There’s an interesting article on Psyblog offering evidence that powerful claims for unconscious thought in complex decision-making are overblown.
A team at the University of New South Wales and the University of Essex, writing in the Quarterly Journal of Experimental Psychology, describe four separate experiments searching for the fabled power of unconscious thought (Newell et al., 2009). One of these was a straight replication of Dijksterhuis’ study and the other three were variations on the theme. All four experiments pointed towards the same conclusion:
"In stark contrast to the claims in the literature and the media we found very little evidence of the superiority of unconscious thought for complex decisions." (Newell et al., 2009; p.19).
Indeed in more naturalistic conditions conscious thought was sometimes superior to unconscious thought.
Two other recent papers published in the journal Judgement and Decision Making also failed to find the purported benefit for unconscious thought. Acker (2008) analysed the results of 17 attempted replications of the unconscious thought effect. These studies showed that it was conscious thought that was most effective in complex decision-making and indeed unconscious thought tended to muddy the waters.
I haven’t read "Blink," which is the book whose evidence is being challenged here, so I can’t say whether its premise is overstated, but there does seem to be a trend of over-simplification of complex issues to fit a neat thesis, as evidenced by criticism of books such as The Long Tail and Free.
But in general, I find in my own practice that the power of mindfulness is that it allows us to check out the validity of hunches, intuitions, and gut feelings, which aren’t necessarily to be relied on.