Evans, J. St. B. T. (2008). Dual-processing accounts of reasoning, judgment, and social cognition. Annual Review of Psychology, 59, doi:10.1146/annurev.psych.59.103006.093629.
John Boyd’s OODA Loop is a dual processing model of cognition. The very best discussion of dual processing is Jonathan St. B. T. Evans’ “Dual processing accounts of reasoning, judgment and social cognition” (55-page pdf, Annual Review‘s description) to be published in January 2008, in the Annual Review of Psychology.
The article goes over a tremendous amount of literature in excellent style. Evans synthesizes many sources I’ve mentioned such as Lieberman’s “comparison between thinking and riding a bicycle,” and recent work noting the very strong correlation between working memory and IQ . But he puts everything in a larger context, showing how field after field is adopting dual processing systems, and thus coming ever closer to Boyd’s OODA model.
If you want to know how people think, Evans’ article is the place to start.