low-performing groups (Young-High; Young-Low) and compared with older adults. Relative to Young-High, capacity-constraints in working memory were apparent between load 1–2 for the elderly and between load 2–3 for Young-Low. Capacity-constraints in neural activity followed this pattern by showing a monotonically increasing response in parietal cortex and thalamus for Young-High, whereas activity leveled off at 1-back for the elderly and at 2-back for Young-Low. The response in dorsal frontal cortex followed a similar pattern with the addition that the magnitude of activation differed within capacity limitations (Old > Young at 1-back; Young-Low > Young-High at 2-back). These findings indicate that an important determinant of WM capacity is the ability to keep the frontal cortex adequately engaged in relation to current task demands.     

The Signal-Cognition interface: Interactions between degraded auditory signals and cognitive processes

A hearing loss leads to problems with speech perception; this is exacerbated when competing noise is present. The speech signal is recognized by the cognitive system of the listener; noise and distortion tax the cognitive system when interpreting it. The auditory system must interact with the cognitive system for optimal signal decoding. This article discusses this interaction between the signal and cognitive system based on two models: an auditory model describing signal transmission and degeneration due to a hearing loss and a cognitive model for Ease of Language Understanding. The signal distortion depends on the specifics of the hearing impairment and thus differently distorted signals can affect the cognitive system in different ways. Consequently, the severity of a hearing loss may not only depend on the lesion itself but also on the cognitive recourses required to interpret the signal.     

Cognition and hearing aids

The perceptual information transmitted from a damaged cochlea to the brain is more poorly specified than information from an intact cochlea and requires more processing in working memory before language content can be decoded. In addition to making sounds audible, current hearing aids include several technologies that are intended to facilitate language understanding for persons with hearing impairment in challenging listening situations. These include directional microphones, noise reduction, and fast-acting amplitude compression systems. However, the processed signal itself may challenge listening to the extent that with specific types of technology, and in certain listening situations, individual differences in cognitive processing resources may determine listening success. Here, current and developing digital hearing aid signal processing schemes are reviewed in the light of individual working memory (WM) differences. It is argued that signal processing designed to improve speech understanding may have both positive and negative consequences, and that these may depend on individual WM capacity.     

Overweight and cognition

There is a growing concern among health authorities that an increasing number of people in the Western world become overweight and even obese. It is well known that obesity is related to several diseases (e.g., diabetes, stroke, and high blood pressure) and that such diseases related to obesity lead to early death. It has also been discussed whether overweight and obesity in themselves or in relation to such diseases lead to cognitive decline. On the basis of data from a large, population‐based, prospective study we examined three cognitive domains: episodic memory, semantic memory, and spatial ability. Two body measures were used to define normal weight and overweight, body‐mass index and waist/hip ratio. Although these two body measures reveal quite different prevalence data of overweight, the associations between overweight and cognition are similar. For episodic memory, overweight interacts with age, but when controlling for hypertension, stroke and diabetes, this interaction disappears. For semantic memory, normal weight participants outperform overweight participants even after controlling for these diseases. For spatial ability, the well‐established advantage for men holds for young‐old and old‐old normal‐weight participants. For overweight participants, this advantage holds for middle‐age participants only. We conclude that there is a weight‐cognition relationship even after controlling for obesity‐related diseases. The results are discussed in terms of possible biological mechanisms.     

Cognition and aided speech recognition in noise: Specific role for cognitive factors following nine-week experience with adjusted compression settings in hearing aids

The working memory model for Ease of Language Understanding (ELU) proposes that language understanding under taxing conditions is related to explicit cognitive capacity. We refer to this as the mismatch hypothesis, since phonological representations based on the processing of speech under established conditions may not be accessed so readily when input conditions change and a match becomes problematic. Then, cognitive capacity requirements may differ from those used for processing speech hitherto. In the present study, we tested this hypothesis by investigating the relationship between aided speech recognition in noise and cognitive capacity in experienced hearing aid users when there was either a match or mismatch between processed speech input and established phonological representations. The settings in the existing digital hearing aids of the participants were adjusted to one of two different compression settings which processed the speech signal in qualitatively different ways ("fast" or "slow"). Testing took place after a 9-week period of experience with the new setting. Speech recognition was tested under different noise conditions and with match or mismatch (i.e. alternative compression setting) manipulations of the input signal. Individual cognitive capacity was measured using a reading span test and a letter monitoring test. Reading span, a reliable measure of explicit cognitive capacity, predicted speech recognition performance under mismatch conditions when processed input was incongruent with recently established phonological representations, due to the specific hearing aid setting. Cognitive measures were not main predictors of performance under match conditions. These findings are in line with the ELU model.     

认知加工偏向视野下的自尊研究

目前,关于自尊与认知相互作用关系的研究主要集中在认知加工偏向效应的探讨上。认知加工偏向效应的探索为自尊研究提供了一种全新的视角。该文以认知加工过程为脉络,重点介绍自尊的注意、记忆、解释加工偏向研究的实验范式和研究结果,并对其进行评价,以期为后来研究提供参考。