  Data has transformative potential to empower people with Intellectual and
Developmental Disabilities (IDD). However, conventional data visualizations
often rely on complex cognitive processes, and existing approaches for
day-to-day analysis scenarios fail to consider neurodivergent capabilities,
creating barriers for people with IDD to access data and leading to even
further marginalization. We argue that visualizations could be an equalizer for
people with IDD to participate in data-driven conversations. Drawing on
preliminary research findings and our experiences working with people with IDD
and their data, we introduce and expand on the concept of cognitively
accessible visualizations, unpack its meaning and roles in increasing IDD
individuals' access to data, and discuss two immediate research objectives.
Specifically, we argue that cognitively accessible visualizations should
support people with IDD in personal data storytelling for effective
self-advocacy and self-expression, and balance novelty and familiarity in data
design to accommodate cognitive diversity and promote inclusivity.
