Monocular discs in the occlusion zones of binocular surfaces do not have quantitative depth--a comparison with Panum's limiting case

Da Vinci stereopsis is defined as apparent depth seen in a monocular object laterally adjacent to a binocular surface in a position consistent with its occlusion by the other eye. It is widely regarded as a new form of quantitative stereopsis because the depth seen is quantitatively related to the lateral separation of the monocular element and the binocular surface (Nakayama and Shimojo 1990 Vision Research 30 1811-1825). This can be predicted on the basis that the more separated the monocular element is from the surface the greater its minimum depth behind the surface would have to be to account for its monocular occlusion. Supporting evidence, however, has used narrow bars as the monocular elements, raising the possibility that quantitative depth as a function of separation could be attributable to Panum's limiting case (double fusion) rather than to a new form of stereopsis. We compared the depth performance of monocular objects fusible with the edge of the surface in the contralateral eye (lines) and non-fusible objects (disks) and found that, although the fusible objects showed highly quantitative depth, the disks did not, appearing behind the surface to the same degree at all separations from it. These findings indicate that, although there is a crude sense of depth for discrete monocular objects placed in a valid position for uniocular occlusion, depth is not quantitative. They also indicate that Panum's limiting case is not, as has sometimes been claimed, itself a case of da Vinci stereopsis since fusibility is a critical factor for seeing quantitative depth in discrete monocular objects relative to a binocular surface.     

Visual acuity improvement following fading and feedback training—I. Comparison of myopic and emmetropic volunteers

18 myopes and 18 emmetropes were randomly assigned in pairs to either Fading and Feedback training or a no-treatment control condition. The emmetropes were fitted with plus lenses equivalent to the spherical correction of the paired myope to simulate myopic visual acuity. Extensive visual acuity measures were obtained pre- and post-training. Data analyses indicated significant increases in recognition visual acuity for trained subjects, compared to no-treatment controls. The myopia/emmetropia variable did not interact with training even though there were noticably greater increases in visual acuity for trained myopes compared to the other conditions. Resolution visual acuity did not change as a function of training. These data are discussed in terms of their implications for better understanding the mechanisms responsible for visual acuity increases following behavioural training.     

Does partisan media make a pawn of mistrust? Institutional trust and preventive COVID-19 health behaviors in a polarized pandemic

In a rapidly developing crisis such as the COVID-19 pandemic, people are often faced with contradictory or changing information and must determine what sources to trust. Across five time points (N = 5902) we examine how trust in various sources predicts COVID-19 health behaviors. Trust in experts and national news predicted more engagement with most health behaviors from April 2020 to March 2022 and trust in Fox news, which often positioned itself as counter to the mainstream on COVID-19, predicted less engagement. However, we also examined a particular public health behavior (masking) before and after the CDC announcement recommending masks on 3 April 2020 (which reversed earlier expert advice discouraging masks for the general public). Prior to the announcement, trust in experts predicted less mask-wearing while trust in Fox News predicted more. These relationships disappeared in the next 4 days following the announcement and reversed in the 2 years that follow, and emerged for vaccination in the later time points. We also examine how the media trusted by Democrats and Republicans predicts trust in experts and in turn health behaviors. Broadly we consider how the increasingly fragmented epistemic environment has implications for polarization on matters of public health.     

Preference for leisure items over edible items in individuals with dementia: A replication

We replicated previous research in which adults with dementia tended to show a preference for leisure items over edible items when presented in the same array. Additionally, we conducted engagement analyses with the highest, middle, and lowest preference leisure items to determine whether relative preference corresponded to engagement in the natural environment. The most highly preferred stimulus for 6 out of 7 participants was a leisure item, and for each of those six the top 3 preferred stimuli were leisure stimuli. For 4 participants, the most preferred stimulus also produced the longest duration of engagement. We discuss the issues we encountered when conducting preference assessments with adults with intact vocal verbal repertoires, and suggest potential explanations for the displacement of edibles by leisure stimuli in older adults with dementia.     

Neurocognitive sequelae of pediatric sickle cell disease: a review of the literature.

This literature review summarizes all studies relating neuropsychological performance to neuroimaging findings in pediatric sickle cell disease (N=28; published 1991-2005). Although inconsistencies exist within and across domains, deficits in intelligence (IQ), attention and executive functions, memory, language, visuomotor abilities, and academic achievement have been identified. Overall neurocognitive compromise was revealed to be related to the level of neurological injury and the location of silent infarct. Attentional and executive dysfunction is prevalent and related to frontal lobe abnormalities.