Joint contributions of preview and task instructions on visual search strategy selection.

People tend to employ suboptimal attention control strategies during visual search. Here we question why people are suboptimal, specifically investigating how knowledge of the optimal strategies and the time available to apply such strategies affect strategy use. We used the Adaptive Choice Visual Search (ACVS), a task designed to assess attentional control optimality. We used explicit strategy instructions to manipulate explicit strategy knowledge, and we used display previews to manipulate time to apply the strategies. In the first two experiments, the strategy instructions increased optimality. However, the preview manipulation did not significantly boost optimality for participants who did not receive strategy instruction. Finally, in Experiments 3A and 3B, we jointly manipulated preview and instruction with a larger sample size. Preview and instruction both produced significant main effects; furthermore, they interacted significantly, such that the beneficial effect of instructions emerged with greater preview time. Taken together, these results have important implications for understanding the strategic use of attentional control. Individuals with explicit knowledge of the optimal strategy are more likely to exploit relevant information in their visual environment, but only to the extent that they have the time to do so.

Assessing the generality of strategy optimization across distinct attentional tasks.

Individuals vary substantially in the degree to which they optimize their performance in attentional tasks. How do such individual markers of attentional strategy relate across different tasks? Previous research has failed to observe significant correlations in strategy optimization between distinct visual search tasks (Clarke et al., 2022); suggesting that strategy optimization is not unitary, or determined by a single trait variable. Here we test whether strategy optimization shows some degree of generality, specifically across tasks with similar attentional components. We employed the Adaptive Choice Visual Search (ACVS; Irons & Leber, 2018a), a visual search paradigm designed to directly measure attentional control strategy. In 2 studies, we had participants complete the ACVS and a modified, but similar, task with 1 altered attentional component (specifically, the requirement to use feature-based attention and enumeration, respectively). We found positive correlations in strategy optimization between tasks that do versus do not involve feature-based attention (r = .38, p = .0068) and across tasks that do versus do not require enumeration (r = .33, p = .018). These results provide novel evidence for generality of strategy optimization, although the strength of the correlations was weaker than the within-task test-retest reliability of strategy measurements. Thus, while some generality exists, strategy optimization appears to be quite heterogeneous. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Stable individual differences in strategies within, but not between, visual search tasks.

A striking range of individual differences has recently been reported in three different visual search tasks. These differences in performance can be attributed to strategy, that is, the efficiency with which participants control their search to complete the task quickly and accurately. Here, we ask whether an individual's strategy and performance in one search task is correlated with how they perform in the other two. We tested 64 observers and found that even though the test-retest reliability of the tasks was high, an observer's performance and strategy in one task was not predictive of their behaviour in the other two. These results suggest search strategies are stable over time, but context-specific. To understand visual search, we therefore need to account not only for differences between individuals but also how individuals interact with the search task and context.

RidA Proteins Protect against Metabolic Damage by Reactive Intermediates.

The Rid (YjgF/YER057c/UK114) protein superfamily was first defined by sequence homology with available protein sequences from bacteria, archaea, and eukaryotes (L. Parsons, N. Bonander, E. Eisenstein, M. Gilson, et al., Biochemistry 42:80-89, 2003, https://doi.org/10.1021/bi020541w). The archetypal subfamily, RidA (reactive intermediate deaminase A), is found in all domains of life, with the vast majority of free-living organisms carrying at least one RidA homolog. In over 2 decades, close to 100 reports have implicated Rid family members in cellular processes in prokaryotes, yeast, plants, and mammals. Functional roles have been proposed for Rid enzymes in amino acid biosynthesis, plant root development and nutrient acquisition, cellular respiration, and carcinogenesis. Despite the wealth of literature and over a dozen high-resolution structures of different RidA enzymes, their biochemical function remained elusive for decades. The function of the RidA protein was elucidated in a bacterial model system despite (i) a minimal phenotype of ridA mutants, (ii) the enzyme catalyzing a reaction believed to occur spontaneously, and (iii) confusing literature on the pleiotropic effects of RidA homologs in prokaryotes and eukaryotes. Subsequent work provided the physiological framework to support the RidA paradigm in Salmonella enterica by linking the phenotypes of mutants lacking ridA to the accumulation of the reactive metabolite 2-aminoacrylate (2AA), which damaged metabolic enzymes. Conservation of enamine/imine deaminase activity of RidA enzymes from all domains raises the likelihood that, despite the diverse phenotypes, the consequences when RidA is absent are due to accumulated 2AA (or a similar reactive enamine) and the diversity of metabolic phenotypes can be attributed to differences in metabolic network architecture. The discovery of the RidA paradigm in S. enterica laid a foundation for assessing the role of Rid enzymes in diverse organisms and contributed fundamental lessons on metabolic network evolution and diversity in microbes. This review describes the studies that defined the conserved function of RidA, the paradigm of enamine stress in S. enterica, and emerging studies that explore how this paradigm differs in other organisms. We focus primarily on the RidA subfamily, while remarking on our current understanding of the other Rid subfamilies. Finally, we describe the current status of the field and pose questions that will drive future studies on this widely conserved protein family to provide fundamental new metabolic information.

