Visual search for positional relationships between pattern elements

The purpose of these experiments was to illustrate how a search for positional relationships between the elements in a stimulus pattern is effortful and serial, whereas a search for pattern elements (without requiring any positional information) takes place rapidly and in parallel. In all three experiments of this study, the target and distractor patterns consisted of two vertical line segments. In the experiment concerning the search for positional relationships between pattern elements, one of the line segments in a line pair had a gap, and the observer's task was to indicate whether the positional order of the two lines was identical in all the line pairs of the display, or whether the line segments were in a mirror-image order in one line pair (the target). In the two experiments concerning the search for pattern elements (no positional information was required), the observer's task was to look for a line pair with one gap line (the target) among line pairs containing two broken lines or among line pairs with unbroken lines. In all three tasks, the reaction time for a correct target detection was measured. The results showed that the search in the first task was highly serial, and in the second and third tasks of "feature" searches, the search time was nearly independent of the number of distractor pairs. It is suggested that this dissociation may be interpreted in the context of the quality of information processing in extrafoveal vision, i. e. the elements of a stimulus pattern can be clearly visible outside the fovea, but it is not possible to perceive accurately the positional relationships between them.     

The pigeon's perception of saturation.

Three experiments used similar methods to investigate the pigeon's perception of saturation of monochromatic lights. This trial-wise procedure consisted of brief presentations of positive and negative stimuli in random sequence. Pecks to the positive stimuli were occasionally reinforced on a low fixed-ratio schedule. The first study determined absolute thresholds for "white" and monochromatic lights by establishing a discrimination between lights of various radiances and a dark key. Experiment II investigated generalization from a white light to various monochromatic lights under conditions that minimized the use of luminance as a cue. The third experiment examined discrimination of various monochromatic lights along a colorimetric purity continuum; responses to white light were reinforced, while responses to lights that combined white and monochromatic lights in various proportions were not. The results indicated that lights of different wavelength differ in saturation, but that all are discriminable from white. Wavelengths between 550 and 600 nm are least saturated for the pigeon, and saturation increases markedly as wavelength decreases below this region of the spectrum.     

Produire et réviser la morphologie flexionnelle du nombre : de l'accès à une expertise

To understand how children and adults produce written text, you must first be able to describe how they acquire some basic mechanisms. This is the reason to study the acquisition and use of simple orthographic principles. Following this idea, the research of Largy, Fayol et al. concerns nominal and verbal agreement in French. This article proposes a synthesis of the recent development in this domain. Through the study of two competences to be acquired by the writer — (1) to produce the flexional morphology of number in written text and (2) to revise and judge the correctness of this production — this article presents and discusses in which way the learner access to a writing expertise, always relative.     

The Epistemological Status of Vision and its Implications for Design

Computational theories of vision typically rely on the analysis of two aspects of human visual function: (1) object and shape recognition (2) co-calibration of sensory measurements. Both these approaches are usually based on an inverse-optics model, where visual perception is viewed as a process of inference from a 2D retinal projection to a 3D percept within a Euclidean space schema. This paradigm has had great success in certain areas of vision science, but has been relatively less successful in understanding perceptual representation, namely, the nature of the perceptual encoding. One of the drawbacks of inverse-optics approaches has been the difficulty in defining the constraints needed to make the inference computationally tractable (e.g. regularity assumptions, Bayesian priors, etc.). These constraints, thought to be learned assumptions about the nature of the physical and optical structures of the external world, have to be incorporated into any workable computational model in the inverse-optics paradigm. But inference models that employ an inverse optics plus structural assumptions approach inevitably result in a naïve realist theory of perceptual representation. Another drawback of inference models for theories of perceptual representation is their inability to explain central features of the visual experience. The one most evident in the process and visual understanding of design is the fact that some visual configurations appear, often spontaneously, as perceptually more coherent than others. The epistemological consequences of inferential approaches to vision indicate that they fail to capture enduring aspects of our visual experience. Therefore they may not be suited to a theory of perceptual representation, or useful for an understanding of the role of perception in the design process and product.     

