The Linkage of Visual Motion Signals

Recovering a reliable 3D percept from the retinal sampling of dynamic images requires the linkage of motion signals across space and time. In this paper, we review recent experimental results that enhance our understanding of the perceptual processes of motion integration, segmentation, and selection that are necessary to solve this inverse optics problem. Simple paradigms involving the presentation of moving contours are used to assess our ability to link sparse motion information. Our results indicate that human motion perception strongly depends on both primitive stimulus characteristics, such as contrast, eccentricity, and duration, as well as higher level characteristics such as feature classification and spatial configurations. Further, the perceived direction of a moving object depends little upon its familiarity. Finally, pursuit eye movements of compositional stimuli are highly correlated with perceived motion coherence. This ensemble of results is analysed within the context of current theories of motion perception.     

视觉运动追踪的加工过程

视觉运动追踪是运动知觉研究的一个重要领域。通过构建视觉运动追踪的过程模型和分析每个阶段的认知加工任务, 可以帮助人们认识运动物体识别的本质。视觉运动追踪包括目标获取和运动追踪两个加工过程：目标获取阶段的主要任务是将目标与背景分离, 集中注意力加工追踪目标; 运动追踪阶段的主要任务是启动平滑追踪眼动和追赶性眼跳, 并发挥行为水平、眼动水平和神经活动水平的预测机制。目标获取同时受背景和目标的运动特征和身份特征影响; 运动追踪系统发挥预测机制的基础是客体表征连续性, 而客体表征连续性的建立同时依赖于目标时空属性和身份特征的编码加工。因此, 视觉运动追踪是视觉系统对客体运动信息和身份语义信息整合的结果。其中, 客体运动信息的加工特性已经获得了比较广泛的研究, 而语义信息加工机制还有待进一步加强。     

Apparent Distortions in Photography and the Geometry of Visual Space

In this paper I contrast the geometric structure of phenomenal visual space with that of photographic images. I argue that topologically both are two-dimensional and that both involve central projections of scenes being depicted. However, I also argue that the metric structures of the spaces differ inasmuch as two types of “apparent distortions”—marginal distortion in wide-angle photography and close-up distortions—which occur in photography do not occur in the corresponding visual experiences. In particular, I argue that the absence of marginal distortions in vision is evidence for a holistic metric of visual space that is spherical, and that the absence of close-up distortions shows that the local metric structure possesses a dynamic variable curvature which is dependent upon the distance away of objects being viewed at a given time.     

Momentary Happiness: The Role of Psychological Need Satisfaction

Psychological well-being correlates positively with psychological need satisfaction—primarily the needs of autonomy, competence, and relatedness. The current study explores momentary happiness (defined as experienced enjoyment minus experienced stress over the course of an hour) as a function of momentary psychological need satisfaction. Results demonstrate that hour-by-hour ratings of psychological need satisfaction were correlated with momentary happiness, with individual differences in life satisfaction moderating this relationship. Ratings of autonomy and relatedness correlated positively with momentary happiness, while competence was negatively correlated with momentary happiness. Thus, engagement in competence-promoting behaviors may come at an affective cost, at least in the moment. When autonomy and relatedness needs were met, individuals with high levels of life satisfaction experienced greater increases in happiness than individuals with low levels of life satisfaction. This finding supports a sensitization model of well-being. Results are discussed with respect to their implications for self-determination theory (SDT).     

客体运动方向的视觉工作记忆容量

记忆动态场景中多客体的特征和时空信息是人类重要的认知活动。目前有关视觉工作记忆的研究虽然广泛探讨了对视觉信息的存储容量及机制,然而所采用的刺激材料均呈现于静态场景中,且不包含运动信息。而有关多客体追踪的研究只关注动态场景中多客体信息的实时更新,而不涉及一段时间内对客体信息的保持。本研究结合视觉工作记忆领域的变化觉察范式和多客体追踪范式,以独立运动的客体为刺激材料,探讨多个客体的运动方向信息在工作记忆中的存储容量问题。结果表明,在工作记忆中能够存储大约3个客体的运动方向信息。     

Visual Illusions of Motion During Train Travel

Army Air Forces. Aviation Psychology Program Research Reports. Washington, D. C.: Goaernrnent Printing Ofice, 1947. Reviewed by H. J. Eysenck.     

