It is well known that Expedia Inc., the online travel titan, does thousands of tests on users of its websites to find out what does, and doesn't, work. In so-called "A/B testing," the company presents users with different versions of a website. Then it compares how users respond.
What's less known is how Expedia has tapped into the science of electromyography for its work.
A case in point is the Scratchpad app on the Expedia.com branded points of sale worldwide.
Scratchpad is a kind of digital scrapbook for saving searches. But unlike other ways of tracking prices, it always updates the pricing. So a user only sees fares and rates that are actually bookable, not expired.
The tool works across platforms, meaning a user can start researching a trip on their mobile and tablet device and then go to a desktop or laptop of Expedia.com and see their previous work saved in the Scratchpad app there.
Scratchpad was cooked up thanks to old-fashioned market research. In the past five years, the average number of airline ticket searches an Expedia user makes before buying a flight has spiked from 15 to 48.
Noting that most users write notes to track the details, Expedia invented Scratchpad as a replacement for note-taking. But getting users to find and use the unfamiliar tool through A/B testing had proven limited.
Expedia found that Scratchpad doubled what it called "the compulsion rate," the percentage of users who returned from day to day. Visitors who register for Scratchpad and use it are much more likely to return to the site within a day than those who don’t.
But few consumers were ever finding Scratchpad in the first place.
Executives wanted to shepard users to Scratchpad. So they studied users' attention while visiting their site using unusual ways of tracking attention.
Tracking the "compulsion rate"
Attention isn't the kind of thing you can study easily. That's why armies of user experience and user interaction experts have sprung up, to help digital companies like Expedia take advantage of the latest psychological research on how to hook the attention of online shoppers.
Case in point: Expedia’s chief product officer John Kim, and senior product manager, notifications, Pooja Vithlani, tapped Nir Eyal, a user-experience consultant, to use some bio-feedback methods to tests Scratchpad's addictiveness for users.
Late in spring 2014, consultants and executives gathered at Expedia's mothership in Seattle. Behind one-way view mirrors, they watched tests of consumers interacting with Scratchpad, breaking down the shopping process into its atomic parts.
The tests have been reported in a long-form story in MIT Technology Review
Experts taped a pair of electrodes to a users' brow, above their left eye, to measure frowning. Another pair was fixed to the user's left cheek, to measure smiling. As the customer shops, a visual readout of the electrodes’ measurements was displayed. According to MIT Technology Review:

"When one user looked at photos of the Westin Maui, the smile sensors spiked: a jolt of joy—and potential paydirt for Expedia."
But like many customers in the test, this one couldn't find the Scratchpad button on Expedia.com without prompting.
Over time and testing, the Expedia team came up with new ideas. They've applied these to their site. They say the results have tripled the compulsion rate and doubled the repeat-visit rate -- significant leaps from a year ago.
For details, you'll need to read the full story Compulsive behavior sells, in MIT Technology Review.
It was the use of electromyography that caught our attention, so to speak.
This was not Expedia's only experiment with bio-feedback studies. In November 2014, it had consumers shop online for hotels that they might like to stay in while their eye gaze and facial expressions were tracked using electromyography.
If it seemed like they were happy or irritated according to the readout, the consumer was asked about their reaction to the hotel photo. This data was used to determine what kind of images work best for marketing. (Photo above is of a subject participating in this Expedia Inc experiment.)
MIT Technology Review: How Expedia made Scratchpad more addictive
See Tnooz's related coverage of Scratchpad
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How Expedia ads now trail you from desktop to mobile