Ryan Ringer

Impairing the useful field of view in natural scenes: tunnel vision versus general interference

A fundamental issue in visual attention is the relationship between the useful field of view (UFOV), the region of visual space where information is encoded within a single fixation, and eccentricity. A common assumption is that impairing attentional resources reduces the size of the UFOV (i.e., tunnel vision). However, most research has not accounted for eccentricity-dependent changes in spatial resolution, potentially conflating fixed visual properties with flexible changes in visual attention. Williams (1988, 1989) argued that foveal loads are necessary to reduce the size of the UFOV, producing tunnel vision. Without a foveal load, it is argued that the attentional decrement is constant across the visual field (i.e., general interference). However, other research asserts that auditory working memory (WM) loads produce tunnel vision. To date, foveal versus auditory WM loads have not been compared to determine if they differentially change the size of the UFOV. In two experiments, we tested the effects of a foveal (rotated L vs. T discrimination) task and an auditory WM (N-back) task on an extrafoveal (Gabor) discrimination task. Gabor patches were scaled for size and processing time to produce equal performance across the visual field under single-task conditions, thus removing the confound of eccentricity-dependent differences in visual sensitivity. The results showed that although both foveal and auditory loads reduced Gabor orientation sensitivity, only the foveal load interacted with retinal eccentricity to produce tunnel vision, clearly demonstrating task-specific changes to the form of the UFOV. This has theoretical implications for understanding the UFOV.

The spatiotemporal dynamics of scene gist recognition.

Viewers can rapidly extract a holistic semantic representation of a real-world scene within a single eye fixation, an ability called recognizing the gist of a scene, and operationally defined here as recognizing an images basic-level scene category. However, it is unknown how scene gist recognition unfolds over both time and space-within a fixation and across the visual field. Thus, in 3 experiments, the current study investigated the spatiotemporal dynamics of basic-level scene categorization from central vision to peripheral vision over the time course of the critical first fixation on a novel scene. The method used a window/scotoma paradigm in which images were briefly presented and processing times were varied using visual masking. The results of Experiments 1 and 2 showed that during the first 100 ms of processing, there was an advantage for processing the scene category from central vision, with the relative contributions of peripheral vision increasing thereafter. Experiment 3 tested whether this pattern could be explained by spatiotemporal changes in selective attention. The results showed that manipulating the probability of information being presented centrally or peripherally selectively maintained or eliminated the early central vision advantage. Across the 3 experiments, the results are consistent with a zoom-out hypothesis, in which, during the first fixation on a scene, gist extraction extends from central vision to peripheral vision as covert attention expands outward.

Creating a new dynamic measure of the useful field of view using gaze-contingent displays

We have developed a measure of transient changes in the useful field of view (UFOV) in simulators using gaze-contingent displays (GCDs). It can be used to evaluate safety-critical tasks such as driving or flight, and in training to increase the UFOV under cognitive load, stress, and fatigue. Unlike the established UFOV© measure, our measure can be used in simulators. Furthermore, previous peripheral detection tasks used in simulators controlled neither the targets retinal eccentricity nor stimulus intensity. Our approach overcomes these limitations by using GCDs to present stimuli producing equal performance across eccentricities under single-task conditions for two dependent measures: blur detection and Gabor orientation discrimination. We then measure attention under dual task conditions by varying cognitive load via an N-back task. Our results showed blur sensitivity varied predictably with retinal eccentricity, but detection of blur did not vary with cognitive load. Conversely, peripheral Gabor orientation discrimination showed a significant cognitive load decrement. While this method is still in development, the results suggest that a GC UFOV method is promising.

Blur detection is unaffected by cognitive load

Blur detection is affected by retinal eccentricity, but is it also affected by attentional resources? Research showing effects of selective attention on acuity and contrast sensitivity suggests that allocating attention should increase blur detection. However, research showing that blur affects selection of saccade targets suggests that blur detection may be pre-attentive. To investigate this question, we carried out experiments in which viewers detected blur in real-world scenes under varying levels of cognitive load manipulated by the N-back task. We used adaptive threshold estimation to measure blur detection thresholds at 0°, 3°, 6°, and 9° eccentricity. Participants carried out blur detection as a single task, a single task with to-be-ignored letters, or an N-back task with four levels of cognitive load (0, 1, 2, or 3-back). In Experiment 1, blur was presented gaze-contingently for occasional single eye fixations while participants viewed scenes in preparation for an easy picture recognition memory task, and the N-back stimuli were presented auditorily. The results for three participants showed a large effect of retinal eccentricity on blur thresholds, significant effects of N-back level on N-back performance, scene recognition memory, and gaze dispersion, but no effect of N-back level on blur thresholds. In Experiment 2, we replicated Experiment 1 but presented the images tachistoscopically for 200 ms (half with, half without blur), to determine whether gaze-contingent blur presentation in Experiment 1 had produced attentional capture by blur onset during a fixation, thus eliminating any effect of cognitive load on blur detection. The results with three new participants replicated those of Experiment 1, indicating that the use of gaze-contingent blur presentation could not explain the lack of effect of cognitive load on blur detection. Thus, apparently blur detection in real-world scene images is unaffected by attentional resources, as manipulated by the cognitive load produced by the N-back task.

