Edited by: Elif Özcan, Delft University of Technology, Netherlands
Reviewed by: Anita Zanella, National Institute of Astrophysics (INAF), Italy
Phia Damsma, Sonokids Australia, Australia
Lucrezia Guiotto Nai Fovino, University of Padua, Italy
†These authors have contributed equally to this work
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Historically, astronomy has prioritized visuals to present information, with scientists and communicators overlooking the critical need to communicate astrophysics with blind or low-vision audiences and provide novel channels for sighted audiences to process scientific information.
This study sonified NASA data of three astronomical objects presented as aural visualizations, then surveyed blind or low-vision and sighted individuals to elicit feedback on the experience of these pieces as it relates to enjoyment, education, and trust of the scientific data.
Data analyses from 3,184 sighted or blind or low-vision survey participants yielded significant self-reported learning gains and positive experiential responses.
Results showed that astrophysical data engaging multiple senses could establish additional avenues of trust, increase access, and promote awareness of accessibility in sighted and blind or low-vision communities.
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Light is the dominant data source in the Universe; therefore, our sense of sight pervades historical astronomy. For millennia, humans explored the sky with the unaided eye until the invention of the telescope (1608) provided a deeper view of the cosmos. In 1851, the first daguerreotype of a Solar eclipse captured the Sun's light, the first astronomical image (
First image of the Sun, taken in Fizeau and Foucault (
Newly launched space-based observatories captured many of these large data sets, which revolutionizing astronomy's cultural impact (Taterewicz,
In the late twentieth century, CCDs began to specialize, observing and transposing light outside visible wavelengths, extending the observable Universe once more. Here, data visualization became essential. NASA's “Great Observatories” [originally the Hubble Space Telescope, Compton Gamma Ray Observatory, Chandra X-ray Observatory, and Spitzer Space Telescope (National Aeronautics and Space Administration,
Image aesthetics is essential in aiding data comprehension (Arcand et al.,
Studies on astronomical image processing (Rector et al.,
Sonification is often defined as mapping data to sound to represent information using non-speech audio, the sonic counterpart to visualization (Kramer et al.,
In recent years, sonification has become more present in the world of astronomy as communicators and researchers alike try to understand how best to engage the BLV community and allow astronomers to conduct their research using sound alone; see Harrison et al. (
The most common approaches to sonification are audification and parameter mapping. With audification, data are translated and mapped directly to audio, so the relevant frequencies fall within hearing range; for example, the sonification of gravitational wave signals recorded by the Laser Interferometer Gravitational-Wave Observatory (LIGO) collaboration (Abbot,
For parameter mapping, aspects of the data control specific audio parameters. For example, a star's brightness fluctuations or hues of color may control the frequency so that unique features can be identified (Astronify,
Sonification provides astronomy communicators a new avenue to engage the public, particularly BLV communities, traditionally excluded from engagement. Furthermore, sonification is advantageous as a research tool (with or without visually presented information) because listening to data exploits the auditory system's exquisite sensitivity to pattern variation over time, whether perceived as discrete rhythms or changing pitch (Walker and Nees,
In recent years, NASA has released several sonification projects, showcasing several decades of data (National Aeronautics and Space Administration,
Before we discuss the results of our work, it is essential to acknowledge our positionality within the context of this study. For some authors, our motivation to explore this topic is shaped by a personal connection to the disability community through lived experience (either in the BLV community or the broader disability community); for others, the motivation lies in the desire to explore alternate data vivification processes and understand how to communicate science to the public effectively. Our own experiences have led us to believe sonification is a positive tool for education and research, and we remain mindful of this bias throughout our analysis. Finally, although our team represents a range of perspectives within the disability and astronomy community, we acknowledge that we remain limited by our lived experiences as a group of majority white individuals living in North America and Canada.
The primary research questions for this study were:
How are data sonifications perceived by the general population and members of the BLV community?
How do data sonifications affect participant learning, enjoyment, and exploration of astronomy?
There were two secondary research questions:
Can translating scientific data into sound help enable trust or investment, emotionally or intellectually, in scientific data?
Can such sonifications help improve awareness of accessibility needs that others might have?
