In Blink, his focus is on rapid cognition--the thinking that takes place subconsciously and extremely fast (in the "blink" of an eye). Gladwell's research demonstrates that rapid cognition--he also calls it "thin-slicing"--is powerful, sometimes in negative ways. Subconscious racial or gender stereotyping illustrate this notion. Rapid cognition can also be subverted through stress or time pressure, as evidenced by the case of the police officers who suffer a "temporary autism."
On the other hand, rapid cognitions based on deep knowledge and study can be more effective than extremely logical decisions based on a surfeit of information. To illustrate this point, Gladwell draws on the work of marriage therapists who can predict whether a couple will divorce from watching a brief interaction between the two, psychologists who have studied micro facial expressions and can "see" what people are thinking in a way other observers cannot, military tacticians, and emergency room physicians diagnosing heart attacks. In all of these cases, thin slicing based on deep knowledge is a more effective way to make a decision than gathering and analyzing more and more information.
Knowing when to use rapid cognition and when to rely on more measured and logical decision-making is important, as is not allowing our thin-slicing to be disrupted by stress and time pressure. When we understand the gift of instinctive decision making, Gladwell would say, we should be responsible enough to use the gift wisely.
My description of the book does not do it justice--READ IT!!
The key to good decision making is not knowledge. It is understanding. We are swimming in the former. We are desperately lacking in the latter.