Cognitive psychologist researches user perceptions of smartphones.

Size matters. That’s true in smartphones as well as other things, at least according to a cognitive psychologist who’s looked at the impact of handset screen size on user experience.

Thomas Thornton, a senior research scientist at Perceptive Sciences in Austin, Texas, has concluded from a study of how users respond to handset screen size that the trend toward smaller devices butts heads with the need for smartphone functionality.

Smartphone design could affect the growth of the market for these devices, which have started to become more ubiquitous. Gartner estimates smartphone sales grew 50% last year, to 72.9 million units, and forecasts there will be 450 million smartphones shipped globally by 2010.

Another study, by Berg Insight, predicts 113 million smartphones will be sold this year, reaching 365 million in 2012. Smartphones will account for 22% of all handsets sold globally in 2012, more than twice their current market share.

Thornton and his team of usability experts evaluated four smartphones for ease of navigation, look and feel, usability and ergonomics. The handsets were the Research in Motion BlackBerry 8800, Palm Treo, Nokia E62 and Motorola Q. Palm and Nokia are among Perceptive Sciences’ clients.

PERCEPTION MATTERS
Screen size matters, he says, because as the screen size increases, so does the space to display content. Thornton developed a metric showing the ratio of the screen size to the device size to rate smartphones on how users will perceive the interface. (See graphic.) The Apple iPhone came out on top because its 3.5-inch (diagonal) takes up most of the handset’s hardware.

Thornton says work with a variety of focus groups on smartphones shows users want a relatively large screen, and also want a touchscreen. One of the advantages of a touchscreen like the iPhone is that users who want large buttons, albeit virtual ones, can change the size when they are displayed on a touchscreen.

Screen Size vs. Device Size

Screen size especially affects the browsing experience on smartphones. Thornton says that’s where the iPhone in particular stands out, although he says the user experience is better over a Wi-Fi connection than the relatively slow AT&T EDGE network. The Safari browser on the iPhone is “spectacular,” he says, although he criticizes the iPhone’s inability to create and edit documents.

The researcher also said the browser on Nokia’s E62 was the favorite among the focus groups, although some teenagers were disappointed with its access to the MySpace site, while others complained that hard keys had to be used to navigate.

Will keypads go away on smartphones? Thornton is among those who think they will, because they take up valuable space on the handset. Keys can be used in software, like the iPhone or the HTC Touch, he says, which has the advantage of making them programmable. The Touch, which hasn’t started selling in the United States yet, is a Windows Mobile 6 handset.

Thornton thinks smartphones will adopt a cable TV approach in the future by seeking market segments rather than trying to be all things to all people. There will be smartphones built primarily for gaming, others for Internet browsing and so on. It is difficult for one phone to do everything just because of the processing limits.

Of the four handsets Thornton’s team evaluated, the best-rated from a usability standpoint was the Palm Treo 700wx, which runs Windows Mobile 5 on the Verizon Wireless and Sprint networks. The Treo has a touchscreen, although not as large as the iPhone, and is easy to customize and navigate, he says. Other benefits include its ability to create and edit documents.

The Nokia E62 was second in the research, followed by the BlackBerry 8800 and the Motorola Q. The iPhone and HTC Touch weren’t rated because they are too new to have been researched with user panels. Thornton says the Q was downgraded because its keys could be used in multiple ways, which was confusing to users.

Another user preference brought up in the research, he says, is that consumers are reluctant to change interfaces or use a new technology once they have learned and become accustomed to one. That’s the advantage that Windows has. Thornton says this user reluctance to change should discourage handset manufacturers from making large-scale modifications in the user interfaces of their devices.

Thornton also cautions device manufacturers and developers that consumers look at smartphones as “unified whole, not collections of parts.” Any application or service should be developed as part of the entire user interface.

“By not understanding how each of these components add value and how they interact to create the overall ‘gestalt’ that is the device,” Thornton says, “developers and marketers can easily be missing the forest for the trees in their race to outpace competitors.”