The research participants were a convenience sample of respondents (18 years and older) to an online survey. We solicited participants from websites including Chandra
The Smithsonian Institutional Review Board
We chose three sonifications from the six available at the time of the study at NASA's Universe of Sound website, choosing those that best represent the collection available for their variation of instrumental vs. synthetic sounds and how they track the visual data—left to right, top to bottom, or radially. Survey participants were presented with the sonifications and their accompanying videos to experience as they were able, followed by short text descriptions (screen-reader adaptable) for each of the represented astronomical objects (the Galactic Center, Cassiopeia A, and the Chandra Deep Field South). The sonifications played in the same order, without counterbalancing, starting with the sonification that used non-synthesized sounds, followed by two more complex sonifications. We provide the details of each sonification at the companion GitHub
Each row in the table describes the basic parameters for each sonification including a link to the data product, the runtime (in suitable units), the types of sounds used, the number of individual components in the sonification, the wavelength range sonified, and the communication goal of the sonification when it was created.
Galactic Center ( |
1.04 min per piece. Total Time: 4.16 min | Instruments: Glockenspiel, String, Piano. | 4 Three individual, one composite. | X-ray (Chandra), Optical (Hubble), Infrared (Spitzer). | Left to right | Communicating detectable structures in different wavelength regimes and highlighting the high density and activity that is present near the Galactic Center. |
Cassiopeia A ( |
42 s for the first five. 21 s for the sixth. Total Time: 3.52 min | Instruments: String section (double bass, cello, viola, and two violins) | 6 Five individual, one composite. | X-ray (by elemental abundance). | Radial—from the center outwards on four paths. | Revealing the chemical emissions throughout the debris field and highlighting the remnant's shape and structure. |
Chandra Deep Field South ( |
Total Time: 48 s | Synthetic sounds | 1 | X-ray (by low, medium, high energies). | Bottom to top | Demonstrating the extensive range of X-ray energies/frequencies and demonstrating black hole number density. |
Our survey began with five demographic questions
Participants were then asked to experience the sonifications and after each, respond to a set of statements using a Likert scale. Each statement began with:
“
The five statements were:
I enjoyed this experience.
I learned more about the [title of sonification, i.e., Galactic Center] through this experience.
Hearing the sounds enhanced my experience.
Watching the videos enhanced my experience (if applicable).
I trust that this representation is faithful to the science data.
The scale provided the following options: 1 (Disagree Strongly), 2 (Disagree), 3 (Neutral), 4 (Agree), 5 (Agree Strongly).
Following this section, the participants were asked about their overall experience, first:
“
Then, they were asked to rate the following three statements, using the same Likert scale from the first section:
Finally, they were asked two open-ended questions (which allowed for full sentences). These were:
Once the survey closed, we exported the data and cleaned and analyzed the 4,346 responses using Python. We removed the entry of one participant who took from March until July 2021 to complete the survey and all responses in which participants did not indicate whether they were BLV or sighted or answered fewer than three non-demographic questions. This cleaning ensured we could compare the results of the BLV and sighted groups for those who engaged with the sonification questions. We removed identical entries by comparing Internet Protocol (IP) addresses and demographic questions. For repeat entries, we kept only the most recent response. Cleaning yielded 3,184 participant responses. See the
Histogram showing the relative amount of BLV and sighted participants. Red (blue) bars represent sighted (BLV) participants. The x-axis shows the participant counts and the y-axis shows the self-reported level of astronomy knowledge from novice to expert. Note the significant difference between BLV and sighted participants. Thirteen participants omitted astronomical knowledge or BLV status and were omitted from this figure.
Regarding additional demographics, we note a slight majority of male-identifying participants (57.1%). Participant ages spanned from 18 to 24 years (21.6%) to 65 years and older (16.3%); there is a slight predominance of younger participants, but all age groups are represented at above 10% of the total. Likewise, the self-reported education level of participants ranges from those who completed some of high school to those with advanced postgraduate degrees (i.e., doctorate, LLB, or MD); however, those who completed some of high school were the least represented group (3.5%), with most participants (61.3%) having completed an undergraduate degree or higher. We refer the reader to the tables in the
These histograms depict the participant's ratings of their enjoyment of each sonification. A rating of one represents the least enjoyment (Disagree Strongly), and five represents the most amount of enjoyment (Agree Strongly). We normalized the histograms for easier comparison between the sighted and BLV groups due to the significant difference in sample size. Blue histograms represent the sighted group, and the black hatched histograms represent the BLV group.
