Visual Search Asymmetry Research Articles

Gravity's impact on visual search asymmetries: Is visual gravitational motion a distinct visual feature or a familiar dynamic event?

A wealth of converging research lines has led support to the notion that specialized neural processes output a priori information about the expected effects of gravity to fine-tune motor and perceptual responses to dynamic events. Arguably, these putative internal models of gravity might modulate the efficiency in visual search for objects conforming or not to gravitationally coherent dynamics. In the present work, we explored this possibility with a visual search task involving arrays of two to eight objects moving periodically back and forth. The target could be an accelerating/decelerating ball (as if bouncing on earth's surface-1g) with distractors moving at a constant speed (0g) or the reverse. Moreover, the direction of the gravitational pull, as implied by the 1g motion patterns, could be aligned or misaligned with Earth's gravity. Overall, searches for 1g targets were more efficient than 0g targets except, notably, when stimuli displays were congruent with Earth's gravitational pull, in which case the visual search asymmetry is significantly reduced. Outcomes are interpreted as reflecting the joint and mutually cancelling contribution of low-level detection of acceleration patterns and higher level detection of unexpected violations of gravitational motion. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Emotion recognition, not attentional capture, drives visual search asymmetries to emotional expressions

Emotion recognition, not attentional capture, drives visual search asymmetries to emotional expressions

Can a saliency model using feature sets derived cityscapes predict cultural differences in visual search asymmetry?

Can a saliency model using feature sets derived cityscapes predict cultural differences in visual search asymmetry?

Visual search asymmetries are explained by visual homogeneity

Visual search asymmetries are explained by visual homogeneity

Attentional disengagement effect based on relevant features.

In visual search tasks, distractors similar to the target can attract our attention and affect the speed of attentional disengagement. The attentional disengagement refers to shifting attention away from stimuli that are not relevant to the task. Previous studies mainly focused on the attentional disengagement of one feature dimension. However, the mechanisms of different feature dimensions on attentional disengagement in single and conjunction visual search remain unclear. In the current study, we adopted the oculomotor disengagement paradigm and used saccade latency as an indicator to explore the effects of different feature dimensions of center stimuli on attentional disengagement. In both single and conjunction feature search tasks, participants began each search by fixating on a center stimulus that appeared simultaneously with search display but would not be the target. Participants were instructed to ensure the first saccade to the target location. In Experiments 1A (single feature search) and 1B (conjunction feature search), we found that the attentional disengagement was significantly delayed or accelerated when center stimuli shared color features with the target or salient distractor, but not in shape feature. Moreover, we found that the difference between the two feature dimensions might be caused by their different search difficulty (Experiment 1C). Therefore, in Experiment 2, we matched the difficulty of searching for color and shape tasks before exploring whether there were differences in the effects of different feature dimensions on attentional disengagement. However, the results in Experiment 2 were similar to those in Experiment 1A, indicating that the different effects of feature dimensions on attentional disengagement were caused by feature asymmetry. Therefore, in Experiment 3, we improved the salient discernibility of shape dimension and matched color search to it. The results showed that although the attentional disengagement was delayed in shape dimension, it was still smaller than that in color dimension. Our results supported that goal-oriented attention sets were the main cause of delayed attentional disengagement. By series of experiments, we found that the utilization of different feature dimensions was associated with task difficulty and the features asymmetry in both single and conjunction visual search.

Asymmetric visual representation of sex from facial appearance

We efficiently infer others’ traits from their faces, and these inferences powerfully shape our social behaviour. Here, we investigated how sex is represented in facial appearance. Based on previous findings from sex-judgment tasks, we hypothesized that the perceptual encoding of sex is not balanced but rather polarized: for the processes that generate a sex percept, the default output is “male,” and the representation of female faces extends that of the male, engaging activity over unique detectors that are not activated by male faces. We tested this hypothesis with the logic of Treisman’s studies of visual search asymmetries, predicting that observers should more readily detect the presence of female faces amongst male distractors than vice versa. Across three experiments (N = 32 each), each using different face stimuli, we confirmed this prediction in response time and sensitivity measures. We apply GIST analyses to the face stimuli to exclude that the search asymmetry is explained by differences in image homogeneity. These findings demonstrate a property of the coding that links facial appearance with a significant social trait: the female face is coded as an extension of a male default. We offer a mechanistic description of perceptual detectors to account for our findings and posit that the origins of this polarized coding scheme are an outcome of biased early developmental experience.

