Please check out this 1-click (5 sec) user test. http://www.solidifyapp.com/p/113 All results will be published on Digital Point.
Thank you for participating. This little test shows that the best direction for sorting multi-column list items is vertical. 90% of respondents clicked on the vertical second item in this 2 column list, 10% clicked on the horizontal second item. This result is in line with the telephone book argument and common sense approach of human eye movement (top to bottom). Twitter @michelkusters Both me and this test are not affiliated with Derren Brown.