K-S test statistics and
Galactic Center | 0.0343 | 0.9767 |
Cassiopeia A | 0.0625 | 0.6227 |
Deep Field | 0.0094 | 1.0 |
Galactic Center | 0.0812 | 0.1664 |
Cassiopeia A | 0.1249 | |
Deep Field | 0.1063 | 0.0915 |
Galactic Center | 0.0662 | 0.3183 |
Cassiopeia A | 0.0704 | 0.4786 |
Deep Field | 0.0239 | 1.0 |
Galactic Center | 0.0616 | 0.5067 |
Cassiopeia A | 0.0261 | 1.0 |
Deep Field | 0.0177 | 1.0 |
Galactic Center | 0.0390 | 0.9315 |
Cassiopeia A | 0.0284 | 0.9998 |
Deep Field | 0.0275 | 0.9999 |
After listening to these data sonifications, I am motivated to listen to more. | 0.0966 | 0.2156 |
After listening to these data sonifications, I am interested in learning more about our Universe. | 0.1258 | |
After listening to these data sonifications, I want to learn more about how others access information about the Universe. | 0.1313 |
Bold
Ratings for the prompt: “I learned more about the [title of sonification, i.e., Galactic Center] through this experience,” are shown in
These histograms depict the participants' feelings on how much they learned from each sonification. Unless otherwise stated, these and all subsequent histograms follow the same conventions as
These histograms depict the participants' agreement on whether their experience of the images was enhanced by adding sound.
The responses to the prompt “Watching the video enhanced my experience” are depicted in
These histograms depict the participants' rating of whether their experience was enhanced by watching the included video.
The prompt: “I trust that this representation is faithful to the science data,” is displayed in
These histograms depict the participants' agreement on whether they trusted the sonifications were scientifically accurate.
These histograms depict ratings for three prompts provided after participants had listened to all sonifications.
The distribution of ratings regarding interest in continued learning about the Universe and how others access this information differed significantly between the groups (
This word cloud shows words provided by participants when asked to describe the sonifications. Larger words correspond to those used more frequently.
The first open-ended question asked, “What recommendations do you have to help the scientific community create better listening experiences?” There were no character limits imposed on the answers. Using manual inductive coding (Chandra and Shang,
Amongst the responses, we noted two frequent themes; the first, a common misunderstanding of sonification, both at its conceptual level (e.g., “Include actual sound from space”) and in the context of interpretation (e.g., “I don't fully understand the relationship between the sounds and what we are seeing”). These comments suggest an unfamiliarity with sonification as a form of data representation, and the audience may require more background to interpret this representation correctly. We teach students to read graphs and charts visually, so education in sonification might likewise be necessary, echoing the suggestions of Fleming (
The second theme noted is the frequent suggestions regarding the assignment of pitches and other audio parameters to the data, ranging from musical suggestions (e.g., “Please don't stick to the equal temperament system in sound reproduction, so much scientific information is lost or misrepresented that way. Also, why link different things to different pitches suggesting differences in quality better represented by different timbre?”) to responses tagged as scientific (e.g., “If you're going to assign a sonification to individual elements, I think you're going to have to find a better way to differentiate between them than to just change the note on the scale. Maybe brainstorm a way to differentiate between them based on atomic weight or outer electron shell, assigning a sonification to the sounds the orbits might make.”). These responses reflect the question of standardization in sonification, much the same as the standards for visual data representation: how we represent different images or data types in a way that is both interpretable across different sonifications and auditorily pleasant. These standards could improve the feasibility of sonification education.
