I really enjoyed the 2006 Science paper by Dijksterhuis, Bos, Nordgren and van Baaren on deliberation without attention. Then came Acker (2008) with a meta-review and the suggestion that there is “little evidence” of an advantage of deliberation without attention.
Today, from the latest issue of Judgment and Decision Making: Are complex decisions better left to the unconscious? Further failed replications of the deliberation-without-attention effect by Dustin P. Calvillo and Alan Penaloza.
The summary seems to be that deciding without deliberation, immediately after the stimulus is presented, might sometimes be better than deliberation. But not with distraction post stimulus.
The moderators of the effect—there seems to be something going on in a few studies!—are still not well understood.