Identification of biological neurons using adaptive observers

Change detection performance is influenced by a number of factors, among which is the informativeness of targets. It has not been clarified, yet, whether the highly informative regions have a processing priority as a result of resource deployment from other tasks or whether it results from a better resource management. In this paper, we adopted a change detection paradigm in which thirty participants were randomly assigned to two groups: single (change detection task) and dual task [change detection and a simplified version of the Paced Auditory Serial Oppository Task (PASOT, Gow and Deary in J Clin Exp Neuropsychol 26:723–736, 2004), which implies a verbal effort]. Stimulus informativeness was defined as social relevance, that is, changing targets were people (high relevance) versus objects (low relevance), all other aspects (i.e., salience and position in the scene) kept constant. As hypothesized, data analyses showed a significant main effect of social relevance and task condition, i.e., better change detection performance and lower change detection times for people versus objects and for single than for dual task condition. Interestingly, the PASOT accuracy remained stable across the person versus object trials, thus implying that the better performance with socially relevant targets could not be explained by a resources withdrawal from the secondary task.

Analytic Expressions for the BCDMEM Model of Recognition Memory

We introduce a Fourier transformation technique that enables one to derive closed-form expressions of performance measures (e.g., hit and false alarm rates) of simulation-based models of recognition memory. Application of the technique is demonstrated using the bind cue decide model of episodic memory (BCDMEM; [Dennis, S., & Humphreys, M.S. (2001). A context noise model of episodic word recognition. Psychological Review, 108(2), 452-478]). In addition to reducing the time required to test the model, which for models like BCDMEM can be excessive, asymptotic expressions of the measures reveal heretofore unknown properties of the model, such as model predictions being dependent on vector length.     

Visual marking and change detection

The preview benefit from prior exposure of response-irrelevant (distracter) objects in visual search has been accounted for in terms of top-down inhibition (i.e. visual marking), bottom-up abrupt onset capture, or asynchrony-dependent perceptual segregation. We assess the relative contribution of abrupt onset and visual marking in a paradigm combining visual search with a visual working memory task. We investigated time-based selection of multiple objects for storage in visual working memory, using a change detection paradigm (Luck and Vogel in Nature 390:279–281, 1997) with distracter preview. We varied preview exposure (short vs. long), in a series of three experiments. The contribution of asynchrony-related perceptual segregation was assessed across experiments by varying the complexity of the stimuli (colored squares, oriented bars and oriented T-shapes) and the type of change detection (color or orientation), resulting in different levels of perceptual segregation between visual elements. The results suggest that bottom-up abrupt onset, visual marking and perceptual segregation factors co-operate in time-based selection for storage in visual working memory.     

Visual Signal Detection Measured by Event-Related Potentials

Signal Detection tasks typically involve within-subject signal changes. Such a procedure does not lend itself to event-related potential (ERP) experiments where the need for averaging necessitates the maintenance of consistent stimulus parameters. In the present ERP study we adopt a novel approach to thresholding that allows within-subject signal manipulation. The Signal Detection task required the identification of letter targets, formed from dots, in a random dot field. ERP waveforms were segmented into three windows corresponding to N1, N2, and P300 components. Analysis shows that ERP variations are dependent on both task demands and response characteristics for N1, N2, and P300 components.     

Functional visual field in a rapid serial visual presentation task

Dynamic temporal change in the size of functional visual field was measured using a dual task: a peripheral task in which one square in a background pattern of squares was changed in shape to a dot; and a central task involving the rapid serial visual presentation of a sequence of letters (RSVP task). The temporal lag between the occurrences of the dot and the RSVP target was manipulated. University students were asked to detect the dot and to depress a mouse button as quickly as possible while searching for the RSVP target among a sequence of distracter letters. The abrupt change in the shape of a background square in the peripheral task caused a processing deficit in the RSVP task at relative lags from –3 to –1 (255 ms to 85 ms before presentation of the RSVP target), but the encoding and retaining processes involved in identifying the RSVP target did not impair the detection of the peripheral dot. The functional visual field was found to expand while participants were performing the dual task, suggesting that preattentive detection is affected by general attentional activity.     

视觉监控作业中信号间隔时间和双任务对信号觉察的影响

本研究运用模拟实验,考察了以仪表显示为主的监控系统中信号间隔时间和双作业任务对人觉察信号的反应时间的影响.双作业中的主任务是要求被试同时监视4个仪表,次任务为对显示屏上一个红色亮点是否出现闪烁作简单的辨别反应.实验结果表明信号间隔时间是影响信号觉察反应时的一个重要因素.随着信号间隔时间由30-50秒延长到8-10分钟,信号觉察反应时随之先快后慢地增加.在低负荷的仪表监视作业中,通过增加一个刺激率较高而又比较简单的次任务,可使被试保持较高的唤醒水平和更好地集中注意,从而有利于提高信号觉察效率.     

驾驶员视觉注意对危险识别的影响及作用机制

驾驶中, 有效的视觉注意模式是驾驶员搜索与识别潜在道路危险的先决条件。通过分析驾驶员视觉注意对危险识别的影响, 提出情境意识假设与心理负荷假设。情境意识假设认为, 情境意识的质量决定了驾驶员视觉注意模式的灵活性, 进而影响危险识别。心理负荷假设认为, 心理负荷水平提高, 驾驶员视觉注意趋于集中, 不利于危险识别。建议未来研究可以在比较不同驾驶员情境意识的认知兼容性, 应用汽车驾驶自动化技术降低心理负荷以及检测并区分情境意识与心理负荷的影响等方面加以深入。     

简论里贝特的意识理论

里贝特是人类意识和自由意志的实验研究领域的一个卓越的、先驱性的神经科学家。里贝特的意识研究工作涉及如下四个方面：（1）关于意识研究的认识论原则;（2）对意识现象本性的界定;（3）意识机制的时控理论;（4）对自由意志的阐释和有意识的心智场理论。里贝特的意识研究独树一帜,其时控理论具有坚实可信的实验证据,它从时间维度揭示了有意识的主观体验以及无意识的心智功能与神经活动之间的时间机制。     

判断与决策中的基线比例忽略

基线比例忽略是指在事件的判断中忽略相关事件统计学上的信息, 而只关注当前呈现的案例信息, 从而造成判断和决策偏差的一种现象。目前对这一现象的解释主要包括双加工理论和线性整合理论, 而影响基线比例忽略的因素有许多方面, 如信息特征、认知能力等等。在未来研究中, 应该深入分析双加工理论的作用机制以及依据模糊痕迹理论提出新的研究视角, 同时拓展在团体和公共领域中的应用性研究。     

Aligning Spinoza with Descartes: An informed Cartesian account of the truth bias

There is a bias towards believing information is true rather than false. The Spinozan account claims there is an early, automatic bias towards believing. Only afterwards can people engage in an effortful re‐evaluation and disbelieve the information. Supporting this account, there is a greater bias towards believing information is true when under cognitive load. However, developing on the Adaptive Lie Detector (ALIED) theory, the informed Cartesian can equally explain this data. The account claims the bias under load is not evidence of automatic belief; rather, people are undecided, but if forced to guess they can rely on context information to make an informed judgement. The account predicts, and we found, that if people can explicitly indicate their uncertainty, there should be no bias towards believing because they are no longer required to guess. Thus, we conclude that belief formation can be better explained by an informed Cartesian account – an attempt to make an informed judgment under uncertainty.