Asymmetries around the visual field: From retina to cortex to behavior

Visual performance varies around the visual field. It is best near the fovea compared to the periphery, and at iso-eccentric locations it is best on the horizontal, intermediate on the lower, and poorest on the upper meridian. The fovea-to-periphery performance decline is linked to the decreases in cone density, retinal ganglion cell (RGC) density, and V1 cortical magnification factor (CMF) as eccentricity increases. The origins of polar angle asymmetries are not well understood. Optical quality and cone density vary across the retina, but recent computational modeling has shown that these factors can only account for a small percentage of behavior. Here, we investigate how visual processing beyond the cone photon absorptions contributes to polar angle asymmetries in performance. First, we quantify the extent of asymmetries in cone density, midget RGC density, and V1 CMF. We find that both polar angle asymmetries and eccentricity gradients increase from cones to mRGCs, and from mRGCs to cortex. Second, we extend our previously published computational observer model to quantify the contribution of phototransduction by the cones and spatial filtering by mRGCs to behavioral asymmetries. Starting with photons emitted by a visual display, the model simulates the effect of human optics, cone isomerizations, phototransduction, and mRGC spatial filtering. The model performs a forced choice orientation discrimination task on mRGC responses using a linear support vector machine classifier. The model shows that asymmetries in a decision maker’s performance across polar angle are greater when assessing the photocurrents than when assessing isomerizations and are greater still when assessing mRGC signals. Nonetheless, the polar angle asymmetries of the mRGC outputs are still considerably smaller than those observed from human performance. We conclude that cone isomerizations, phototransduction, and the spatial filtering properties of mRGCs contribute to polar angle performance differences, but that a full account of these differences will entail additional contribution from cortical representations.

Reducing Sexual-Orientation Discrimination: Experimental Evidence from Basic Information Treatments

We study basic information treatments regarding sexual orientation using randomized experiments in three countries with strong and widespread anti-gay attitudes: Serbia, Turkey, and Ukraine. Participants who received information about the economic costs to society of sexual-orientation discrimination were significantly more likely than those in a control group to support equal employment opportunities based on sexual orientation. Information that the World Health Organization (WHO) does not regard homosexuality as a mental illness increased social acceptance of sexual minorities, but only for those who reported trust in the WHO. Our results have important implications for policy makers aiming to expand the rights of lesbian, gay, and bisexual people worldwide.

Where we perceive before we look: The distribution of presaccadic attention assessed with dynamic 1/f noise

Already before the onset of a saccadic eye movement, we preferentially process visual information at the upcoming eye fixation. This 'presaccadic shift of attention' is typically assessed via localized test items, which potentially bias the attention measurement. Here we show how presaccadic attention shapes perception from saccade origin to target when no scene-structuring items are presented. Participants made saccades into a 1/f ('pink') noise field, in which we embedded a brief orientation signal at various locations shortly before saccade onset. Local orientation discrimination performance served as a proxy for the allocation of attention. Results demonstrate that (1) saccades are preceded by shifts of attention to their goal location even if they are directed into an unstructured visual field, but the spread of attention, compared to target-directed saccades, is broad; (2) the presaccadic attention shift is accompanied by considerable attentional costs at the presaccadic eye fixation; (3) objects markedly shape the distribution of presaccadic attention, demonstrating the relevance of an item-free approach for measuring attentional dynamics across the visual field.

The strong global trend of prohibiting employment discrimination based on sexual orientation

Over the last 30 years, more than 85 countries have prohibited sexual orientation discrimination in employment. Enacting such legal prohibitions has thereby become the most common form of legal recognition of homosexual orientation (more so than the decriminalisation of homosexual sex or the opening up of family law to same-sex partners). The trend is global (ten countries in Africa, more in Asia/Oceania, many in Europe and the Americas). The trend is reflected in supranational rules of the European Union and the Organisation of American States and also in decisions of international human rights bodies. On the basis of these numbers and developments, and in light of the various factors that help explain the strength of this global trend, the author argues that it is to be expected that the trend will continue to reach more and more countries. Explicit legal prohibitions of sexual orientation discrimination in employment can play a useful – perhaps central – role amongst other legal, educational, and social strategies aimed at increasing LGB inclusion.

Psychiatric Disorders Mediates the Association between Sexual Orientation Discrimination and Substance Use Disorders among Sexual Minority Adults

Although sexual orientation discrimination (SO-discrimination) is associated with an increased risk of psychiatric and substance use disorders (SUD) among sexual minority (SM) adults, these relationships are not well understood, particularly in the context of SUD severity. To address this gap, we assessed the direct and indirect effect of SO-discrimination and sexual identity on psychiatric disorders and SUD severity in the context of stress and resilience among SM adults. We used data from 3,494 adults reporting nonheterosexual identity, attraction, or behavior collected as part of a nationally representative cross-sectional sample of adults in the United States. Structural equation modeling assessed potential pathways between SO-discrimination, psychiatric disorders, and SUD severity. Past-year psychiatric disorders and SUD severity were significantly correlated in the multivariate model. Concordant homosexual orientation was associated with reduced risk of psychiatric disorders, but not with past-year SUD severity. SO-discrimination was significantly associated with increased risk of psychiatric disorders, but was not a significant predictor of SUD severity. Notably, SO-discrimination was not directly associated with SUD severity, but was found to have a significant indirect effect on SUD severity through psychiatric disorders. SO-discrimination was directly associated with increased risk of psychiatric disorders, and psychiatric disorders mediated the pathway between SO-discrimination and SUD severity. Since psychiatric disorders and SUD are often cooccurring, these data indicate integrated assessment strategies and dual interventions for SM populations.

