UNIVERSITY PARK, Pa. -- Simply tweaking the screen size of a smartphone can change how much users trust advertisements, as well as their buying behaviors, according to a team of international researchers.
"While people are using smartphones -- and these days, smartphone screen sizes are becoming bigger and bigger -- they may think that the larger screen sizes are actually enhancing their experience and increasing the amount of information they can take in, but this subtle difference in screen size can also affect them in ways that they may not realize," said S. Shyam Sundar, Distinguished Professor of Communications and co-director of the Media Effects Research Laboratory. "Our study sheds light on how they may be processing information on these new larger screens."
In a study, people who viewed video ads on large screens tended to experience feelings of affective trust, whereas reading text ads on smaller screens created greater cognitive trust, according to the researchers.
"A simple way to put it is that affective trust refers to how you feel about something and cognitive trust refers to what you think about it," said Sundar. "The difference is between what you think and what you feel."
The researchers had expected that cognitive trust would be associated with behavioral trust and buying intention, but they discovered that affective trust was more influential. Participants who viewed video ads on larger screens were more likely to want to purchase a product.
Sundar added that one form of trust is not better than the other, but that they indicate different depths of thinking by mobile users.
"There is a change in the depth of processing," said Sundar. "When users have a large screen, people are processing heuristically, which means they are processing information in a less systematic manner, which may make them more prone to influences from cues in the surroundings and, in general, more open to persuasion."
The feeling of immersion may prompt users who are watching videos on bigger screens to experience a media presentation as if they were inside it.
"If you feel like you're there, you may be more inclined to trust things more," said Sundar. "You feel like you're almost in the environment, so it must be real."
The researchers said this higher sense of immersion tended to change how people processed the information.
"The study showed that those who felt a higher sense of being there in the environment portrayed in the ad were more likely to think about the ad heuristically, rather than systematically," said Sundar. "The same was true for those who felt the ads were more real."
Sundar, who worked with Ki Joon Kim, endowed research professor of interaction science, Sungkyunkwan University, said it only takes small differences in the size of screens to change trust levels and buying intentions. In the study, for example, the researchers tested smartphones with 5.3-inch screens and 3.7-inch screens.
"We are not talking about comparing a 57-inch television screen with a 10-inch screen, we are talking about mobile devices that have relatively small differences in screen size," said Sundar.
The researchers, who released their findings in a recent issue of Human Communication Research, said the study suggests that while one screen size may not be better than the other, consumers may want to reflect on how the screen sizes and types of media are affecting them before they buy a product or sign up for a service.
"If you are using a large screen you may be more likely to trust the vendor and impulsively purchase a product," Sundar said.
Kim said that the study may have implications for the use of virtual reality in mobile advertising. He added that this study may also help guide designers of wearable devices, which could have even smaller screens than smartphones.
"Our findings can provide guidelines for wearable device designers who are challenged to use very small screens to deliver information," said Kim.
The researchers recruited 120 undergraduate students in Korea for the study. One group was assigned an Android smartphone with a 3.7-inch screen and another group accessed the web with an Android smartphone with a 5.3-inch screen.
Participants used the smartphones to visit a website to find a bus schedule. When they accessed the schedule, the website displayed either a video or text-based advertisement before showing the schedule.
After the session, the participants filled out a questionnaire to determine their depth of information processing, level of trust and buying intentions.