An application driven comparison of depth perception on desktop 3D displays.

Desktop 3D displays vary in their optical design and this results in a significant variation in the way in which stereo images are physically displayed on different 3D displays. When precise depth judgements need to be made these differences may become critical to task performance. Applications where this is a particular issue include medical imaging, geoscience and scientific visualization. We investigate perceived depth thresholds for four classes of desktop 3D display; full resolution, row interleaved, column interleaved and colour-column interleaved. Given the same input image resolution we calculate the physical view resolution for each class of display to geometrically predict its minimum perceived depth threshold. To verify our geometric predictions we present the design of a task where viewers are required to judge which of two neighboring squares lies in front of the other. We report results from a trial using this task where participants are randomly asked to judge whether they can perceive one of four levels of image disparity (0,2,4 and 6 pixels) on seven different desktop 3D displays. The results show a strong effect and the task produces reliable results that are sensitive to display differences. However, we conclude that depth judgement performance cannot always be predicted from display geometry alone. Other system factors, including software drivers, electronic interfaces, and individual participant differences must also be considered when choosing a 3D display to make critical depth judgements

The effect of high- and low-frequency previews and sentential fit on word skipping during reading

In a previous gaze-contingent boundary experiment, Angele and Rayner (2013) found that readers are likely to skip a word that appears to be the definite article the even when syntactic constraints do not allow for articles to occur in that position. In the present study, we investigated whether the word frequency of the preview of a 3-letter target word influences a reader’s decision to fixate or skip that word. We found that the word frequency rather than the felicitousness (syntactic fit) of the preview affected how often the upcoming word was skipped. These results indicate that visual information about the upcoming word trumps information from the sentence context when it comes to making a skipping decision. Skipping parafoveal instances of the therefore may simply be an extreme case of skipping high-frequency words

Fixation disparity during reading: Fusion, not suppression

In this paper I present a brief review of some recent studies my colleagues and I have carried out to investigate binocular coordination during reading. These studies demonstrate that the eyes are often not perfectly aligned during reading, with fixation disparities of approximately one character on average. Both crossed and uncrossed disparities are common and vergence movements during fixations serve to reduce, but not eliminate disparity. Fixation disparity results in different retinal inputs from each eye, yet a single non diplopic visual representation of the text is perceived when we read. A further experiment, with dichoptically presented target words in normally presented sentence frames, showed that a mechanism of fusion rather than suppression operates at an early stage during visual processing. Saccade metrics appear to be computed according to a unified visual representation based on input from both eyes. based on input from both eyes

Coaching Knowledge and Noticing in Youth Sports: Challenging the Assumption of Expertise

Sport is an integral part of the majority of children\u27s lives. Participation in sport can provide children with many physical and psychological benefits. Tasked with coaching children are coaches who are often parents and volunteers. These coaches have a variety of different levels of experience and expertise. A question that must be answered is what are the range of kinds of knowledge that coaches rely upon? This study delves further and attempts to understand how coaches use this knowledge in the act of noticing. Alongside understanding the complexity of coaching this study attempts to demonstrate the individuality and diversity in coaching and how subjective perceptions of a coaching session can be.;The participants in this qualitative study consisted of four novice, four intermediate, and four expert soccer coaches. A multi-layered interview served as the central data collection tool. Coaches watched a 10-minute video and then participated in an unstructured interview followed by a semi-structured interview. The semi-structured interview was guided by notes taken by the interviewer during the unstructured interview.;An inductive content analysis was employed to allow identification of patterns or themes that emerge from the collected data. A three-phase analysis was used: (a) data reduction, (b) data display, and (c) conclusion drawing and verification (Miles & Huberman, 1994). A constant comparative method (Glaser & Strauss, 1967) was utilized during the data analysis process to evaluate whether the coded sections of transcribed text were consistent and ensured they belong in their themes and subthemes.;The findings of this study provide domains of knowledge that coaches noticing during a coaching session. Coaches within this noticed with varying degrees of complexity and depth. This study provided insight into nine new areas of knowledge that coaches notice during a coaching session. The complexities and subjective nature of coach noticing are demonstrated through the findings of this study

Change blindness and the primacy of object appearance

A large body of work suggests that the visual system is particularly sensitive to the appearance of new objects. This is based partly on evidence from visual search studies showing that onsets capture attention whereas many other types of visual event do not. Recently, however, the notion that object onset has a special status in visual attention has been challenged. For instance, an object that looms toward an observer has also been shown to capture attention. In two experiments, we investigated whether onset receives processing priority over looming. Observers performed a change detection task in which one of the display objects either loomed or receded, or a new object appeared. Results showed that looming objects were more resistant to change blindness than receding objects. Crucially, however, the appearance of a new object was less susceptible to change blindness than both looming and receding. We argue that the visual system is particularly sensitive to object onsets

