Simulated central vision loss impairs implicit location probability learning

Abstract

Some eye diseases, especially macular degeneration, can cause central vision loss (CVL), impairing goal-driven guidance of attention. Does CVL also affect implicit, experience-driven attention? We investigated how simulated central scotomas affected young adults' ability to prioritize locations frequently containing visual search targets (location probability learning). Participants searched among distractor letter 'L's for a target 'T' that appeared more often in one screen quadrant than others. To dissociate potential impairments to statistical learning of target locations and attentional guidance, two experiments each included search with and without simulated scotomas. Experiment 1 successfully induced probability learning in a no scotoma phase. When participants later searched both with and without simulated scotomas, they showed persistent, statistically equivalent spatial biases in both no-scotoma and scotoma search. Experiment 2 trained participants with a central scotoma. While Experiment 1's participants acquired probability learning regardless of their self-reported awareness of the target's location probability, in Experiment 2 only aware participants learned to bias attention to the high probability region. Similarly, learning with a scotoma affected search with no scotoma in aware but not unaware participants. Together, these results show that simulated central vision loss interferes with the acquisition of implicitly learned location probability learning, supporting a role of central vision in implicit spatial attentional biases.

Simulated central vision loss does not impair implicit location probability learning when participants search through simple displays

“…Participants were between 18 and 45 with normal or corrected-to-normal visual acuity and no reported visual field loss. We initially planned to recruit data from 24 participants, the sample size used in Addleman et al (2021). Data collection was halted early due to COVID-19, resulting in a dataset of 16 participants: 13 women and 3 men, with a mean age of 21 (range: 18-31).…”

“…Based on effect sizes from Addleman et al (2021), power to detect location probability learning at an alpha level of .05 is still high with 16 participants: nearly 100% to detect learning in the training phase and 99% to detect persistence into the testing phase. This study was approved by the University of Minnesota Institutional Review board and all participants provided informed consent.…”

“…This strategy has been used to investigate how central vision loss affects not only voluntary control of attention (as when someone intentionally guides their search to where they thought they put their keys) but also the implicit effects of experience on attention (as when attention is involuntarily biased towards places where keys were often found). These implicit influences on attention may play major roles in guiding everyday search behavior (Awh et al, 2012;Jiang, 2018) and may compensate for deficits in goal-driven attention in clinical populations (e.g., due to Autism Spectrum Disorders, Parkinson's, or central vision loss; Addleman et al, 2021;Jiang, Capistrano, et al, 2013;Sisk et al, 2018). Thus, recent research has focused on investigating the effects of central vision loss on implicit attention (Addleman et al, 2021;Geringswald & Pollmann, 2015;Pollmann et al, 2020).…”

“…For example, we reported how simulated central vision loss impaired the acquisition of attentional biases via location probability learning (Addleman et al, 2021). Participants searched for a target among distractors overlaid on a natural scene image, both with and without a simulated central scotoma.…”

“…We conducted two experiments investigating the effects of simulated central vision loss on location probability learning in visual search for simple stimuli, modeled after our experiments using natural scenes (Addleman et al, 2021). In both experiments, participants searched for a white T among white Ls on a uniform black background.…”