Self‐generated variability in object images predicts vocabulary growth

Object names are a major component of early vocabularies and learning object names depends on being able to visually recognize objects in the world. However, the fundamental visual challenge of the moment‐to‐moment variations in object appearances that learners must resolve has received little attention in word learning research. Here we provide the first evidence that image‐level object variability matters and may be the link that connects infant object manipulation to vocabulary development. Using head‐mounted eye tracking, the present study objectively measured individual differences in the moment‐to‐moment variability of visual instances of the same object, from infants’ first‐person views. Infants who generated more variable visual object images through manual object manipulation at 15 months of age experienced greater vocabulary growth over the next six months. Elucidating infants’ everyday visual experiences with objects may constitute a crucial missing link in our understanding of the developmental trajectory of object name learning.     

Cathodal tDCS of the Left Posterior Parietal Cortex Increases Proprioceptive Drift

In aiming movements the limb position drifts away from the defined target after some trials without visual feedback, a phenomenon defined as proprioceptive drift (PD). There are no studies investigating the association between the posterior parietal cortex (PPC) and PD in aiming movements. Therefore, cathodal and sham transcranial direct current stimulation (tDCS) were applied to the left PPC concomitantly with the performance of movements with or without vision. Cathodal tDCS applied without vision produced a higher level of PD and higher rates of drift accumulation while it decreased peak velocity and maintained the number of error corrections, not affecting movement amplitude. The proprioceptive information seems to produce an effective reference to movement, but with PPC stimulation it causes a negative impact on position.     

Effects of a Rite of Passage Ceremony on Veterans' Well‐Being

Mixed methods were used to assess the impact of a Veterans Vision Fast program on 5 veterans' mental health. Posttraumatic stress disorder, depression, psychological flourishing, life satisfaction, and well‐being were measured twice before and twice after the program using a data collection app. Semistructured interviews assessed veterans' perceived experiences. The authors found significant overall changes and large effect sizes in each outcome over 6 weeks, and several themes emerged from the veterans' responses. The program positively affected veterans' lives.     

视知觉学习的认知与神经机制研究

知觉学习是指由于训练或经验而引起的长期稳定的知觉变化,是一种内隐性的学习。近20年来,视知觉学习的大量研究结果提示大脑皮层的各个区域,甚至包括初级感觉皮层,在成熟之后仍然具有一定的可塑性。该文根据近年来的研究进展,对视知觉学习在大脑的什么地方,什么时候,以何种方式发生等热点问题进行了探讨。研究提示,视知觉学习涉及了包括初级视皮层在内的多个大脑皮层,并且存在一种自上而下的调控机制;视知觉学习可以在不同的时间尺度上发生,快速学习之后将伴随着慢速学习;通过视知觉学习,人们对于复杂物体的表征将从高级皮层区域移向低级皮层区域,任务执行也将趋于自动化     

非球面人工晶状体临床应用的启示

非球面人工晶状体是波前像差技术与现代白内障手术完美结合的产物,也是多学科联合发展的结果。非球面人工晶状体较传统球面人工晶状体可明显改善白内障患者的视功能。倘若能实现个体化设计,非球面人工晶状体有望取代球面人工晶状体成为人工晶状体的主流。     

统计认知理论及应用研究

长期以来大家认为人类认知尽管可以看成是非确定的推理计算过程,但它的知识表达、模型结构、及计算方法和概率统计理论在本质上是不同的,因此认知科学和概率统计方法存在巨大的鸿沟,过去两者基本上独立发展。近年来随着Bayesian概率统计模型研究的一系列突破性工作和认知过程本质的不断被发现和挖掘,两者的相关性和互补性逐渐突显出来。许多研究者认为认知是近似遵循概率统计推理原则的,一些研究工作显示两者的结合有可能对人工智能发展产生深远的影响。本文对当前统计认知理论及应用研究的现状进行系统的梳理,并结合自身的研究对它今后的发展提出自己的看法。