位置和轨迹信息在短暂消失目标复原过程中的作用

研究发现在多目标追踪任务中,即使视野中的所有物体同时消失长达几百毫秒,被试也能成功地完成追踪任务。Horowitz等（2006）认为这种能力主要是依靠把刺激消失时的目标信息保存在一种离线存储（off-line memory）记忆当中。这样,当刺激再现时,被试就可以把当前画面与存储的内容进行比较来区分目标和非目标。本研究的目的在于探讨目标位置、运动轨迹等信息在目标复原过程中的作用。结果发现：(1) 目标再现位置与消失位置相同时,被试的成绩最好,这说明在目标复原过程中利用了基于位置匹配的策略。(2)当目标再现位置与其消失前的运动方向一致或位于其消失前的运动轨迹上时,成绩较对照条件（目标再现于运动轨迹的法线方向）要好,这说明被试能够利用目标运动的轨迹和方向等信息。（3）当追踪的目标数量增加时,目标运动轨迹和方向等信息在复原过程中的相对作用下降,且被试只能利用1~2个目标的轨迹和运动方向信息     

习得的语言范畴影响颜色知觉的机制:来自ERP的证据

本研究以两个实验探讨了习得的语言范畴影响颜色知觉的机制.实验1让被试接受短期“色-词”重组训练,使原先范畴内的两种颜色变为范畴间的颜色,训练前后完成视觉搜索任务.反应时结果显示,在训练后,与训练的两种颜色近似的另外两种颜色的知觉表现出边缘显著的偏侧化颜色范畴效应.实验2让被试接受与实验1相同的训练后,完成视觉Oddball任务.ERP结果显示,在训练后,与训练的两种颜色近似的另外两种颜色的偏差刺激在早期知觉阶段就表现出偏侧化vMMN效应.这些结果表明:习得的语言范畴能影响早期的、注意前的颜色知觉机能,且这一影响过程可以在短期内完成;习得的语言范畴会影响颜色知觉范畴,而非仅影响特定颜色点的知觉机能.     

Investigating the Constrained Action Hypothesis: A Movement Coordination and Coordination Variability Approach

The purpose of this study was to examine the effects of focus of attention cues on movement coordination and coordination variability in the lower extremity. Twenty participants performed the standing long jump under both internal and external focus of attention conditions. A modified vector coding technique was used to evaluate the influence of attentional focus cues on lower extremity coordination patterns and coordination variability during the jumps. Participants jumped significantly further under an external focus of attention condition compared with an internal focus of attention condition (p = .035, effect size = .29). Focus of attention also influenced coordination between the ankle and knee, F(6, 19) = 2.87, p = .012, effect size = .388, with participants primarily using their knees under the internal focus of attention, and using both their ankles and knees under the external focus of attention. Attentional focus cues did not influence ankle-knee, F(1, 19) = 0.02, p = .98, effect size = .02, or hip-knee, F(1, 19) = 5.00, p = .49, effect size = .16, coordination variability. Results suggest that while attentional focus may not directly influence movement coordination condition, there is still a change in movement strategy resulting in greater jump distances following an external focus of attention.     

RECENT TRENDS IN THE COGNITIVE SCIENCE OF RELIGION: NEUROSCIENCE,RELIGIOUS EXPERIENCE,AND THE CONFLUENCE OF COGNITIVE AND EVOLUTIONARY RESEARCH

Cognitive science of religion (CSR) has increased influence in religious studies, the resistance of religious protectionists notwithstanding. CSR's most provocative work stresses the role of implicit cognition in explaining religious thought and conduct. Exhibiting explanatory pluralism, CSR seeks integrative accounts across the social, psychological, and brain sciences. CSR reflects prominent trends in the cognitive sciences generally. First, CSR is giving greater attention to the new tools and findings of cognitive neuroscience. Second, CSR researchers have done carefully designed, nonlaboratory studies of experience, incorporating precise physiological measures, obtaining astonishing findings about the experiences of ritual participants and observers. Third, CSR theorists have advanced evolutionary hypotheses about religions from eight perspectives (cross-indexing three levels of selection with three mechanisms of selection). Cultural group selectionists headline credibility enhancing displays and Big Gods in the religious consolidation of large-scale societies. Other CSR researchers marshal counterevidence and advance alternative hypotheses. CSR findings are incompatible with the New Atheists’ projects on two fronts.     

