Periphery Of Vision Research Articles

Properties of pursuit movements.

This chapter describes dynamic properties of smooth pursuit, visual and non-visual stimuli for pursuit, smooth eye-head tracking movements, and plastic-adaptive properties of pursuit. Step-ramp visual stimulus motion has revealed important properties of pursuit, including the latency to onset, initial acceleration, accuracy, and transient oscillations-all features that have been used to develop models of the pursuit system, discussed in the chapter "Models of pursuit" by Robinson. The role of predictive neural mechanisms in generating pursuit movements that anticipate target motion, and that enable near-perfect tracking of sinusoidal target motion, are examined. Smooth pursuit can be generated in response to targets that do not move, such as stroboscopic lights and images stabilized in the periphery of vision. The view that, during combined eye-head pursuit, the pursuit signal is used to cancel the vestibulo-ocular reflex is an incomplete hypothesis, contradicted by behavioral and electrophysiological findings. Smooth pursuit shows adaptive capabilities, evident in individuals who develop extraocular muscle palsies.

Inattention blindness in surgery.

Inattention blindness (IB) can be defined as the failure to perceive an unexpected object when attention is focussed on another object or task. The principal aim of this study was to determine the effect of cognitive load and surgical image guidance on operative IB. Using a randomised control study design, participants were allocated to a high or low cognitive load group and subsequently to one of three augmented reality (AR) image guidance groups (no guidance, wireframe overlay and solid overlay). Randomised participants watched a segment of video from a robotic partial nephrectomy. Those in the high cognitive load groups were asked to keep a count of instrument movements, while those in the low cognitive load groups were only asked to watch the video. Two foreign bodies were visible within the operative scene: a swab, within the periphery of vision; and a suture, in the centre of the operative scene. Once the participants had finished watching the video, they were asked to report whether they had observed a swab or suture. The overall level of prompted inattention blindness was 74 and 10% for the swab and suture, respectively. Significantly higher levels of IB for the swab were seen in the high versus the low cognitive load groups, but not for the suture (8 vs. 47%, p<0.001 and 90 vs. 91%, p=1.000, for swab and suture, respectively). No significant difference was seen between image guidance groups for attention of the swab or suture (29 vs. 20%, p=0.520 and 22 vs. 22%, p=1.000, respectively). The overall effect of IB on operative practice appeared to be significant, within the context of this study. When examining for the effects of AR image guidance and cognitive load on IB, only the latter was found to have significance.

Eye movement control.

is well-known that eye movements are central to visual perception [1]. Visual acuity decreases dramatically in the periphery of vision, and precise eye movements to specific locations are vital to foveate objects of interest and identify them with high accuracy [1–4]. Given the importance of eye movements for visual perception, there has been a surge of interest in the topic, with numerous studies being conducted to clarify the variables that determine our eye movements (for a historical review see [5]). In fact, Google Scholar shows that eye movements are discussed in over a million publications, and a Web of Science search reveals 17,000 publications with eye movement in the title or abstract. As shown in Figure 1, the number of publications with eye movement in the title or abstract has also steadily increased over years, culminating in about 200 papers published in 2013. Figure 1 The number of publications with the “eye movement” in the title or abstract, according to a Web of Science search 2014. Despite the surge of interest in eye movements, many questions remain unresolved. This is also reflected in this special issue on eye movement control. First, there are a variety of different eye movements [2, 4]. Among the most widely known eye movements are the fast, ballistic saccades (including superfast express saccades) (e.g., B. de Gelder et al., this issue), smooth-pursuit eye movements (J. N. van der Geest et al., this issue), and vergence eye movements (e.g., P. M. Grove et al., this issue) required to fixate objects at different depths. Less well-known and yet intensely researched are microsaccades, tremor, slow drift, and vestibuloocular and optokinetic eye movements that stabilize gaze during motions of the head and motions of large regions of the image on the retina [2, 4]. Secondly and more importantly for the current special issue, eye movements are also controlled by a variety of different factors [1, 4]. Apart from being subject to diverse muscular and ocular constraints, successful voluntary control over eye movements critically depends on the quality of the visual input, which in turn depends on a variety of internal and external factors [1, 6, 7]. The contributions to the present special issue clarify key elements of both internal and external factors in eye movement control (G. W. Alpers et al., U. Ansorge et al., B. de Gelder et al., P. M. Grove et al., D. R. Hardwick et al., W. E. Huddlestone et al., J. Kassubek et al., A. Khan et al., A. Piras et al., N. D. Smith et al., J. N. van der Geest et al., and D. Venini et al., this issue). In the present contributions, eye movements have also been used to provide new insights into ocular and neurological disorders (J. Kassubek et al., N. D. Smith et al., this issue) and shed new light on the relationship between covert attention and eye movements (e.g., G. W. Alpers et al., U. Ansorge et al., D. R. Hardwick et al., and A. Khan et al., this issue; see also [6–9]). Together, the papers in this special issue provide a timely update on eye movement control that reflects current hot topics in the field, spanning the range from cognitive science over applied psychology to clinical psychology and neuroscience. Stefanie I. Becker Gernot Horstmann Arvid Herwig

I Agree: Binocular Rivalry Stimuli are Common but Rivalry is Not

I Agree: Binocular Rivalry Stimuli are Common but Rivalry is Not

Eyes Gaze Cueing Effect: Endogenous or Exogenous Processing Mechanism?

