The design of the humble cash machine isn't something most of us have given much though to – but it's a perfect example of how enhancing UX can make a difference to something a lot of people use on a regular basis, improving both their customer experience and their opinion of the brand that's delivering it.

This was the task given by US arm of Citibank to Critical Mass – the global digital agency, not the direct action-led cycling group. Critical Mass has designed the front end of Citibank's online banking – as part of working across on the bank's branding including its mortgage service and rewards programme. Next its sights were set on the bank's ATMs (as I'm sure you're aware Americans call cash machines).

"Citi was one of the original pioneers of ATMs back in 1977," says Aaron Rosenberg, Critical Mass's VP for program management and delivery. "Their ATMs hadn’t been updated in 15 years or so – and [like most bank ATMs] were some of their least appealing experiences. When you visit the ATM, it seems so ordinary and everyday. We asked ourselves why is that?"

"We asked what could be done to make it smarter, easier, faster and above all really more human. That was our challenge. That informed the initiative and the subsequent design implementation."

Use the slideshow controls above and right to read the rest of this story, and to see the evolution of the design of Citibank's ATMs.