Does Agrammatic Speech Constitute a Regression to Child Language? A Three-Way Comparison between Agrammatic, Child, and Normal Ellipsis

When children are in the process of learning their mother tongue, they show frequent use of nonfinite clauses, even though they produce finite clauses at the same time, thereby demonstrating the availability of the functional domain associated with finiteness. In this study the hypothesis was tested that this behavior results from an overuse of the normal elliptical repertoire that has also been observed in agrammatic aphasia. The purpose of this overuse is prevention of computational overload. In support of the hypothesis it was found that children behaved very similar to aphasics and normal adults with respect to the following parameters: (a) distribution of types of ellipsis, (b) elaboration of ellipses, (c) word order, (d) subject omission, (e) frequency of weak subject pronouns, and (f) verb type (eventivity). The results also support the Jackson/Jakobson regression hypothesis, at least at the grammatical level.     

Plato's Hypothetical Inquiry in the Meno

This paper argues that the hypothesis proposed in the Meno is the proposition ‘virtue is good’ alone, and that its epistemic nature is essentially insecure. It has been an object of huge scholarly debate which other hypothesis Socrates posited with regard to the relationship between virtue and knowledge. This debate is, however, misleading in the sense of making us believe that the hypothesis that virtue is good is regarded as a truism in the light of the process of positing a higher hypothesis described in the Phaedo and the Republic. I argue that the hypothesis in question is presented as a result of the earlier discussion of Meno's third definition of virtue (77b2–79a2), which implies the consequence that morally correct actions are beneficial whether or not accompanied by conventional goods such as wealth and honour. The underlying role of presenting it as a hypothesis is therefore to postpone demonstrating the truth of a controversial thesis which needs a substantial justification. In conclusion, I suggest that Plato's real intention in introducing the method of hypothesis in the dialogue is not to answer the original question but to lead Meno to seek for knowledge.     

Characteristics of Unintentional Movements by a Multijoint Effector

The authors explored the phenomenon of unintentional changes in the equilibrium state of a multijoint effector produced by transient changes in the external force. The subjects performed a position-holding task against a constant force produced by a robot and were instructed not to intervene voluntarily with movements produced by changes in the robot force. The robot produced a smooth force increase leading to a hand movement, followed by a dwell time. Then, the force dropped to its initial value leading to hand movement toward the initial position, but the hand stopped short of the initial position. The undershoot magnitude increased linearly with the peak hand displacement and exponentially with dwell time (time constant of about 1 s). For long dwell times, the hand stopped at about half the total distance to the initial position. The authors interpret the results as consequences of a drift of the referent hand coordinate. Our results provide support for back-coupling between the referent and actual body configurations during multijoint actions and produce the first quantitative analysis of this phenomenon. This mechanism can also explain the phenomena of slacking and force drop after turning visual feedback off during accurate force production task.     

Control of Trajectory Modifications in Target-Directed Reaching

Human reaching movements to fixed and displaced visual targets were recorded and compared with simulated movements generated by using a two-joint arm model based on the equilibrium-point (EP) hypothesis (λ model) of motor control (Feldman, 1986). The aim was to investigate the form of central control signals underlying these movements. According to this hypothesis, movements result from changes in control variables that shift the equilibrium position (EP) of the arm. At any time, muscle activations and forces will depend on the difference between the arm's EP and its actual position and on the limb's velocity. In this article, we suggest that the direction of EP shift in reaching is specified at the hand level, whereas the rate of EP shift may be specified at the hand or joint level. A common mechanism underlying reaching to fixed and displaced targets is proposed whereby the EP of the hand shifts in a straight line toward the present target. After the target is displaced, the direction of the hand EP shift is modified toward the second target. The results suggest that the rate of shift of the hand EP may be modified for movements in different parts of the work space. The model, with control signals that vary in a simple fashion over time, is able to generate the kinematic patterns observed empirically.     

Choice and foraging

In Experiment 1, six naive pigeons were trained on a foraging schedule characterized by different states beginning with a search state in which completion of a fixed-interval on a white key led to a choice state. In the choice state the subject could, by appropriate responding on a fixed ratio of three, either accept or reject the schedule of reinforcement that was offered (either a variable-interval five-second or a variable-interval 20-second). If the subject accepted the schedule, it entered a “handling state” in which the appropriate variable-interval schedule was presented. Completion of the variable-interval schedule produced food. The independent variable was the fixed-interval value in the search state, and the dependent variable was the rate of acceptance of the long variable-interval in the choice state. Experiment 2 was identical except that the search state required completion of a variable-interval, instead of a fixed-interval, schedule. The rate of acceptance of the long variable-interval schedule in both experiments was a direct function of the length of the search state, in accordance with both optimality theory and the delay-reduction hypothesis.