Observing another person's averted eye gaze led to automatic shift of attention in the corresponding direction,which facilitated subsequent early visual processing. This phenomenon was termed 'eyes gaze cueing effect',in short,'gaze cueing effect' (GCE). Many researchers tried to interpret the processing mechanism underlying GCE. However,there were controversies on this topic. Friesen and Kingstone (2003) claimed that gaze cues triggered a kind of reflexive or exogenous shift of visual attention that was normally associated with the abrupt onset of a stimulus in the periphery of vision. Whereas Vecera and Rizzo (2004) found a patient EVR with frontal-lobe damage was impaired in using eye gaze cues to allocate attention,suggesting that GCE may involve frontal-lobe processes which control voluntary,not automatic,shifts of visuospatial attention. Both viewpoints have gained some evidences. Thus,whether gaze cues shifted spatial attention reflexively (exogenously) or voluntarily (endogenously) was still in debate. This issue would be clarified in the present study in two aspects. On the one hand,how gaze cues shifted observer's attention. On the other hand,how gaze cues affected the processing of the target in the corresponding direction. Two experiments were conducted in this study,which employed the spatial Stroop paradigm and the target search task respectively. In both experiments,subjects were presented with a gaze cue to the right or left visual field (VF) before the occurrence of a lateralized target to response. There were two conditions in this non-predictive cueing task:(1) targets were presented in the VF indicated by the eye gaze direction (congruent); or (2) targets were opposite to the eye gaze direction (incongruent). In the first experiment,22 subjects were required to discriminate the direction to which the peripherally presented arrow points. While in the second experiment,another 16 subjects all were instructed to finish two different tasks:One involved the detection of single feature,and the other involved the search of feature conjunction. Stimulus presentation and data collection were conducted by E-prime software. From the first experiment,it was found:(1) The lack of GCE was due to the processing conflict between gaze cue and other endogenous cues,which indicated that the two cues had similar processing mechanism; (2) Gaze cue produced larger spatial Stroop effects for valid than invalid trials,which suggested that eyes gaze led to the generation of an internal representation of the spatial location. From the second experiment,similar facilitation effects of the gaze cue for both single feature and feature conjunction search was found,which revealed that gaze cue affected feature extraction as well as later processing stages (decision and response processes),but it did not influence feature integration directly. It was concluded that the intrinsic mechanism of GCE belonged to the endogenous attention system. Eyes gaze cue may induce observers' attention shift through the generation of an internal representation of the spatial location indicated by the cue,and facilitate target feature extraction and encoding,thus speed up the response ultimately.

The Task of the Name: A Reply to Carol Poster

One of the first things learned in the most rudimentary attempt at stargazing is that the utmost effort must be paid in neglecting to gaze at stars. Instead, one must gaze near them. Owing to the physiological organization of the eye, night vision is enhanced toward the periphery of vision rather than the center. Consequently, one can actually perceive one's own lack of perception by staring at a star, finding it disappear, and then staring near the star only to see it reappear. What follows, in this light or darkness or tension of these two extremes, is not empirical in any sense of the word, which is given to its own extremes. Rather, I hope through various a/(i)llusions and sidelong tangents to glance off the surface of my target. As you may guess, superficial puns?like star(e)?provide one of the most reflective surfaces off of which to bounce/riff.

Representing the Homeless

task of representing homelessness in America is a complex one. In each case, whether the medium of communication is the photographic essay, the statistical analysis, the case study, or the documentary film, an effort is made to demonstrate the seriousness of the crisis of homelessness, to explain its origins and development, and to foster the political will necessary to effect long-term solutions. These works all tend to depict the experience of being homeless through the story of particular individuals, yet there is considerable variation in their portrayals. In these views the homeless range from exhausted, troubled, and dispossessed people deserving of our sympathy and care to intelligent, socially aware, self-critical agents asserting and fighting for their rights and dignity. The way these texts, photographs, and films represent homelessness finally effects a kind of reversal, allowing us to become aware of the complex discourse of charity that pervades our way of perceiving social relations and our attempts to accomplish political change. Jim Hubbard's photographs of the homeless in American Refugees bring what is usually at the periphery of vision to the center of attention. A young woman sunk down on a plastic milk crate on a bustling sidewalk holding her baby seems confused, imploring, and helpless. A ragged man with an overgrown beard and a dirty blanket clutched across his shoulders strides across a city park. At first view he appears half crazed. Bundled up against the cold, old men hunch outside a public building. A family turned out of their apartment huddles with mattresses and scant possessions. They seem grief-stricken, lost, and beaten. Passersby appear to gawk at recumbent lumpish bundles coated in snow. Hugging his chest, a young black boy stands by while his family is evicted. His stare conveys a concentrated, silent anger. Hubbard's pictures remind us of news accounts and television clips, and of scenes many of us witness every day. While each photograph is an isolated image, in their accumuAmerican Refugees By Jim Hubbard University of Minnesota Press, 1991

The effects of the reader's skill and the difficulty of the text on the perceptual span in reading.