Perceptual Grouping and Motion Coherence in Visual Search

Search for a conjunction of form and motion is greatly affected by manipulations of phase in the target and nontarget motion sets. To test whether this finding can be best explained by perceptual grouping, we moved a random set of dots in phase or counterphase with target or nontarget motion. Perceptual grouping was found to have a dramatic effect on search performance. We propose that this interaction between perceptual grouping and visual search is governed by three general rules. Our data also provide convincing evidence of the preattentive organization of a visual display into surfaces defined by common motion.     

Actions in Slow Motion: Theoretical and Methodological Reflections on Temporality in Actions and Intersubjective Understanding

This article examines the connection between actions, temporality, and media-based observation. Slow motion technology is currently being used especially in sports to examine and evaluate athletes’ actions more precisely in order to identify potential infringements of rules. Starting with a phenomenological perspective, this article engages in a critical assessment of the degree to which the intentions underlying athletes’ actions become clearer if their actions are slowed down using slow motion. It transpires that a more in-depth understanding is not possible because the process of time-stretching using media technology tends to obscure intersubjective understanding. Nevertheless, the use of different playback speeds does increase observers’ sensitivity to the temporality of action and observation. This is particularly the case when greater emphasis is placed on the body and its role in the formation and carrying out of intentions. With the phenomenological view and in special consideration of the body and the subjective intentionality, the paper contributes to a discussion about the connection of time and (inter-)action already led in ethnomethodology and conversation analysis. These findings mark a contribution to empirical social research as well, which is increasingly using video material in action analysis and should take slow motion as a possible augmented but also manipulated access to actions into account adequately. To this end, this article suggests a method for identifying the merits and demerits of using slow motion to analyse actions, and discusses the methodological implications of temporality in observation.

     

客体运动方向的视觉工作记忆存储方式

采用变化觉察范式,以独立运动的客体为对象,通过两个实验,探讨多个客体的运动方向在视觉工作记忆中的存储机制,即单个对象独立存储,抑或其存储受多个客体构型的影响。实验一和实验二相继考察了非目标客体运动方向变化,以及是否存在非目标客体对觉察目标客体运动方向的影响。结果发现,非目标客体运动方向变化条件下的觉察正确率显著低于不变的条件,然而只呈现目标客体条件下的觉察正确率与同时呈现目标和非目标条件无显著差异。该结果与前人在静态条件下对目标客体的觉察受目标客体和非目标客体整体构型影响的结论不一致。本研究的结果支持多个客体的运动方向信息在工作记忆中是以独立方式存储的假设。     

运动视觉中计时行为的控制操作理论

运动视觉中的计时行为分为两类 :拦截行为和制动行为。“环境—活动者系统”(EAS)中的信息决定着计量行为的控制操作。本文阐明了信息和EAS的特性 ,通过对 tau-margin在拦截行为中的作用以及视觉变量τ对于制动操作重要性的分析 ,论述了运动视觉中计时行为的控制操作理论。     

The Role of Visual Feedback about Motion of the Ground on Postural Sway

Abstract

We asked whether body sway would be influenced by visual information about motion of the ground surface. On a ship at sea, standing participants performed a demanding visual search task or a simple visual inspection task. Display content was stationary relative to the ship or relative to the Earth. Participants faced the ship’s bow or its port side. Performance on the visual search task was representative of terrestrial studies. Body sway was greater during viewing of the Earth Stationary displays than during viewing of the Ship Stationary displays. We discuss possible implications of these results for theoretical and applied issues.     

