Working memory control predicts fixation duration in scene-viewing.

When viewing scenes, observers differ in how long they linger at each fixation location and how far they move their eyes between fixations. What factors drive these differences in eye-movement behaviors? Previous work suggests individual differences in working memory capacity may influence fixation durations and saccade amplitudes. In the present study, participants (N = 98) performed two scene-viewing tasks, aesthetic judgment and memorization, while viewing 100 photographs of real-world scenes. Working memory capacity, working memory processing ability, and fluid intelligence were assessed with an operation span task, a memory updating task, and Raven's Advanced Progressive Matrices, respectively. Across participants, we found significant effects of task on both fixation durations and saccade amplitudes. At the level of each individual participant, we also found a significant relationship between memory updating task performance and participants' fixation duration distributions. However, we found no effect of fluid intelligence and no effect of working memory capacity on fixation duration or saccade amplitude distributions, inconsistent with previous findings. These results suggest that the ability to flexibly maintain and update working memory is strongly related to fixation duration behavior.

Meaning and expected surfaces combine to guide attention during visual search in scenes.

How do spatial constraints and meaningful scene regions interact to control overt attention during visual search for objects in real-world scenes? To answer this question, we combined novel surface maps of the likely locations of target objects with maps of the spatial distribution of scene semantic content. The surface maps captured likely target surfaces as continuous probabilities. Meaning was represented by meaning maps highlighting the distribution of semantic content in local scene regions. Attention was indexed by eye movements during the search for target objects that varied in the likelihood they would appear on specific surfaces. The interaction between surface maps and meaning maps was analyzed to test whether fixations were directed to meaningful scene regions on target-related surfaces. Overall, meaningful scene regions were more likely to be fixated if they appeared on target-related surfaces than if they appeared on target-unrelated surfaces. These findings suggest that the visual system prioritizes meaningful scene regions on target-related surfaces during visual search in scenes.

Visual and verbal working memory loads interfere with scene-viewing.

Working memory is thought to be divided into distinct visual and verbal subsystems. Studies of visual working memory frequently use verbal working memory tasks as control conditions and/or use articulatory suppression to ensure that visual load is not transferred to verbal working memory. Using these verbal tasks relies on the assumption that the verbal working memory load will not interfere with the same processes as visual working memory. In the present study, participants maintained a visual or verbal working memory load as they simultaneously viewed scenes while their eye movements were recorded. Because eye movements and visual working memory are closely linked, we anticipated the visual load would interfere with scene-viewing (and vice versa), while the verbal load would not. Surprisingly, both visual and verbal memory loads interfered with scene-viewing behavior, while eye movements during scene-viewing did not significantly interfere with performance on either memory task. These results suggest that a verbal working memory load can interfere with eye movements in a visual task.

Eye Movements in Real-World Scene Photographs: General Characteristics and Effects of Viewing Task.

The present study examines eye movement behavior in real-world scenes with a large (N = 100) sample. We report baseline measures of eye movement behavior in our sample, including mean fixation duration, saccade amplitude, and initial saccade latency. We also characterize how eye movement behaviors change over the course of a 12 s trial. These baseline measures will be of use to future work studying eye movement behavior in scenes in a variety of literatures. We also examine effects of viewing task on when and where the eyes move in real-world scenes: participants engaged in a memorization and an aesthetic judgment task while viewing 100 scenes. While we find no difference at the mean-level between the two tasks, temporal- and distribution-level analyses reveal significant task-driven differences in eye movement behavior.

Visual working memory supports perceptual stability across saccadic eye movements.

Vision is suppressed during saccadic eye movements. To create a stable perception of the visual world we must compensate for the gaps in visual input caused by this suppression. Some theories of perceptual stability, such as the Saccade Target Object Theory (McConkie & Currie, 1996), propose that stability relies on object correspondence across saccades. According to these views, the visual system encodes features of the saccade target into visual working memory (VWM) before a saccade is made. After the saccade, participants attempt to locate those features within a small region near the fovea. If this locating process succeeds, perceptual stability is maintained. The present study investigated directly whether perceptual stability relies on VWM. If it does, perceived stability should be impaired when VWM is loaded with other visual information. Participants detected saccade target displacements while simultaneously maintaining a VWM or verbal working memory (AWM) load. In three experiments, a VWM load negatively impacted participants' ability to detect saccade target displacements and the saccade target displacement task negatively impacted memory for VWM task items. Neither of these effects were apparent when AWM was loaded, suggesting that performance on VWM and saccade target displacement detection tasks, and thus perceptual stability, relies on VWM resources. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Oh, the number of things you will process (in parallel)!

We highlight the importance of considering the variance produced during the parallel processing stage in vision and present a case for why it is useful to consider the "item" as a meaningful unit of study when investigating early visual processing in visual search tasks.

Towards a better understanding of parallel visual processing in human vision: Evidence for exhaustive analysis of visual information.

Most current models of visual processing propose that there are 2 main stages of visual processing, the first consisting of a parallel visual analysis of the scene and the second being a precise scrutiny of a few elements in the scene. Here, we present novel evidence that the first stage of processing adds systematic variance to visual processing times. When searching for a specific target, it has a behaviorally unique signature: RTs increase logarithmically with the number of items in the display and this increase is modulated by target-distractor similarity. This signature is characteristic of unlimited capacity parallel and exhaustive processing of all the elements in the scene. The function of this processing is to identify the locations in the scene containing items that are sufficiently similar to the target as to merit focused scrutiny, while discarding those that do not. We also demonstrate that stage-1 variability is sensitive to the observers' top-down goals: with identical displays, whereas RTs increase logarithmically with set size when observers are asked to find a specific target, they decrease exponentially when asked to find a unique item in the scene. (PsycINFO Database Record

Evaluating the influence of a fixated object's spatio-temporal properties on gaze control.

Despite recent progress in understanding the factors that determine where an observer will eventually look in a scene, we know very little about what determines how an observer decides where he or she will look next. We investigated the potential roles of object-level representations in the direction of subsequent shifts of gaze. In five experiments, we considered whether a fixated object's spatial orientation, implied motion, and perceived animacy affect gaze direction when shifting overt attention to another object. Eye movements directed away from a fixated object were biased in the direction it faced. This effect was not modified by implying a particular direction of inanimate or animate motion. Together, these results suggest that decisions regarding where one should look next are in part determined by the spatial, but not by the implied temporal, properties of the object at the current locus of fixation.

Integrated project views: decision support platform for drug discovery project teams.

Drug discovery teams continuously have to decide which compounds to progress and which experiments to perform next, but the data required to make informed decisions is often scattered, inaccessible, or inconsistent. In particular, data tend to be stored and represented in a compound-centric or assay-centric manner rather than project-centric as often needed for effective use in drug discovery teams. The Integrated Project Views (IPV) system has been created to fill this gap; it integrates and consolidates data from various sources in a project-oriented manner. Its automatic gathering and updating of project data not only ensures that the information is comprehensive and available on a timely basis, but also improves the data consistency. Due to the lack of suitable off-the-shelf solutions, we were prompted to develop custom functionality and algorithms geared specifically to our drug discovery decision making process. In 10 years of usage, the resulting IPV application has become very well-accepted and appreciated, which is perhaps best evidenced by the observation that standalone Excel spreadsheets are largely eliminated from project team meetings.