The second open-ended question asked, “If the person who created these data sonifications were here, what question would you ask them?” We coded these responses into the same seven categories. There were 1,656 responses after removing non-descriptive responses. Across the categories, many questions involved the purpose of these sonifications (e.g., “is the goal enchanting soundscapes or information transfer or enhancing information acquisition in non-visual.” and “By a glimpse to photo we can all have these information at once. So what is the use of this?”). Other questions inquired how the audio parameters were mapped to the image data (e.g., “Did you select the frequency distributions to try and make the sonifications tuneful, or are they evenly (linearly, logarithmically) spaced across the audio spectrum?”). The ubiquity of these questions indicates the relative novelty of and lack of familiarity with sonification as a data representation tool among general audiences.
Participants across both groups rated their experience as enjoyable (
Surprisingly, the Deep Field showed the widest range of enjoyment, which was unexpected as we reduced the image resolution by a factor of four before being sonified to produce more audible, consistent tones. We made this change to add musical regularity, designed to increase enjoyment. This sonification may have been the least popular as it was the shortest and contains synthetic sounds. Considering this alongside the first open-ended question, which demonstrates participant preference for orchestral sounds, a preference for instrumental sonifications could be demonstrated. In addition, demographic information may be pertinent here; for example, do particular listeners prefer orchestral sounds?
The BLV participants reported learning more than the sighted participants (
Many participants felt that the sonifications represented scientifically accurate data (
The BLV participants wanted to listen to further sonifications, learn more about the process, and learn more about how others access information about the Universe (
With the exception of the self-reported learning from the Cassiopeia A sonification (
Responses to our first open-ended question regarding possible improvement (Section 6.1) revealed two potential misunderstandings. The first misconception is the source of the sound (i.e., the sounds are only representations of the data), which is rectifiable with better explanations of the sonification process. Similar misconceptions may also affect visually represented data, for example, the translation of X-ray data to visually accessible images, where the viewer might conclude that these celestial objects are visible to the human eye (Varano and Zanella,
This study represents a valuable contribution to accessibility in astronomy; however, it is not as rigorous as desired. We selected participants via a convenience sample, where they voluntarily chose to complete our survey after receiving the link from a newsletter (Chandra or APOD) or astronomy-related social media account. Due to the voluntary nature of participation, those involved may be more interested in astronomy and have a base of knowledge, possibly affecting their interpretation of the sonifications. By formulating a questionnaire that (in part) attempts to obtain opinions on sonification products produced by the authors, we may have introduced a social desirability bias, potentially causing participants to respond more favorably to the sonifications. A complete analysis of this effect is outside this work's scope, but we may consider it more thoroughly in future publications.
Our most significant limitation was the lack of BLV respondents, with the smaller sample size resulting in increased uncertainty in the distribution of their responses. Finally, our survey includes a United States-heavy participant distribution due to how we circulated the survey.
Scientists, data processors, and science communicators are failing to reach and communicate with BLV audiences. We should expand our priorities for processing and presenting information beyond images and present new, novel methods for those with and without sight loss to engage with science. The public availability of astronomy data does not necessarily equate to the true accessibility and equity of that data, much as providing a sidewalk in a high-traffic area improves pedestrian safety but remains inherently inaccessible and inequitable without thoughtful design (by cutting the curb). This paper offers suggestions on potential means for universal design for learning (Bernacchio and Mullen,
Translating data into sonifications is similar to translating language; by considering cultural nuance, we can create sounds that retain astronomical information and impart an accessible mode for scientific communication. A key conclusion is that the sighted participants enjoyed, learned, and had their experience of astronomy enhanced by the sonifications to similar levels as the BLV participants. The responses from the BLV community reinforce the need for access, and the responses from the sighted community show the benefit to all. These results are typical when implementing accessible designs. For example, consider moving airport walkways, a requirement of the Americans with Disabilities Act
Furthermore, when considering our secondary research question, “Can translating scientific data into sound help enable trust or investment, emotionally or intellectually, in scientific data?” we urgently need accessible data to improve trust.
The secondary research question, “Can such sonifications help improve awareness of accessibility needs that others might have?” was explored in
As we progress from this work, the long-term potential learning gains for respondents who engage with sonified data is an important consideration. A single exposure to our sonifications and related questions cannot quantify the long-term learning outcomes of the participants; however, this is an important consideration when implementing sonified materials into more formal educational settings, and it is essential to examine whether using multiple methods would reinforce learning outcomes and retention for students.