A methodological toolbox for investigating attentional strategy.

Strategy is a crucial determinant for how attention is controlled. In recent years, researchers have deployed a growing variety of manipulations and dependent measures in service of understanding strategy. This work has revealed a striking degree of diversity and suboptimality in the use of attention, and it prompts the realization that more research on strategy is needed in order to fully understand and explain how attention works. Here, we highlight several approaches to investigate strategy, in what can be considered a 'methodological toolbox' for researchers. These methods can be customized and combined flexibly in what we hope will be a continued expansion of inquiry into this important domain.

Taking stock: The role of environmental appraisal in the strategic use of attentional control.

There are many strategies we can use to control attention when approaching a visual search task, but some are more effective than others. How do we choose the most optimal strategy? We have proposed that individuals must appraise the stimulus environment, taking in relevant statistical information about task-relevant features. In the present experiments, we examined whether interfering with the appraisal process via a secondary task decreases participants' use of the optimal strategy. We used a modified version of the Adaptive Choice Visual Search paradigm whereby individuals can freely search for either of two targets on every trial. Each search display was preceded by a colored environmental preview, offering participants time to appraise the display and determine which target would be more optimal to search for. On some blocks, participants also completed a secondary task - a central line-length judgment - either before or during this colored preview. We found that participants were significantly less likely to search optimally when the line task occurred during the colored preview than when it occurred beforehand or was absent. Insofar as the secondary task disrupts an individual's ability to engage in appraisal, these results support the need for such an appraisal mechanism in the optimal choice of attentional control settings.

Characterizing individual variation in the strategic use of attentional control.

Goal-directed attentional control can substanially aid visual search, but only if it is recruited in an effective manner. Previously we found that strategies chosen to control attention vary considerably across individuals, and we proposed that effort avoidance may lead some individuals to choose suboptimal strategies. Here we present a more thorough analysis of individual differences in attentional control strategies. We used the adaptive choice visual search, which provides a method to quantify an individual's attentional control strategy in a dynamically changing, unconstrained environment. We found that individual's strategy choices are highly reliable across sessions, suggesting that attentional control strategies are stable and trait-like. In Experiment 2, we explored the extent to which strategy use was related to subjective evaluations of effort and performance. Results showed that the extent to which individuals found the optimal strategy to be effortful and effective predicted their likelihood of making optimal choices on a subsequent choice block. These results provide the first evidence for a relationship between effort and strategic attentional control, and they highlight the important and often neglected role of strategy in understanding attentional control. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Adaptive face coding contributes to individual differences in facial expression recognition independently of affective factors.

There are large, reliable individual differences in the recognition of facial expressions of emotion across the general population. The sources of this variation are not yet known. We investigated the contribution of a key face perception mechanism, adaptive coding, which calibrates perception to optimize discrimination within the current perceptual "diet." We expected that a facial expression system that readily recalibrates might boost sensitivity to variation among facial expressions, thereby enhancing recognition ability. We measured adaptive coding strength with an established facial expression aftereffect task and measured facial expression recognition ability with 3 tasks optimized for the assessment of individual differences. As expected, expression recognition ability was positively associated with the strength of facial expression aftereffects. We also asked whether individual variation in affective factors might contribute to expression recognition ability, given that clinical levels of such traits have previously been linked to ability. Expression recognition ability was negatively associated with self-reported anxiety but not with depression, mood, or degree of autism-like or empathetic traits. Finally, we showed that the perceptual factor of adaptive coding contributes to variation in expression recognition ability independently of affective factors. (PsycINFO Database Record

Pre-stimulus pupil dilation and the preparatory control of attention.

