In Wharton marketing professor George Day’s world, the term “peripheral vision” means the ability of companies to detect, interpret and act on distant signals, whether a rumor heard about a new rival, a newspaper article about a new medical device, or the popularity of a blog started by a dissatisfied customer. Day and co-author Paul Schoemaker have written a book entitled, appropriately enough, Peripheral Vision: Detecting the Weak Signals That Will Make or Break Your Company, designed to help firms avoid being blindsided by unexpected events. According to the authors, only 20% of companies have succeeded in developing peripheral vision well enough to stay ahead of their competitors.…