One more minor but no less critical conclusion is that participants prefer instrumental sonifications over synthesized sounds. This result is significant because the enjoyment and enrichment of the listener is predicated on the listenership, dictated by how many people listen or include sonifications in their communication efforts. Accessibility to astronomy and scientific data, generally, is still in its infancy. Astronomers need an accelerated effort with adequate resources to reach underserved populations. This project is an important step, but many more are needed.
Future work must focus on the active engagement of BLV participants while recognizing and accommodating the wide range of visual impairments within this non-homogenous group. Efforts could employ different sampling techniques to recruit a larger sample, particularly for a range of BLV individuals with a scope of astronomy familiarity. BLV participants without astronomy familiarity provide insight into how intuitive sonifications are, whereas participants with more familiarity can share how well sonifications match or enhance their understanding of the objects.
We acknowledge that the BLV category spans a broad range of sight loss that this study does not explore or quantify. Future research should ask participants to comment on the usefulness of the images accompanying the sonification as a proxy for measuring their functional vision. Researchers could also collect data on the accessibility software used while completing the survey (e.g., screen magnification, screen readers, Braille displays, and other methods) to understand whether BLV participants access the survey visually or often visually access their computers. Furthermore, one could ask for feedback regarding the visualizations to improve the accessibility of these data representations to those with low vision.
Astronomy communicators must continue to address and resolve misunderstandings of the sonification process by improving accompanying descriptions of the techniques used. These updates must consider the lens of trust in science and be mindful of creating minimal opportunities for miscommunication. To understand this better, we must capture data on the number of times a participant plays a sonification, providing a more objective measure of comprehensibility, intuitiveness, enjoyment, and a desire to understand.
Further studies could gauge the self-reported knowledge of music and technology. Many participants gave feedback on the musical quality, indicating an understanding of music theory, and many also gave technical feedback (bearing in mind that some technical proficiency is required to access the survey).
Although we collected participants' ages, we did so primarily to compare the representativeness of our sample to the overall U.S. population (see Table 3 in the
Finally, this work could extend to investigate actual learning outcomes, as opposed to self-reported learning (as in this study). However, this is outside this paper's scope and would involve a participant and control group learning with and without access to sonification.
Input from the broader community is invaluable, and we are encouraged by the recommendations received and excited to implement them into new work. We look forward to collaborating with others throughout astronomy and related fields to make as much data available to as many people as possible. Additional resources are available for this paper on a companion GitHub (see text footnote
The original contributions presented in the study are included in the article/
The studies involving humans were approved by Smithsonian Institutional Review Board. The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study, by way of a consent form at the beginning of the survey.
KA: Writing—original draft, Writing—review & editing. JS-S: Writing—original draft, Writing—review & editing. SK: Writing—original draft, Writing—review & editing. GS: Writing—original draft, Writing—review & editing. MR: Writing—original draft. MW: Writing—original draft. BH: Writing—original draft. LS: Writing—review & editing.
The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This paper was written with funding from NASA under contract NAS8-03060 with the principal investigator working for the Chandra X-ray Observatory. NASA's Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science and flight operations from Cambridge and Burlington, Massachusetts. Additional support for the sonifications came from NASA's Universe of Learning (UoL). UoL materials are based upon work supported by NASA under award number NNX16AC65A to the Space Telescope Science Institute, with Caltech/IPAC, Jet Propulsion Laboratory, and the Smithsonian Astrophysical Observatory.
The authors gratefully acknowledge their colleagues at the Center for Astrophysics, NASA and particularly NASA's Astronomy Picture of the Day, for their gracious dissemination help with the study. JS-S acknowledges the Frist Center for Autism and Innovation in the School of Engineering at Vanderbilt University, who fund the Neurodiversity Inspired Science and Engineering Graduate Fellowship. SK acknowledges the Marshall Scholarship.
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.
The Supplementary Material for this article can be found online at:
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11Breakdowns of demographic information collected for the survey can be found in the
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15Americans With Disabilities Act of 1990, Pub. L. No. 101-336, 104 Stat. 328 (1990).
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