Slow Motor Responses to Visual Stimuli of Low Salience in Autism

ABSTRACT

The authors studied 2 tasks that placed differing demands on detecting relevant visual information and generating appropriate gaze shifts in adults and children with and without autism. In Experiment 1, participants fixated a cross and needed to make large gaze shifts, but researchers provided explicit instructions about shifting. Children with autism were indistinguishable from comparison groups in this top-down task. In Experiment 2 (bottom-up), a fixation cross remained or was removed prior to the presentation of a peripheral target of low visual salience. In this gap–effect experiment, children with autism showed lengthened reaction times overall but no specific deficit in overlap trials. The results show evidence of a general deficit in manual responses to visual stimuli of low salience and no evidence of a deficit in top-down attention shifting. Older children with autism appeared able to generate appropriate motor responses, but stimulus-driven visual attention seemed impaired.     

The Limits of Photography

Abstract

This paper is about what counts as a photograph and what does not. One way in which this question arises stems from new technologies that keep changing our way of producing photographs, such as digital photography, which not only has now widely replaced traditional film photography but also challenges the very limits of what we count as a photograph. I shall discuss below at some length different aspects of digital photography, but also want to focus here on a new striking type of photographic camera, announced in early 2012 by Lytro, Inc., namely, the so-called ‘Light Field Camera’, which is said to represent a revolution in the photographic world. Indeed, unlike in the case of any previously available cameras, the photographs produced by a Light Field Camera can be re-focused after the photograph has been taken, which harbours many interesting consequences with regard to the resulting image and the way we interact with it. But of course, the initial question also arises in the case of traditional film photography as well as ‘traditional’ digital photography. The question amounts to asking about what the essential features of photographs are – in short, what their nature is.     

Neural Correlates of Age-related Reduction in Visual Motion Priming

ABSTRACT

Previously we reported that priming of visual motion perception is reduced in older adults compared to younger adults (Jiang, Greenwood, & Parasuraman, 1999 Jiang, Y., Greenwood, P. and Parasuraman, R. 1999. Age-related reduction in 3-D motion priming. Psychology and Aging, 14(4): 619–626.  [Google Scholar], Psychology and Aging, 14(4), 619; Jiang, Luo, & Parasuraman, 2002b Jiang, Y., Luo, Y. J. and Parasuraman, R. 2002b. Two-dimensional visual motion priming is reduced in older adults. Neuropsychology, 16(2): 140–145.  [Google Scholar], Neuropsychology, 16(2), 140). To examine the neural mechanisms underlying this age-related effect, event-related brain potentials (ERPs) were recorded during perceptual judgments of motion directions by younger and older adults in two experiments. When judging single-step motion, both younger and older adults evoked significantly larger ERP late positive component (LPC) responses to unambiguous motion compared to LPC responses elicited by ambiguous motion. In contrast, compared to the younger adults, the older adults evoked comparable but delayed ERP responses to single motion steps. In the second experiment the younger and older groups judged the directions of two successive motion-steps (either motion priming or motion reversals). Under short (200–400 ms) stimulus onset asynchrony (SOA), the difference between the ERP responses to priming and reversal conditions was significantly larger for the younger than for the older adults. This study provides the first electrophysiological evidence that brain aging leads to delayed processing of single motion direction and visual motion priming as early as 100 ms in the early visual cortex. Age-related changes in strength and temporal characteristics of neural responses in temporal-parietal regions were particularly pronounced in older adults when successive motion signals are placed closely in time, within 400 ms.     

Visual Feedback in Written Imaginal Exposure for Posttraumatic Stress: A Preliminary Study

This study investigated the visual feedback hypothesis, which states that visual feedback from written trauma narratives contributes to the efficacy of written imaginal exposure for posttraumatic stress via the reuptake of traumatic content during production of the narrative. We tested a college sample (n = 61) with clinically elevated posttraumatic stress as measured with the Impact of Events Scale. Participants were randomly assigned to a writing with visual feedback condition, a writing without visual feedback condition, or a control condition. The hypothesis was not supported: Writing with and without visual feedback equally reduced intrusion and avoidance symptoms. Exploratory analyses, however, showed increased intrusion symptoms immediately after writing with visual feedback, which was in contrast with decreased symptom levels in the other conditions. These findings are in line with previous findings regarding immediate symptom development following writing interventions for posttraumatic stress and call for further exploration of the visual feedback hypothesis.