Visuals Sans Vision

Unlocking your other senses for data visualization.

Photo by Ryoji Iwata on Unsplash.

Humankind has been visualizing data for ages. From cave paintings in the Paleolithic Age to complex visualizations of stock market data in the modern age, we have come a long way. But considering the fact that the very basic requirement for an individual to access a visualization is the ability to see, we still have a long way to go before data visualization is accessible and equitable for all.

The number of blind or visually impaired people in the world is estimated to reach around 703 million by 2050. The first step in understanding how visualization can be made accessible to the visually impaired is to understand how visually impaired individuals perceive the world and interact with it. This is the challenge explored by Pramod Chundury et al. in a recent IEEE VIS 2021 paper. To gain insight about blind and visually impaired people, the researchers interviewed 10 Orientation and Mobility (O&M) experts. Orientation and Mobility experts teach blind and visually impaired individuals to navigate the world and become independent. The 10 chosen experts were also blind, hence they have significant experience in navigating a world without sight and are competent in passing on these skills to other blind individuals.

The thought of perceiving the world without sight can be scary for sighted individuals. Hence, the sighted community tends to have inaccurate assumptions of how blind people make sense of their environment. These biases and assumptions can hinder accessible design and can result in poor accessibility considerations for blind individuals. Hence, it is hence of utmost importance to accurately understand their experience so as to pave the way for accessibility.

Image from academic paper “Towards understanding sensory substitution for Accessible visualization: An interview study” by Pramod Chundury et al.

The research analyzed the interviews with O&M experts using thematic analysis to collect several insights. These interview insights can be grouped into the following categories:

1. Perception: O&M experts stress the importance of combining sound and touch in making sense of the world. Blind individuals use several channels of sound such as frequency, loudness, pitch, or even the absence of sound (called sound shadows) to create spatial mappings of their environment. Using these channels, they can determine the distances of objects, sizes of objects, location of objects etc.
2. Interaction: Blind students are taught to think of their white canes as an extension of their body. The canes allow the user to interact with the world using both touch and sound. Tapping the cane in positions respective to their body and listening to the echoes can help them create spatial awareness (echolocation).
3. Effectiveness: The effectiveness of both touch and sound can vary as each has pros and cons depending on the situation. The O&M experts note that touch or haptic feedback is more similar to vision than sound. Touch is also more intuitive than sound and doesn’t require as much training. The downside is that special equipment would be required to create haptic feedback. On the other hand, sound doesn’t require special equipment, but the O&M experts pointed out that a lot of training is required for an individual to pick up the nuances and variations in sound representations of data. In the end, experts agree that a combination of both sound and touch is the way forward to making data visualization accessible to the blind.
4. Challenges: Aside from the inherent challenges in incorporating these sensory substitutes for vision and training blind individuals to hone better control over their other senses to perceive visualization, one main problem is creating visualizations that are accessible to both the sighted and non-sighted community. Creating separate representations for the blind will only increase the gap in understanding and can hinder collaboration. The point of making visualization accessible is to foster collaboration and easy communication between sighted and non-sighted individuals.
5. Design guidelines: Based on the insights from the interview, the researchers have put forward some guidelines for designing accessible visualization. Some examples include retaining the visual structure of existing visualizations, combining the use of sound and haptics, utilizing interaction for non visual sense-making, accessing information in layers to avoid sensory overload, etc. These guidelines involve translating blind individuals’ spatial navigation techniques and mental models while traversing the real world to the context of navigating, understanding, and interacting with representations of data.

In the end, these guidelines will help contribute to the growing body of research trying to make visualization accessible and equitable to everyone.

Creating separate representations for the blind will only increase the gap in understanding.

References

• Chundury, P., Patnaik, B., Reyazuddin, Y., Tang, C., Lazar, J., & Elmqvist, N. (2022). Towards understanding sensory substitution for Accessible visualization: An interview study. IEEE Transactions on Visualization and Computer Graphics, 28(1), 1084–1094. https://doi.org/10.1109/tvcg.2021.3114829