Broadening the Horizons of Scene Gist Recognition: Aerial and Ground-based Views

Numerous studies in the last decade have used ground-based views of scenes to investigate the process of scene gist recognition. Conversely, few if any studies have investigated scene gist recognition of aerial (i.e., satellite) views. This study asks the question, how much of what we know about scene gist recognition from ground-based views directly translates to aerial views? Fifty-two participants were randomly assigned to Aerial and Ground-based conditions, with processing times (SOA) and scene categories varied within-subjects. Stimuli were monochrome photographs from 10 categories: 5 Natural: coast, desert, forest, mountain, river; 5 Man-made: airport, city, golf-course, residential, stadium. Aerial images were from Google Earth©. Both target and mask images were presented for 24 ms, with SOAs of 24-94 ms plus a no-mask condition. Participants then chose between all 10 categories. As predicted, ground-based views were recognized more accurately than aerial views. However, contrary to predictions, aerial view recognition did not benefit more from additional processing time than ground-based view recognition. Aerial view performance with no mask was worse than ground-based view performance at 24 ms SOA. Thus, gist perception of aerial views is more data (information) limited than resource (time) limited, perhaps because they are “accidental views” (Biederman, 1987). An additional analysis collapsed all 10 basic level categories into 2 superordinate level “Natural” and “Man-made” categories. For ground-based views, Natural categories were consistently high, whereas Man-made categories benefited from additional processing time. However, for aerial views, both Natural and Man-made categories benefited equally from additional processing time. Nevertheless, confusion matrices for the 10 basic level categories and responses showed a correlation of .80 across the Aerial and Ground-based views, suggesting that discriminability between categories is similar across aerial and ground-based views. Further research will investigate what information both aerial and ground-based views contain, and what information aerial views lack.

Measuring the useful field of view during simulated driving with gaze-contingent displays

Objective: We aimed to develop and test a new dynamic measure of transient changes to the useful field of view (UFOV), utilizing a gaze-contingent paradigm for use in realistic simulated environments. Background: The UFOV, the area from which an observer can extract visual information during a single fixation, has been correlated with driving performance and crash risk. However, some existing measures of the UFOV cannot be used dynamically in realistic simulators, and other UFOV measures involve constant stimuli at fixed locations. We propose a gaze-contingent UFOV measure (the GC-UFOV) that solves the above problems. Methods: Twenty-five participants completed four simulated drives while they concurrently performed an occasional gaze-contingent Gabor orientation discrimination task. Gabors appeared randomly at one of three retinal eccentricities (5°, 10°, or 15°). Cognitive workload was manipulated both with a concurrent auditory working memory task and with driving task difficulty (via presence/absence of lateral wind). Results: Cognitive workload had a detrimental effect on Gabor discrimination accuracy at all three retinal eccentricities. Interestingly, this accuracy cost was equivalent across eccentricities, consistent with previous findings of “general interference” rather than “tunnel vision.” Conclusion: The results showed that the GC-UFOV method was able to measure transient changes in UFOV due to cognitive load in a realistic simulated environment. Application: The GC-UFOV paradigm developed and tested in this study is a novel and effective tool for studying transient changes in the UFOV due to cognitive load in the context of complex real-world tasks such as simulated driving.