Development of the perceptual span in reading was investigated by varying the availability of graphic information in the periphery of vision. Low-ability eighth-grade readers, high-ability eighth-grade readers, and skilled adult readers read texts presented in a normal prose format, with a single space between words, and texts typed with 13 letter spaces between words. It was found that removing peripheral information by wide spacing improved comprehension for low-ability eighth graders but did not affect their overall reading efficiency (the number of questions answered correctly per minute of reading time). Wide spacing decreased the reading efficiency of high-ability eighth-grade readers and skilled adult readers. In addition, the texts were of two levels of difficulty. It was hypothesized that subjects would employ a larger span of perception with the easy text. Surprisingly, the wide spacing of words did not produce greater decrement fo reading efficiency with the easy text. The findings thus suggest that the perceptual span may increase as reading skill develops but does not change under the influence of momentary task variables.

Comments on W. A. Adams' Analysis of J. M. Kennedy's Seven Features of Pictures

John M. Kennedy has listed seven features of pictures that are not found in non-pictorial objects. He claims that viewers must develop a special skill before they can interpret these features [1]. William A. Adams has critically analyzed the features [2], but I believe his analyses are faulty, as I shall indicate below. The features are considered in the order found in Kennedy's and in Adams' article. 1. Kennedy stated that pictures are flat surfaces that depict things other than themselves and that viewers must be able to hold the flatness of a picture's surface in abeyance and treat the information for the pictured world somewhat separately. Adams takes this to mean that viewers must disregard the flatness of a picture's surface. Surely, 'to treat. . . somewhat separately' does not mean to disregard! 2. Kennedy stated that the flatness information must not be forgotten entirely or one will suffer trompe l'oeil and possibly be unable to compensate for viewing a picture from incorrect viewpoints, because one will not be able to recognize that one is examining a depicted scene via a canvas at a particular location (see also point 6 below). Adams recasts the statement to read: 'The disregard must not be total, else the picture would be mistaken for a window.' This is correct. However, Adams then says: 'There is no danger that pictures will be mistaken for real scenes, unless they are viewed monocularly from a fixed position.' This is not correct, for, although it is true that binocular vision allows one to distinguish more accurately between a real object and a picture of it in most cases, it has been shown by Kennedy and Magee [3] that, even with binocular viewing and physically unrestricted viewpoints trompe l'oeil can occur. This was demonstrated by showing to a few persons an outline drawing of four children facing an open central design and a pencil above them to the right (Fig. 1). When directed to look at the picture and to complete it by drawing something in the open central design, the persons, after gazing at the picture for a while, on occasion would reach for the depicted pencil! A trompe l'oeil effect like this was probably due to the fact that the depicted pencil was at the person's periphery of vision while attention was concentrated on the central part of the picture, as directed. If instead of a pencil an object cognitively irrelevant to the task had been depicted, the trompe l'oeil effect probably would not have been produced.

Some effects of infrasound on task performance

Some effects of moderate levels of infrasound on the performance of a complex task have been investigated using two experimental designs. A comparison between these effects and those due to alcohol, audio frequency noise, and combinations of infrasound-alcohol and alcohol-audio frequency noise is also presented. The complex task adopted for these experiments consisted of (a) a centrally located high priority pointer following task which had to be performed continuously and (b) the response to the onset of any one of four lights two of which were situated in front of the subject and two on his periphery of vision. The task was performed over a period of 36 minutes. Our results indicate that although performance in the infrasound condition does not suffer significant decrements in either the primary task or the central and peripheral components of the secondary task, the effects through time, both within the infrasound condition and in relation to the control, produce changes which are of a different nature to those of audible noise. In audible noise performance is maintained through time, whereas with infrasound and alcohol it appears to be degraded.

The effect of alcohol and noise on components of a tracking and monitoring task.

Recent findings in stress research indicate the necessity for examining the distribution of the operator's attention in complex tasks as well as his information transmission capabilities. This study examines the effects of alcohol and noise on a complex tracking and signal‐detection task with particular reference to changes in selective attention. The operator was instructed to give the tracking task priority. In noise tracking performance improved, but detection of lights placed on the periphery of vision was degraded. Alcohol had the same effect on peripheral detection, but tracking performance fell. It was concluded that the effect of alcohol on such simulated driving skills embodied two factors: the first an increase in attentional bias towards the high priority regions of the visual field, and the second a decrease in the information transmission rate. Since from the point of view of the tracking task these factors are mutually antagonistic, there may be an offsetting of the loss in transmission rate by more optimal dispositions of attention. The loss of peripheral awareness in this event is inevitable, and even at the low alcohol levels used was of apparently serious proportions.

Induced autokinesis

The egocentric location of a fixated visual stimulus was shifted away from the apparent median plane through induced movement. When the stimulus appeared to lie in the periphery of vision, the inducing frame was occluded resulting in autokinesis toward the phenomenally straight-ahead position. This effect was termed “induced autokinesis.” It was used in demonstrating that apparent egocentric displacement is sufficient for initiating autokinesis.