Task preparation involves multiple component processes, including a general evaluative process that signals the need for adjustments in control, and the engagement of task-specific control settings. Here we examined the dynamics of these different mechanisms in preparing the attentional control system for visual search. We explored preparatory activity using pupil dilation, a well-established measure of task demands and effortful processing. In an initial exploratory experiment, participants were cued at the start of each trial to search for either a salient color singleton target (an easy search task) or a low-salience shape singleton target (a difficult search task). Pupil dilation was measured during the preparation period from cue onset to search display onset. Mean dilation was larger in preparation for the difficult shape target than the easy color target. In two additional experiments, we sought to vary effects of evaluative processing and task-specific preparation separately. Experiment 2 showed that when the color and shape search tasks were matched for difficulty, the shape target no longer evoked larger dilations, and the pattern of results was in fact reversed. In Experiment 3, we manipulated difficulty within a single feature dimension, and found that the difficult search task evoked larger dilations. These results suggest that pupil dilation reflects expectations of difficulty in preparation for a search task, consistent with the activity of an evaluative mechanism. We did not find consistent evidence for relationship between pupil dilation and search performance (accuracy and response timing), suggesting that pupil dilation during search preparation may not be strongly linked to ongoing task-specific preparation.

Face identity recognition in simulated prosthetic vision is poorer than previously reported and can be improved by caricaturing.

The visual prosthesis (or "bionic eye") has become a reality but provides a low resolution view of the world. Simulating prosthetic vision in normal-vision observers, previous studies report good face recognition ability using tasks that allow recognition to be achieved on the basis of information that survives low resolution well, including basic category (sex, age) and extra-face information (hairstyle, glasses). Here, we test within-category individuation for face-only information (e.g., distinguishing between multiple Caucasian young men with hair covered). Under these conditions, recognition was poor (although above chance) even for a simulated 40×40 array with all phosphene elements assumed functional, a resolution above the upper end of current-generation prosthetic implants. This indicates that a significant challenge is to develop methods to improve face identity recognition. Inspired by "bionic ear" improvements achieved by altering signal input to match high-level perceptual (speech) requirements, we test a high-level perceptual enhancement of face images, namely face caricaturing (exaggerating identity information away from an average face). Results show caricaturing improved identity recognition in memory and/or perception (degree by which two faces look dissimilar) down to a resolution of 32×32 with 30% phosphene dropout. Findings imply caricaturing may offer benefits for patients at resolutions realistic for some current-generation or in-development implants.

Choosing attentional control settings in a dynamically changing environment.

Goal-directed attentional control supports efficient visual search by prioritizing relevant stimuli in the environment. Previous research has shown that goal-directed control can be configured in many ways, and often multiple control settings can be used to achieve the same goal. However, little is known about how control settings are selected. We explored the extent to which the configuration of goal-directed control is driven by performance maximization (optimally configuring settings to maximize speed and accuracy) and effort minimization (selecting the least effortful settings). We used a new paradigm, adaptive choice visual search, which allows participants to choose one of two available targets (a red or a blue square) on each trial. Distractor colors vary predictively across trials, such that the optimal target switches back and forth throughout the experiment. Results (N = 43) show that participants chose the optimal target most often, updating to the new target when the environment changed, supporting performance maximization. However, individuals were sluggish to update to the optimal color, consistent with effort minimization. Additionally, we found a surprisingly high rate of nonoptimal choices and switching between targets, which could not be explained by either factor. Analysis of participants' self-reported search strategy revealed substantial individual differences in the control strategies used. In sum, the adaptive choice visual search enables a fresh approach to studying goal-directed control. The results contribute new evidence that control is partly determined by both performance maximization and effort minimization, as well as at least one additional factor, which we speculate to include novelty seeking.

A cultural setting where the other-race effect on face recognition has no social-motivational component and derives entirely from lifetime perceptual experience.

Competing approaches to the other-race effect (ORE) see its primary cause as either a lack of motivation to individuate social outgroup members, or a lack of perceptual experience with other-race faces. Here, we argue that the evidence supporting the social-motivational approach derives from a particular cultural setting: a high socio-economic status group (typically US Whites) looking at the faces of a lower status group (US Blacks) with whom observers typically have at least moderate perceptual experience. In contrast, we test motivation-to-individuate instructions across five studies covering an extremely wide range of perceptual experience, in a cultural setting of more equal socio-economic status, namely Asian and Caucasian participants (N = 480) tested on Asian and Caucasian faces. We find no social-motivational component at all to the ORE, specifically: no reduction in the ORE with motivation instructions, including for novel images of the faces, and at all experience levels; no increase in correlation between own- and other-race face recognition, implying no increase in shared processes; and greater (not the predicted less) effort applied to distinguishing other-race faces than own-race faces under normal ("no instructions") conditions. Instead, the ORE was predicted by level of contact with the other-race. Our results reject both pure social-motivational theories and also the recent Categorization-Individuation model of Hugenberg, Young, Bernstein, and Sacco (2010). We propose a new dual-route approach to the ORE, in which there are two causes of the ORE-lack of motivation, and lack of experience--that contribute differently across varying world locations and cultural settings.