Metacognitive asymmetries in visual perception.

People have better metacognitive sensitivity for decisions about the presence compared to the absence of objects. However, it is not only objects themselves that can be present or absent, but also parts of objects and other visual features. Asymmetries in visual search indicate that a disadvantage for representing absence may operate at these levels as well. Furthermore, a processing advantage for surprising signals suggests that a presence/absence asymmetry may be explained by absence being passively represented as a default state, and presence as a default-violating surprise. It is unknown whether the metacognitive asymmetry for judgments about presence and absence extends to these different levels of representation (object, feature, and default violation). To address this question and test for a link between the representation of absence and default reasoning more generally, here we measure metacognitive sensitivity for discrimination judgments between stimuli that are identical except for the presence or absence of a distinguishing feature, and for stimuli that differ in their compliance with an expected default state.

Visual Search Asymmetry Due to the Relative Magnitude Represented by Number Symbols.

In visual search tasks, physically large target stimuli are more easily identified among small distractors than are small targets among large distractors. The present study extends this finding by presenting preliminary evidence of a new search asymmetry: stimuli that symbolically represent larger magnitude are identified more easily among featurally equivalent distractors that represent smaller magnitude. Participants performed a visual search task using line-segment digits representing the numbers 2 and 5, and the numbers 6 and 9, as well as comparable non-numeric control stimuli. In three experiments, we found that search times are faster when the target is a digit that represents a larger magnitude than the distractor, although this pattern was not evident in one additional experiment. The results provide suggestive evidence that the magnitude of a number symbol can affect perceptual comparisons between number symbols, and that the semantic meaning of a target stimulus can systematically affect visual search.

Effect of Global and Local Processing on Visual Search Asymmetry

Effect of Global and Local Processing on Visual Search Asymmetry

Asymmetric visual representation of sex from human body shape

We efficiently infer others' states and traits from their appearance, and these inferences powerfully shape our social behaviour. One key trait is sex, which is strongly cued by the appearance of the body. What are the visual representations that link body shape to sex? Previous studies of visual sex judgment tasks find observers have a bias to report “male”, particularly for ambiguous stimuli. This finding implies a representational asymmetry – that for the processes that generate a sex percept, the default output is “male”, and “female” is determined by the presence of additional perceptual evidence. That is, female body shapes are positively coded by reference to a male default shape. This perspective makes a novel prediction in line with Treisman's studies of visual search asymmetries: female body targets should be more readily detected amongst male distractors than vice versa. Across 10 experiments (N = 32 each) we confirmed this prediction and ruled out alternative low-level explanations. The asymmetry was found with profile and frontal body silhouettes, frontal photographs, and schematised icons. Low-level confounds were controlled by balancing silhouette images for size and homogeneity, and by matching physical properties of photographs. The female advantage was nulled for inverted icons, but intact for inverted photographs, suggesting reliance on distinct cues to sex for different body depictions. Together, these findings demonstrate a principle of the perceptual coding that links bodily appearance with a significant social trait: the female body shape is coded as an extension of a male default. We conclude by offering a visual experience account of how these asymmetric representations arise in the first place.

A visual search asymmetry for relative novelty in the visual field based on sensory adaptation

The ability to detect sudden changes in the environment is important for survival. However, studies of “change blindness” have shown that image differences are hard to detect when a time delay or a mask is imposed between the different images. However, when sensory adaptation is permitted by accurate fixation, we find that change detection is not only possible but asymmetrical: a single changed target amongst 15 unchanging distractors is much easier to detect than a target defined by its lack of change. Although adaptation may selectively reduce the apparent contrast of unchanged objects, the asymmetry in “change salience” cannot be attributed to any such reduction because genuine reductions in target contrast increase, rather than decrease, target detectability. Analogous results preclude attribution to apparent differences between (a) target onset and distractor onset and (b) their temporal frequencies (both flickered at 7.5 Hz, minimizing afterimages). Our results demonstrate a hitherto underappreciated (or unappreciated) advantage conferred by low-level sensory adaptation: it automatically elevates the salience of previously absent objects.