Ginger Seeding Detection and Shoot Orientation Discrimination Using an Improved YOLOv4-LITE Network

A consistent orientation of ginger shoots when sowing ginger is more conducive to high yields and later harvesting. However, current ginger sowing mainly relies on manual methods, seriously hindering the ginger industry’s development. Existing ginger seeders still require manual assistance in placing ginger seeds to achieve consistent ginger shoot orientation. To address the problem that existing ginger seeders have difficulty in automating seeding and ensuring consistent ginger shoot orientation, this study applies object detection techniques in deep learning to the detection of ginger and proposes a ginger recognition network based on YOLOv4-LITE, which, first, uses MobileNetv2 as the backbone network of the model and, second, adds coordinate attention to MobileNetv2 and uses Do-Conv convolution to replace part of the traditional convolution. After completing the prediction of ginger and ginger shoots, this paper determines ginger shoot orientation by calculating the relative positions of the largest ginger shoot and the ginger. The mean average precision, Params, and giga Flops of the proposed YOLOv4-LITE in the test set reached 98.73%, 47.99 M, and 8.74, respectively. The experimental results show that YOLOv4-LITE achieved ginger seed detection and ginger shoot orientation calculation, and that it provides a technical guarantee for automated ginger seeding.

Time Course of Perceived Visual Distortion and Axial Length Growth in Myopic Children Undergoing Orthokeratology

Purpose: To establish the time course of the subjective visual function changes during the first month of orthokeratology treatment in myopic children, and to investigate how the time course variations are associated with the objective optical quality changes and the axial length growth (ALG) after 1 year of treatment.Methods: A total of 58 myopic children aged from 8 to 16 years participated in this self-controlled prospective study. All subjects were fitted with designed spherical four-zone orthokeratology lenses. Subjective visual function was evaluated with orientation discrimination threshold (ODT), and objective optical quality was quantified with the high-order aberration root-mean-square (HOA-RMS) and the changing speed of HOA. The measurements were done before the lens fitting and 1 day, 1-, 2-, and 4-weeks after lens wear. Axial length was obtained at baseline and 1-year follow-up, and ALG was defined as the difference. One-way ANOVA was conducted to compare the difference for statistical analysis.Results: After lens fitting, the ODT time courses peaked on day 1 in 28 children, 1 week in 15 children, 2 weeks in 11 children, and 4 weeks in 4 children. In contrast, the HOA-RMS steadily rose during the first month, and the changing speed of HOA was only transiently elevated on day 1 after the initial lens wear. The ALG was 0.12 ± 0.20 mm in subjects whose ODT peaked at day 1, 0.08 ± 0.09 mm in subjects whose ODT peaked on 1-week, and 0.12 ± 0.15 mm in subjects whose ODT peaked on 2-week or later. There was no difference in axial growth among the subjects whose ODT peaked at different days (P = 0.734).Conclusion: While half ODT time course resembled the changing speed of HOA with a transient elevation on day 1, about a quarter of the ODT time course resemble the steadily rising of HOA-RMS, and the rest was located in the middle. The ALGs in children with different types of ODT time courses were similar.

Decomposing response times in Williams syndrome in separate cognitive processes

Williams Syndrome (WS) is a rare neurodevelopmental disorder of genetic origin. The syndrome is characterised by a selective set of deficits in a number of cognitive domains. In spite of a wealth of studies, response times (RTs) of WS have attracted little attention. In the present study, we fill this gap by analysing data from a receptive vocabulary task using the Diffusion Decision Model (DDM). Our results show that the speed of accumulation, decision threshold and non-decision time parameters of WS individuals are similar to these of typically developing 5-year-old preschoolers. In addition, WS verbal intelligence scores were associated with the speed of accumulation of lexical information. Finally, the performance of WS and preschooler individuals was correlated across the vocabulary task and an additional orientation discrimination task only at the group but not at the individual level; therefore, pointing to domain-specific lexical and perceptual processing in WS.

Qualitative speed-accuracy tradeoff effects can be explained by a diffusion/fast-guess mixture model

Rafiei and Rahnev (2021) presented an analysis of an experiment in which they manipulated speed-accuracy stress and stimulus contrast in an orientation discrimination task. They argued that the standard diffusion model could not account for the patterns of data their experiment produced. However, their experiment encouraged and produced fast guesses in the higher speed-stress conditions. These fast guesses are responses with chance accuracy and response times (RTs) less than 300 ms. We developed a simple mixture model in which fast guesses were represented by a simple normal distribution with fixed mean and standard deviation and other responses by the standard diffusion process. The model fit the whole pattern of accuracy and RTs as a function of speed/accuracy stress and stimulus contrast, including the sometimes bimodal shapes of RT distributions. In the model, speed-accuracy stress affected some model parameters while stimulus contrast affected a different one showing selective influence. Rafiei and Rahnev’s failure to fit the diffusion model was the result of driving subjects to fast guess in their experiment.