UNIVERSITY PARK, Pa. — Voice assistants (VAs) like Alexa and Siri continue to gain popularity in households and on personal devices. According to digital trends research company Emarketer, the number of VA users will surpass 150 million in 2025. Despite the ubiquity, companies haven’t been able to work around users’ strong negative reactions to advertising on these applications. A research team, including scholars from Penn State, may have a solution — they found that giving users more sense of control through a combination of methods reduced negative reactions to advertising messages.

Published in the Journal of Interactive Marketing, the study explored solutions to negative reactions or resistance to advertising, called “ad reactance,” by examining ways to tailor the information users receive from VAs.

No technique had a significant impact on its own. However, the researchers found that a combination of techniques helped users feel more in control and less irritated with ads. For instance, allowing users to choose ad topics reduced ad reactance, but only when users were  not informed of other ad personalization services employed. The results provide practical insights for advertisers to integrate advertising into VAs while preserving user agency and privacy, according to the researchers.

"Clearly this was a situation where advertising is not going to be slipped in, like you do with a regular Google search or with Facebook feeds,” said co-author S. Shyam Sundar, Evan Pugh University Professor and the James P. Jimirro Professor of Media Effects at Penn State’s Donald P. Bellisario College of Communications. “But rather, you need to get users’ buy-in."

The researchers led an experiment with 405 participants. Using a web-based survey, the researchers investigated possible scenarios or conditions by testing 16 different combinations of four techniques designed to tailor content users get from VAs.

• “Ad customization” allows users to choose the ad topics they want or don’t want to receive.
• “Voice deletion” gives users the ability to delete specific voice interactions or all recorded voice data.
• “Voice recognition” provides an option to save the user’s voice for better recognition in the future.
• “Ad Personalization” automatically tailors ads based on prior user behavioral data collected. The study examined the effects of overt ad personalization — when users were informed of, and given a chance to opt out of, automatic tailoring of ads – and covert ad personalization – when such notification of automatic ad tailoring and opt-out option was absent          .

The researchers used a VA application specifically made for this study to eliminate any prior influence or brand loyalty to existing VA systems.

Once installed on their phones, respondents could set preferences according to the four conditions. They were then instructed to ask three health- and lifestyle-related questions, such as, “What is a keto diet?” The VA responded with an answer followed by ad content related to the answer.

After the interaction, respondents answered a questionnaire that measured ad reactance based on measures such as whether they felt angry about the ad content,  perceived the ad as intrusive, or had unfavorable thoughts about the ad content in general. The researchers considered and accounted for other variables, like brand awareness and experience using VAs.

“Everything significant was focused on a combination of customization and personalization techniques,” said lead author Eugene Cho Snyder, an assistant professor at the New Jersey Institute of Technology who earned her doctorate from the Bellisario College at Penn State. “There were no standalone effects. It doesn't work like that.”

The researchers found that combining ad customization and covert ad personalization was most effective in limiting negative ad reactance.

Ad customization by the user increases the sense of control and reduces negative reactions, according to the researchers, but only when the ads are personalized by the VA in a way that’s not apparent to the user. That was a surprise, the researchers said, and suggests that service providers should carefully select the ad and content tailoring features to avoid irking users.

"Having a voice gives a lot of power to users,” Cho Snyder said. “It's a way of opening up a conversation in a natural manner."

The researchers said the insights uncovered in the study can help tech companies better design voice technologies to meet both commercial and user needs.

"Google and Facebook, they all survive on advertising,” Sundar said. “VA technology is not sustainable beyond the initial novelty phase, unless it can bring in ad revenue," he added, noting that the key is to do this by respecting users and giving them control over their experience with the VA.

Jae-Gil Lee, assistant professor at Hallym University, is a co-author of this study. This research was supported by the Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education.