Visual search asymmetry depends on target-distractor feature similarity: Is the asymmetry simply a result of distractor rejection speed?

Previous studies have shown that in visual search, varying the target and distractor familiarity produces a search asymmetry: Detecting a novel target among familiar distractors is more efficient than detecting a familiar target among novel distractors. One explanation is that novel targets have enhanced salience and are detected preattentively. Conversely, familiar distractors may be easier to reject. The current study postulates that target-distractor feature similarity, in addition to target or distractor familiarity, is a key determinant of visual search efficiency. The results of two experiments reveal that visual search is more efficient when distractors are familiar regardless of target familiarity, but only when the target-distractor similarity is high. When similarity is low, the visual search asymmetry disappears and the search times become highly efficient, with search slopes not different from zero regardless of target or distractor familiarity. However, although distractor familiarity plays an important role in inducing the search asymmetry, comparisons of search efficiency in target-present and target-absent trials reveal that search asymmetries cannot be explained solely by the faster speed of rejecting familiar distractors, as proposed by previous studies. Rather, distractor familiarity influences processes outside of stimulus selection, such as search monitoring and termination decisions. Competition among bottom-up item salience effects and top-down shape recognition processes is proposed to account for these findings.

Search for Familiar and Dangerous: Not Seeing Gopnik in the Crowd

Subcultures frequently tend to have some distinct fashion style, which eventually becomes their “trademark” and drifts to the common knowledge of one culture or another. However, to what extent can these characteristics of certain groups be intervened with vast cultural heritage? We examined the influence of specific features of “gopnik” fashion on visual search performance. We conducted two experiments to investigate familiarity and threatening effects of these objects in visual search. Overall, our results demonstrate visual search asymmetry for man-like and gopnik-like objects, which could not be explained by basic features differences of these stimuli. We suggest that nowadays in Russia gopniks are represented as familiar group, rather than dangerous.

Feature reliability determines specificity and transfer of perceptual learning in orientation search.

Training can modify the visual system to produce a substantial improvement on perceptual tasks and therefore has applications for treating visual deficits. Visual perceptual learning (VPL) is often specific to the trained feature, which gives insight into processes underlying brain plasticity, but limits VPL’s effectiveness in rehabilitation. Under what circumstances VPL transfers to untrained stimuli is poorly understood. Here we report a qualitatively new phenomenon: intrinsic variation in the representation of features determines the transfer of VPL. Orientations around cardinal are represented more reliably than orientations around oblique in V1, which has been linked to behavioral consequences such as visual search asymmetries. We studied VPL for visual search of near-cardinal or oblique targets among distractors of the other orientation while controlling for other display and task attributes, including task precision, task difficulty, and stimulus exposure. Learning was the same in all training conditions; however, transfer depended on the orientation of the target, with full transfer of learning from near-cardinal to oblique targets but not the reverse. To evaluate the idea that representational reliability was the key difference between the orientations in determining VPL transfer, we created a model that combined orientation-dependent reliability, improvement of reliability with learning, and an optimal search strategy. Modeling suggested that not only search asymmetries but also the asymmetric transfer of VPL depended on preexisting differences between the reliability of near-cardinal and oblique representations. Transfer asymmetries in model behavior also depended on having different learning rates for targets and distractors, such that greater learning for low-reliability distractors facilitated transfer. These findings suggest that training on sensory features with intrinsically low reliability may maximize the generalizability of learning in complex visual environments.

