The book "Emotional Design" (http://www.amazon.com/o/asin/0465051367 http://www.amazon.com/o/asin/0465051367 ) has lots of studies about how people complete tas

The book "Emotional Design" (http://www.amazon.com/o/asin/0465051367 http://www.amazon.com/o/asin/0465051367 ) has lots of studies about how people complete tasks better and have better experiences with functionally equivalent products that are well designed. The beginning has a well-cited example of how customers could use Japanese ATMs better when they were made "pretty". Suspecting it was an artifact of the Japanese cultural love of beauty and craftsmanship, they tried it in Israel, which was more culturally hard-nosed and pragmatic. The improvement in usability was even more pronounced.