A Rhodobacter sphaeroides protein mechanistically similar to Escherichia coli DksA regulates photosynthetic growth.

ABSTRACT DksA is a global regulatory protein that, together with the alarmone ppGpp, is required for the "stringent response" to nutrient starvation in the gammaproteobacterium Escherichia coli and for more moderate shifts between growth conditions. DksA modulates the expression of hundreds of genes, directly or indirectly. Mutants lacking a DksA homolog exhibit pleiotropic phenotypes in other gammaproteobacteria as well. Here we analyzed the DksA homolog RSP2654 in the more distantly related Rhodobacter sphaeroides, an alphaproteobacterium. RSP2654 is 42% identical and similar in length to E. coli DksA but lacks the Zn finger motif of the E. coli DksA globular domain. Deletion of the RSP2654 gene results in defects in photosynthetic growth, impaired utilization of amino acids, and an increase in fatty acid content. RSP2654 complements the growth and regulatory defects of an E. coli strain lacking the dksA gene and modulates transcription in vitro with E. coli RNA polymerase (RNAP) similarly to E. coli DksA. RSP2654 reduces RNAP-promoter complex stability in vitro with RNAPs from E. coli or R. sphaeroides, alone and synergistically with ppGpp, suggesting that even though it has limited sequence identity to E. coli DksA (DksAEc), it functions in a mechanistically similar manner. We therefore designate the RSP2654 protein DksARsp. Our work suggests that DksARsp has distinct and important physiological roles in alphaproteobacteria and will be useful for understanding structure-function relationships in DksA and the mechanism of synergy between DksA and ppGpp. IMPORTANCE The role of DksA has been analyzed primarily in the gammaproteobacteria, in which it is best understood for its role in control of the synthesis of the translation apparatus and amino acid biosynthesis. Our work suggests that DksA plays distinct and important physiological roles in alphaproteobacteria, including the control of photosynthesis in Rhodobacter sphaeroides. The study of DksARsp, should be useful for understanding structure-function relationships in the protein, including those that play a role in the little-understood synergy between DksA and ppGpp.

Can attentional control settings be maintained for two color-location conjunctions? Evidence from an RSVP task.

Previous investigations of the ability to maintain separate attentional control settings for different spatial locations have relied principally on a go/no-go spatial-cueing paradigm. The results have suggested that control of attention is accomplished only late in processing. However, the go/no-go task does not provide strong incentives to withhold attention from irrelevant color-location conjunctions. We used a modified version of the task in which failing to adopt multiple control settings would be detrimental to performance. Two RSVP streams of colored letters appeared to the left and right of fixation. Participants searched for targets that were a conjunction of color and location, so that the target color for one stream acted as a distractor when presented in the opposite stream. Distractors that did not match the target conjunctions nevertheless captured attention and interfered with performance. This was the case even when the target conjunctions were previewed early in the trial prior to the target (Exp. 2). However, distractor interference was reduced when the upcoming distractor was previewed early on in the trial (Exp. 3). Attentional selection of targets by color-location conjunctions may be effective if facilitative attentional sets are accompanied by the top-down inhibition of irrelevant items.

All set! Evidence of simultaneous attentional control settings for multiple target colors.

Although models of visual search have often assumed that attention can only be set for a single feature or property at a time, recent studies have suggested that it may be possible to maintain more than one attentional control setting. The aim of the present study was to investigate whether spatial attention could be guided by multiple attentional control settings for color. In a standard spatial cueing task, participants searched for either of two colored targets accompanied by an irrelevantly colored distractor. Across five experiments, results consistently showed that nonpredictive cues matching either target color produced a significant spatial cueing effect, while irrelevantly colored cues did not. This was the case even when the target colors could not be linearly separated from irrelevantly cue colors in color space, suggesting that participants were not simply adopting one general color set that included both target colors. The results could not be explained by intertrial priming by previous targets, nor could they be explained by a single inhibitory set for the distractor color. Overall, the results are most consistent with the maintenance of multiple attentional control settings.