Attitude networks as intergroup realities: Using network-modelling to research attitude-identity relationships in polarized political contexts.

We apply a newly developed attitude network-modelling technique (Response-Item Network, or ResIN) to study attitude-identity relationships in the context of hot-button issues that polarize the current US-American electorate. The properties of the network-method allow us to simultaneously depict differences in the structural organization of attitudes between groups and to explore the relevance of organized attitude-systems for group identity management. Individuals based on a sample of US-American crowd workers (N = 396) and the representative 2020 ANES data set (N = 8280), we model an attitude network with two conflictive partisan belief-systems. In the first step, we demonstrate that the structural properties of the attitude-network provide substantial information about latent partisan identities, thereby revealing which attitudes 'belong' to specific groups. In a second step, we evaluate the potential of attitudes to communicate identity-relevant information. Results from a vignette study suggest that people rely on their mental representations of attitude-identity links to structure and evaluate their social environment. By highlighting functional interdependences between (macro level) attitude structures and identity management, the presented findings help advancing the understanding of attitude-identity dynamics and socio-political cleavages.

Mapping the global opinion space to explain anti-vaccine attraction.

Vaccines save millions of lives every year. They are recommended by experts, trusted by the majority of people, and promoted by expensive health campaigns. Even so, people with neutral attitudes are more persuaded by people holding anti-vaccine than pro-vaccine attitudes. Our analysis of vaccine-related attitudes in more than 140 countries makes sense of this paradox by including approaches from social influence. Specifically, we show that neutral people are positioned closer to anti- than to pro-vaccine people in the opinion space, and therefore more persuadable by them. We use dynamic social simulations seeded with vaccine survey data, to show how this effect results in a drift towards anti-vaccine opinions. Linking this analysis to data from two other multi-country datasets, we found that countries in which the pro-vaccine people are less associated to the neutrals (and so less able to influence them) exhibit lower vaccination rates and stronger increase in distrust. We conclude our paper by showing how taking social influence into account in vaccine-related policy-making can possibly reduce waves of distrust towards vaccination.

Effect of backscattering in phase contrast imaging of the retina.

The observation of retinal cellular structures is fundamental to the understanding of eye pathologies. However, except for rods and cones, most of the retinal microstructures are weakly reflective and thus difficult to image with state of the art reflective optical imaging techniques such as optical coherence tomography. Recently, we demonstrated the possibility of obtaining the phase contrast of retinal cells in the eye using oblique illumination of the retina. Indeed, by illuminating the eye with incoherent oblique illumination, we obtain a secondary oblique illumination from the backscattered light which can then be used to obtain phase contrast in an effective transmission-like configuration. In this technique, a weak phase signal is modulated over an intense background. Maximizing this phase contrast is thus crucial for the image quality. Here, we investigate the parameters that affect phase contrast by modelling image formation with the backscattered light. We find that the key parameter for maximizing contrast is the intensity profile of the backscattered light. Specifically, the gradient of the profile is found to be proportional to the phase contrast. We validate the model by comparing simulations with experimental results on ex-vivo retina samples.

See-through ophthalmoscope for retinal imaging.

With the miniaturization of scanning mirrors and the emergence of wearable health monitoring, an intriguing step is to investigate the potential of a laser scanning ophthalmoscope (LSO) for retinal imaging with wearable glasses. In addition to providing morphological information of the retina, such as vasculature, LSO images could also be used to provide information on general health conditions. A compact eyeglass with LSO capability would give access, on demand, to retinal parameters without disturbing the subject's activity. One of the main challenges in this field is the creation of a device that does not interrupt the user's field of view. We report, to our knowledge, the first see-through ophthalmoscope. The system is analyzed with three-dimensional simulations and tested in a proof-of-concept setup with the same key parameters of a wearable device. Finally, image quality is analyzed by acquiring images of an ex-vivo human eye sample.