Updating my iPhone 4 to iOS7 was pretty much a fiasco.

Not only did the process halt about 3/4 of the way through, but I was then forced to wipe my phone, start clean and  reload my latest backup. All told, this gobbled over an hour of my day, leaving me with a sour stomach, elevated blood pressure, and an aura of co-mingled sweat and fear. My reward for relying so much on technology. Thanks, Apple. I can’t wait to update the iPad.

The real surprise came when my iPhone returned to life. I mentally kick boxed myself for having reflexively clicked “yes” on the update request before first reading up on what to expect. As you probably know by now, while the past few “minor” iOS updates had essentially left the interface intact, this new operating system was…different. Brighter colors, less texture and shading, new icons, and new security. Like an alternate sci-fi universe that’s close but not quite like our own, simultaneously jarring and comforting.

I was forced to halt to my day a second time to pay serious attention to this unexpected challenge. A flood of questions: What was new? What was removed? What features switched places? Would I like this new interface over time? Was it better than the old iOS?

The Struggle of New vs. Old Users

Faced with the redesign, I immediately thought of what marketers know as the Primacy Effect. No, it’s not a hotly anticipated Tom Cruise movie. It’s the psychological tendency to remember and favor what we know over what comes later. The primacy effect is our bias towards the familiar. It dramatically impacts our initial experience with any new redesign, whether it’s a Web site, a car interior or a mobile phone, and it often reveals itself as an initial lag in adoption or acceptance. Smart companies and marketers recognize this phenomenon.

Which Test Won recently presented an excellent example of this effect (now in their archives). In an A/B test, marketers compared click thrus on two newsletter formats: the original text-only version (the control) and a new, slicker HTML version (the redesign). They segmented the audience by subscription date (newer vs. older subscribers) and ran an email test to see whether the new format increased the number of clicks on linked offers in the email.

The test data showed that newer subscribers significantly and more frequently clicked on links in the new HTML format. Success! However…long-time or repeat list members  clicked less frequently on the HTML version and at about the same rate as they’d previously done on the text-only version. Follow-up testing suggested that this was merely the primacy effect in action, not a dislike of the new format. The HTML version became the standard, and long-time members eventually adjusted.

What can we learn from this experiment?

• First, understand your audience. The segmentation of repeat vs. new subscribers was a savvy approach to analyzing the short- and long-term effects a redesign. There’s no other way do detect the primacy effect.
• Second, test over a longer period of time. The Which Test Won case study shows how the primacy effect can give the control version a short-term advantage over the new variant. Don’t be in such a hurry to conclude your testing.
• And third, consider incremental change over radical redesign. If the lion’s share of your business depends on repeat customers, ease them into change through communication and experimentation.

Back to my iPhone

After learning enough of iOS7 to regain control of my phone, I launched an informal survey of my iPhone-loving acquaintances. It revealed that while few of us love the new iOS7, we’re all resigned to accepting it. Apple’s most certainly got a handle on this, having tested and retested the interface, curried the favor of influential analysts and reviewers, and adjusted iOS7 enough to limit any customer backlash. They know that the abundance of cool, Android-like features will be a hit with new customers and that the majority of us existing customers will fall in line, as we always do.

If you feel that learning this new iOS is a waste of your time, go ahead and blame Apple. But in the end, as we grit our teeth and rewire our existing phone habits, recognize that we have the primacy effect to thank as well.