Role of stereopsis losses in older adults’ performance on the fine-grain movement illusion task

Accurate motion perception is necessary for older adults to safely navigate their environments. Yet it is not clear how stereopsis losses contribute to findings of motion perception deficits in older adults. To assess the contribution of stereopsis losses, three groups (younger adults, older adults with intact stereopsis, older adults with poor stereopsis) were recruited for a fine-grain movement task. The distance participants perceived a dot to move across a computer screen was assessed using a staircase procedure. While all participants perceived the dot to move further than the actual distance, older adults with poor stereopsis showed more exaggeration in their estimates than younger adults and older adults with intact stereopsis. However, the groups did not differ in the intraindividual variability of their estimates. These results suggest stereopsis losses in the context of aging may signal neural or oculomotor changes that result in reduced accuracy of positional perception.

Role of stereopsis losses in older adults’ performance on the fine-grain movement illusion task

Accurate motion perception is necessary for older adults to safely navigate their environments. Yet it is not clear how stereopsis losses contribute to findings of motion perception deficits in older adults. To assess the contribution of stereopsis losses, three groups (younger adults, older adults with intact stereopsis, older adults with poor stereopsis) were recruited for a fine-grain movement task. The distance participants perceived a dot to move across a computer screen was assessed using a staircase procedure. While all participants perceived the dot to move further than the actual distance, older adults with poor stereopsis showed more exaggeration in their estimates than younger adults and older adults with intact stereopsis. However, the groups did not differ in the intraindividual variability of their estimates. These results suggest stereopsis losses in the context of aging may signal neural or oculomotor changes that result in reduced accuracy of positional perception.

Perceptual Proxies of Visual Comparison

Perceptual tasks in visualizations often involve comparisons. Of two sets of values depicted in two charts, which set had values that were the highest overall? Which had the widest range? Prior empirical work found that the performance on different visual comparison tasks (e.g., “biggest delta”, “biggest correlation”) varied widely across different combinations of marks and spatial arrangements. In this paper, we expand upon these combinations in an empirical evaluation of two new comparison tasks: the“biggest mean” and “biggest range” between two sets of values. We used a staircase procedure to titrate the difficulty of the data comparison to assess which arrangements produced the most precise comparisons for each task. We find visual comparisons of biggest mean and biggest range are supported by some chart arrangements more than others, and that this pattern is substantially different from the pattern for other tasks. To synthesize these dissonant findings, we argue that we must understand which features of a visualization are actually used by the human visual system to solve a given task. We call these perceptual proxies. For example, when comparing the means of two bar charts, the visual system might use a “Mean length” proxy that isolates the actual lengths of the bars and then constructs a true average across these lengths. Alternatively, it might use a “Hull Area” proxy that perceives an implied hull bounded by the bars of each chart and then compares the areas of these hulls. We propose a series of potential proxies across different tasks, marks, and spatial arrangements. Simple models of these proxies can be empirically evaluated for their explanatory power by matching their performance to human performance across these marks, arrangements, and tasks. We use this process to highlight candidates for perceptual proxies that might scale more broadly to explain performance in visual comparison.

Spatial Frequency Thresholds for Detecting Latent Facial Signals of Threat

This study examined whether latent facial signals of threat can be detected at more extreme ranges of spatial frequencies (SFs), and thus with fewer frequencies from an optimal middle band for face identification, compared with latent nonthreatening facial signals. Using an adaptive staircase procedure and a two-interval forced-choice same-different task, SF thresholds from the lower and higher ends of the SF spectrum were obtained for nonexpressive threatening and nonthreatening faces. Threatening faces were discriminated from neutral faces more quickly and accurately, and engendered more extreme SF thresholds, compared with nonthreatening faces. The results indicate that the components of latent threatening facial signals can be detected under a greater degree of impoverished visual information for face processing compared with their nonthreatening counterparts.

Evaluating Two Ways to Train Sensitivity to Echoes to Improve Echolocation

We investigated whether training sighted individuals to attend to information in echoes could improve their active echolocation ability. We evaluated two training techniques that involved artificially generated sounds. Both artificial techniques were evaluated by their effect on natural echolocation of real objects with self-generated clicks. One group trained by discriminating sounds presented over headphones in the lab. The lateral displacement or distance of the echo was varied in a staircase procedure. The second training group used an echolocation app on a smartphone. They navigated a maze by using echo cues presented over earbuds. The echo cues had 3D audio virtual reality cues. Participants in the control condition did not improve but the majority of participants who trained did improve. The lab training is labor intensive whereas the app training was self-guided and convenient. This has implications for training methods aimed at echolocation that might ultimately be useful for navigation by visually impaired individuals.

Measuring Glance Legibility of Wearable Heads-Up Display Interfaces Using an Adaptive Staircase Procedure

Heads-up displays (HUDs) are growing in popularity and utility, providing novel ways to interact with environments and other individuals. HUD interfaces must allow users to quickly view information without distracting them from their primary task. We test the use of an adaptive staircase as a method to investigate the glance legibility of two Google Glass heads-up display interfaces. Glance legibility refers to an interface’s legibility when viewed in short amounts of time (also known as glance-like conditions). We measure glance legibility by the minimum presentation time required to read an interface and respond correctly to a yes-no question. The applications of this research can help inform the design and evaluation of future heads-up display interfaces under glance-like conditions.