Awareness in the crowd: Beta power and alpha phase of prestimulus oscillations predict object discrimination in visual crowding

Visual crowding is among the factors that most hamper conscious object perception. However, we currently ignore the neural states that predispose to an accurate perception within different crowding regimes. Here, we performed single-trial analyses of the electroencephalographical (EEG) oscillations, evaluating the prestimulus power and phase differences between correct and incorrect discrimination during a letter-crowding task, where irrelevant letters were placed nearby (strong crowding) or far (mid crowding) relative to the target. Results show that prestimulus alpha (8–12 Hz) power was related to target discrimination in the mid, but not in the strong, crowding condition. Importantly, accurate discrimination in the strong crowding condition was predicted by the phase of alpha and by the power of beta (13–20 Hz) oscillations. These evidence suggest that both periodic visual sampling mechanisms, reflected in the alpha phase, and network predisposition to extract local information, reflected in the beta power, predispose to object discrimination in a crowded scene.     

Computational Cognitive Neuroscience of the Visual System

ABSTRACT— Should psychologists care about functional magnetic resonance imaging (fMRI)? Within the field of visual perception, the answer to this question is an emphatic "yes." There is a long history of close interactions between psychology and neuroscience in the study of vision. In the 1980s, vision researchers developed a general framework for combining the two fields, and that framework still supports much current research. This article will briefly cover this general approach and then will illustrate how neuroimaging allows the framework to be applied to human perception. In short, fMRI can measure how information is represented in sequential stages of processing. These same representations can also be measured behaviorally. Theories of vision specify how the sequential representations participate in well-defined computations that underlie perception.     

Visions of Brazilian Scientists on Nanosciences and Nanotechnologies

This article examines the visions on nanosciences and nanotechnologies (N&N) disseminated by a group of Brazilian scientists to legitimize this emergent field of research. For this purpose we analyzed reports on N&N published by the Journal of Science, edited daily by the Brazilian Society for the Progress of Science, from 2002 to 2007, covering the period in which the main events in domestic N&N research policy took place. Our analysis shows that researchers on N&N are spreading visions of progress, efficiency and competitiveness related to the advances in this field, giving little attention to issues such as potential risks, and economic, social and ethical implications of these technologies.

大学生生命愿景、自我效能感与应对方式的关系

采用问卷法以377名大学生为被试研究了生命愿景、一般自我效能感及应对方式的关系。研究结果为:1)大学生生命愿景整体水平较高,存在着性别和年级差异,女生的生命愿景显著高于男生;大一学生显著高于大四;2)生命愿景不同水平的大学生在一般自我效能感上存在显著性差异(t=7.35,p<0.001);在积极应对与消极应对因子上有显著性差异。3)大学生生命愿景与一般自我效能感呈显著正相关,并对自我效能感具有良好的预测作用;4)大学生生命愿景与积极应对方式呈显著正相关,与消极应对方式呈显著负相关;5)大学生生命愿景通过一般自我效能感对应对方式产生间接影响。结论为生命愿景作为应对源对大学生应对校园压力发挥积极作用。     

Development of chromatic induction in infancy

The perception of colour in an embedded field is affected by the surround colour. This phenomenon is known as chromatic induction. In the present study we investigated whether the colour perception by infants aged 5–7 months could be affected by the surround colour. In Experiments 1 and 2 each stimulus was composed of an array of six squares in tandem. The colour appearance of the array in the familiarization stimulus was established by chromatic induction. In Experiment 1 we used familiarization stimuli that were perceived as two‐colour array with a two‐colour surround. In Experiment 2 we used a familiarization stimulus that was perceived as a uniform‐colour array with a two‐colour surround. In the test phase, the uniform‐colour array and the two‐colour array were presented on a white uniform‐colour surround in both experiments. The results showed that in Experiment 1 the 5‐ and 7‐month‐old infants had novelty preference for the uniform‐colour test array. This suggested that the infants' colour perception could be affected by surround colour. The results of Experiment 2 showed that the 7‐month‐olds showed a novelty preference for the two‐colour test array, but the 5‐month‐olds showed no novelty preference. This suggested that 7‐month‐olds' colour perception could be affected by surround colour, but that of 5‐month‐olds could not. We discuss the contradiction of the results between Experiments 1 and 2. Copyright © 2007 John Wiley & Sons, Ltd.     

视觉工作记忆中的特征捆绑

特征捆绑是认知科学和神经科学研究的前沿问题,近来已经成为研究者们关于意识问题争论的焦点所在。很多心理活动涉及复杂对象各种特征的捆绑,在工作记忆中保持这些捆绑的机制是心理加工得以有效进行的基础。视觉工作记忆中的特征捆绑近来成为研究热点之一,有关研究大多凭借变化检测范式和单刺激探测范式,探讨了视觉工作记忆中捆绑特征的保持是否需要注意参与,以及分离特征存储和捆绑特征存储的关系等问题,但目前这些问题仍都没有明确的答案。     

理解心理学:历史形态、特征与评析

理解心理学是一种坚持心理学的人文科学取向,倡导人特有研究方式的建构与运用,以达成对人及其心理生活本质或生命意义与价值的理解、描述为目标的心理学流派、思想主张或形态。其发展先后呈现出知识论取向的理解心理学、价值论(或生存论)取向的理解心理学、整合论取向的理解心理学。在方法论上具有鲜明的人文主义特征,致力于探究人的社会本性,构筑了人文科学心理学的历史样态。未来,理解心理学还需摒弃非此即彼的思维方式,携手说明心理学共同推动心理学走向成熟     

How visually impaired cyclists ride regular and pedal electric bicycles

The present study investigates whether visually impaired cyclists compensate for their vision limitations by maintaining a lower speed or a larger distance to the kerb than normally sighted cyclists when riding a regular bicycle or pedal electric bicycle (pedelec). A normally sighted control group (n = 10), a peripheral visual field loss group (n = 9), and a low visual acuity group (n = 12) rode a fixed route (7.5 km) in the Netherlands on a regular bicycle and on a pedelec. Speed and lateral position were measured when participants cycled a (I) one-way cycle path, (II) two-way cycle path, (III) residential area, and (IV) shared space zone. With regard to both the regular bicycle and the pedelec, no significant speed or lateral position differences were found between the three groups. In conclusion, for some people with severe and permanent visual impairments, and under certain circumstances, regular bicycle and pedelec riding may be possible without noticeable speed reduction or adapted lane position to compensate for their functional impairment. The present findings may further optimise the cycling advice provided by mobility trainers of vision rehabilitation centres and the independent mobility of visually impaired people.     

Integration of Intermittent Visual Samples Over Time and Between the Eyes

The authors investigated the integration of alternate disparate monocular inputs for binocular perception in 1-handed catching experiments (N = 14, 32, 22, and 15 participants, respectively in Experiments 1-4). They varied the no-vision interval between alternate monocular samples to measure catching performance, and they compared the alternating monocular conditions with binocular and monocular conditions with equal no-vision intervals. They found no evidence of a binocular advantage for one-handed catching in the alternating monocular conditions. Performance in monocular and alternating monocular conditions did not differ across no-vision intervals ranging from 0-80 ms and was particularly worse than performance in binocular viewing conditions when the no-vision interval was 40 ms or more. The authors argue that the dissimilarity between disparate monocular inputs created by the approaching object limited the integration of those inputs and subsequent binocular perception.