Now ants are pretty smart creatures - when working in their colony they perform their tasks extremely efficiently and effectively without being explicitly told what to do. So what causes the circular mill? The secret to the ants success in a colony is also the secret to their downfall. Every thing the ant does depends on what the fellow ant does. They do not think independently.
The role of independent thought in group think is the key point that Suroweicki wishes to make. The ability to think independently is one of the 4 pillars to Suroweicki's theory of the wisdom of crowds (the others being basic subject matter expertise, diversity of opinion and forum for collecting thought). We instinctively believe independent thought to be a fundamental need in personal decision making and rationalising to benefit the first person. Suroweicki's theory is that independent, uninfluenced thought is as important for successful group think. To simplify if person A expresses their opinion to person B, person A's decision making is now influenced and effective decision making is diminished. Individual judgement on occasion can be flawed. Should that flawed decision making influence others then the group judgement can be flawed. Truly independent thought eliminates this problem. In a recent class the question "Is language a virus?" was raised. In this context it can be.
Independent thought is important in the context of the individual (certainly I think pride would encourage us to agree with this) but it could be argued that it is far more important and influential in group decision making.