A novel approach to measuring the useful field of view in simulated real-world environments using gaze contingent displays: the GC-UFOV

The Useful Field of View (UFOV) task assesses attentional breadth within a single glance. The UFOV has successfully predicted changes in attention that have real-world consequences (e.g. automobile collision likelihood), however its design prevents it from being incorporated into simulated environments (e.g. driving/flight simulators). Additionally, the UFOV task and other attentional breadth measures (e.g. the peripheral detection task) do not disentangle attention from hard-wired perceptual properties that change with retinal eccentricity (e.g., spatial resolution via cortical magnification). We therefore developed an alternative method of measuring attentional breadth using gaze-contingent (GC) displays, the GC-UFOV. Thirteen participants completed four sessions of testing to determine the effect of a secondary task (auditory N-back) on Gabor patch orientation discrimination at four retinal eccentricities (0o, 3o, 6o, and 9o). Gabor patches were occasionally presented gaze-contingently for single eye fixations while participants completed a scene recognition memory task. Gabors were size-thresholded under single-task conditions to disentangle eccentricity-dependent acuity from changes in attention occurring between single and dual-task conditions, while N-back levels were thresholded to ensure that cognitive load was equivalent across participants. Results showed a significant decrease in orientation sensitivity in the dual-task condition, but not as a function of retinal eccentricity. We conclude that interference with executive attention produces general interference with visual attention equally across retinal eccentricity. N-back sensitivity was only minimally impaired under dual-task conditions compared to single-task trials. Picture recognition memory was no different between N-back single and dual tasks, but was significantly better in the Gabor single task condition. Thus, the Gabor task did not interfere with processing picture information, making this method ideal for use in simulated real-world tasks. Furthermore, we propose that future adaptations of this method employ other ecologically valid sources of cognitive load (e.g., stress, traffic density) to observe their effects on attentional breadth. Meeting abstract presented at VSS 2015.

Older Adult Multitasking Performance Using a Gaze-Contingent Useful Field of View:

Objective We implemented a gaze-contingent useful field of view paradigm to examine older adult multitasking performance in a simulated driving environment. Background Multitasking refers to the ability to manage multiple simultaneous streams of information. Recent work suggests that multitasking declines with age, yet the mechanisms supporting these declines are still debated. One possible framework to better understand this phenomenon is the useful field of view, or the area in the visual field where information can be attended and processed. In particular, the useful field of view allows for the discrimination of two competing theories of real-time multitasking, a general interference account and a tunneling account. Methods Twenty-five older adult subjects completed a useful field of view task that involved discriminating the orientation of lines in gaze-contingent Gabor patches appearing at varying eccentricities (based on distance from the fovea) as they operated a vehicle in a driving simulator. In half of the driving scenarios, subjects also completed an auditory two-back task to manipulate cognitive workload, and during some trials, wind was introduced as a means to alter general driving difficulty. Results Consistent with prior work, indices of driving performance were sensitive to both wind and workload. Interestingly, we also observed a decline in Gabor patch discrimination accuracy under high cognitive workload regardless of eccentricity, which provides support for a general interference account of multitasking. Conclusion The results showed that our gaze-contingent useful field of view paradigm was able to successfully examine older adult multitasking performance in a simulated driving environment. Application This study represents the first attempt to successfully measure dynamic changes in the useful field of view for older adults completing a multitasking scenario involving driving.

Developing a New Measure of the Useful Field of View for Use in Dynamic Real-World Scene Viewing

In real-world contexts, such as driving, a person’s breadth of attention, or useful field of view (UFOV), can have life or death consequences, with a narrower UFOV associated with increased accident risk (e.g., Clay et al., 2005). However, existing measures of the UFOV have important limitations. Some cannot be used in dynamic viewing of real-world scenes, while others (e.g., peripheral detection tasks) do not control for retinal eccentricity or eccentricity-dependent contrast sensitivity. The current experiment aimed to develop a novel measure of the UFOV that overcomes these limitations. Our dependent measure was the detection of extrafoveal image blur in real-world scenes as a secondary task, while participants concurrently engaged in an attention-demanding primary task. The retinal eccentricity of the image blur was controlled through gaze-contingent presentation on occasional single fixations. Eccentricity-dependent contrast sensitivity was held constant in the following way. Blurred images contained a circular region of high resolution (3°, 6°, or 9° radius) centered on fixation, with a constant level of low-pass filtered imagery beyond that eccentricity. Each eccentricity was paired with a unique blur level such that, in a single-task blur detection task, blur detectability was held constant across eccentricities. Our first experiment, which disallowed eye movements, used a within-subjects design (n = 16) and occasional briefly flashed photographs of real-world scenes, half of which were blurred, while monitoring the viewers eyes to ensure central fixation. To measure the effects of cognitive load on blur detection, participants concurrently did an auditory N-back task (with N = 0, 2, or 3). Results showed that as N-back level increased, blur detection significantly decreased, but did not interact with eccentricity—consistent with a general interference effect rather than tunnel vision (Crundall, Underwood & Chapman, 1999). Follow-up experiments will allow free viewing of scenes, and occasionally present blur for