Investigating eye movement acquisition and analysis technologies as a causal factor in differential prevalence of crossed and uncrossed fixation disparity during reading and dot scanning

Previous studies examining binocular coordination during reading have reported conflicting results in terms of the nature of disparity (e.g. Kliegl, Nuthmann, &amp; Engbert (Journal of Experimental Psychology General 135:12-35, 2006); Liversedge, White, Findlay, &amp; Rayner (Vision Research 46:2363-2374, 2006). One potential cause of this inconsistency is differences in acquisition devices and associated analysis technologies. We tested this by directly comparing binocular eye movement recordings made using SR Research EyeLink 1000 and the Fourward Technologies Inc. DPI binocular eye-tracking systems. Participants read sentences or scanned horizontal rows of dot strings; for each participant, half the data were recorded with the EyeLink, and the other half with the DPIs. The viewing conditions in both testing laboratories were set to be very similar. Monocular calibrations were used. The majority of fixations recorded using either system were aligned, although data from the EyeLink system showed greater disparity magnitudes. Critically, for unaligned fixations, the data from both systems showed a majority of uncrossed fixations. These results suggest that variability in previous reports of binocular fixation alignment is attributable to the specific viewing conditions associated with a particular experiment (variables such as luminance and viewing distance), rather than acquisition and analysis software and hardware.<br/

Eye Movements and Fixation-Related Potentials in Reading: A Review

The present review is addressed to researchers in the field of reading and psycholinguistics who are both familiar with and new to co-registration research of eye movements (EMs) and fixation related-potentials (FRPs) in reading. At the outset, we consider a conundrum relating to timing discrepancies between EM and event related potential (ERP) effects. We then consider the extent to which the co-registration approach might allow us to overcome this and thereby discriminate between formal theoretical and computational accounts of reading. We then describe three phases of co-registration research before evaluating the existing body of such research in reading. The current, ongoing phase of co-registration research is presented in comprehensive tables which provide a detailed summary of the existing findings. The thorough appraisal of the published studies allows us to engage with issues such as the reliability of FRP components as correlates of cognitive processing in reading and the advantages of analysing both data streams (i.e., EMs and FRPs) simultaneously relative to each alone, as well as the current, and limited, understanding of the relationship between EM and FRP measures. Finally, we consider future directions and in particular the potential of analytical methods involving deconvolution and the potential of measurement of brain oscillatory activity

Reading sentences of uniform word length: evidence for the adaptation of the preferred saccade length during reading

In the current study we investigated the effect of removing word length variability within sentences on spatial aspects of eye movements during reading. Participants read sentences that were uniform in terms of word length, with each sentence consisting entirely of three, four, or five letter words, or a combination of these word lengths. Several interesting findings emerged. Adaptation of the preferred saccade length occurred for sentences with different uniform word length; participants would be more accurate at making short saccades while reading uniform sentences of three letter words, while they would be more accurate at making long saccades while reading uniform sentences of five letter words. Furthermore, word skipping was affected such that three and four letter words were more likely, and five letter words less likely, to be directly fixated in uniform compared to non-uniform sentences. It is argued that saccadic targeting during reading is highly adaptable and flexible towards the characteristics of the text currently being read, as opposed to the idea implemented in most current models of eye movement control during reading that readers develop a preference for making saccades of a certain length across a lifetime of experience with a given language<br/

Is orthographic information from multiple parafoveal words processed in parallel: an eye- tracking study

In the current study we investigated whether orthographic information available from one upcoming parafoveal word influences the processing of another parafoveal word. Across two experiments we used the boundary paradigm (Rayner, 1975) to present participants with an identity preview of the two words after the boundary (e.g. hot pan), a preview in which two letters were transposed between these words (e.g. hop tan), or a preview in which the same two letters were substituted (e.g. hob fan). We hypothesized that if these two words were processed in parallel in the parafovea then we may observe significant preview benefits for the condition in which the letters were transposed between words relative to the condition in which the letters were substituted. However, no such effect was observed, with participants fixating the words for the same amount of time in both conditions. This was the case both when the transposition was made between the final and first letter of the two words (e.g. hop tan as a preview of hot pan; Experiment 1) and when the transposition maintained within word letter position (e.g. pit hop as a preview of hit pop; Experiment 2). The implications of these findings are considered in relation to serial and parallel lexical processing during reading.<br/