The effect of cerebral asymmetries and eye scanning on pseudoneglect for a visual search task

Pseudoneglect is the tendency for the general population to over-attend to the left. While pseudoneglect is classically demonstrated using line bisection, it also occurs for visual search. The current study explored the influence of eye movements and functional cerebral asymmetry on asymmetries for visual search. In Experiment 1, 24 participants carried out a conjunction search for a target within a rectangular array. A leftward advantage for detecting targets was observed when the eyes were free to move, but not when they were restricted by short exposure durations. In Experiment 2, the effect of functional cerebral asymmetry was explored by comparing 20 right-handers and 19 left-handers. Results showed a stronger leftward bias for the right-handers, consistent with a mechanism related to cerebral asymmetry. In Experiment 3, an eye-tracker directly controlled eye movements in 25 participants. A leftward advantage emerged when the eyes were still, but not when they were free to move. Experiments 1 and 3 produced contradictory results in relation to eye movements, which may be related to task-related demands. On balance, the data suggest that asymmetries in visual search can occur in the absence of eye movements and that they are related to right hemisphere specialisation for spatial attention.

The Roles of Non-retinotopic Motions in Visual Search.

In visual search, a moving target among stationary distracters is detected more rapidly and more efficiently than a static target among moving distracters. Here we examined how this search asymmetry depends on motion signals from three distinct coordinate systems—retinal, relative, and spatiotopic (head/body-centered). Our search display consisted of a target element, distracters elements, and a fixation point tracked by observers. Each element was composed of a spatial carrier grating windowed by a Gaussian envelope, and the motions of carriers, windows, and fixation were manipulated independently and used in various combinations to decouple the respective effects of motion coordinate systems on visual search asymmetry. We found that retinal motion hardly contributes to reaction times and search slopes but that relative and spatiotopic motions contribute to them substantially. Results highlight the important roles of non-retinotopic motions for guiding observer attention in visual search.

Keep on rolling: Visual search asymmetries in 3D scenes with motion-defined targets

Keep on rolling: Visual search asymmetries in 3D scenes with motion-defined targets

Intensity of Visual Search Asymmetry Depends on Physical Property in Target-Present Trials and Search Type in Target-Absent Trials

Intensity of Visual Search Asymmetry Depends on Physical Property in Target-Present Trials and Search Type in Target-Absent Trials

Effects of tilted orientations and face-like configurations on visual search asymmetry in macaques

Visual search asymmetry has been used as an important tool for exploring cognitive mechanisms in humans. Here, we examined visual search asymmetry in two macaques toward two types of stimulus: the orientation of line stimuli and face-like stimuli. In the experiment, the monkeys were required to detect an odd target among numerous uniform distracters. The monkeys detected a tilted-lines target among horizontal- or vertical-lined distracters significantly faster than a horizontal- or vertical-lined target among tilted-lined distracters, regardless of the display size. However, unlike the situation in which inverted-face stimuli were introduced as distracters, this effect was diminished if upright-face stimuli were used as distracters. Additionally, monkeys detected an upright-face target among inverted-face distracters significantly faster than an inverted-face target among upright-face distracters, regardless of the display size. These results demonstrate that macaques can search a target efficiently to detect both tilted lines among non-tilted lines and upright faces among inverted faces. This clarifies that there are several types of visual search asymmetry in macaques.

Visual Search Asymmetries in Heavy Clutter: Implications for Display Design

An experiment aimed to test whether design of symbology to produce visual search asymmetries might facilitate target detection in cluttered displays. A visual search asymmetry exists between two stimuli when a target of one type is found efficiently among distractors of the second type but a target of the second type is found with difficulty among distractors of the first type. Asymmetries have generally been studied within relatively sparse displays. In the present study, the authors tested whether an asymmetry driven by stimulus familiarity persists within heavily cluttered imagery. In this study, 10 participants performed a visual search task using stimuli (canonical vs. reversed Ns) known to produce a search asymmetry. Search stimuli were embedded within geospatial images containing either low or high levels of clutter. A decision theoretic index of sensitivity served as the dependent measure. The search asymmetry was robust against the presence of heavy display clutter. Specifically, sensitivity was greater when the target was a reversed N rather than an N, and this pattern remained within cluttered displays. Time-accuracy analysis revealed that the search asymmetry increased the rate of information accumulation roughly equally within low- and high- clutter images. Search asymmetries are robust against heavy, spatially continuous visual clutter. Design of display symbology to produce visual search asymmetries can offset the costs of visual clutter, maximizing detectability of task-critical information in complex displays.