Four Failures of Deliberating Groups

Many groups make their decisions through some process of deliberation, usually with the belief that deliberation will improve judgments and predictions. But deliberating groups often fail, in the sense that they make judgments that are false or that fail to take advantage of the information that their members have. There are four such failures. (1) Sometimes the predeliberation errors of group members are amplified, not merely propagated, as a result of deliberation. (2) Groups may fall victim to cascade effects, as the judgments of initial speakers or actors are followed by their successors, who do not disclose what they know. Nondisclosure, on the part of those successors, may be a product of either informational or reputational cascades. (3) As a result of group polarization, groups often end up in a more extreme position in line with their predeliberation tendencies. Sometimes group polarization leads in desirable directions, but there is no assurance to this effect. (4) In deliberating groups, shared information often dominates or crowds out unshared information, ensuring that groups do not learn what their members know. All four errors can be explained by reference to informational signals, reputational pressure, or both. A disturbing result is that many deliberating groups do not improve on, and sometimes do worse than, the predeliberation judgments of their average or median member

Synthetic Access to L-Guluronic Acid via Fluorine-Directed C-5 Epimerization

L-Guluronic acid is integral to the structures of alginates and to the pathogenesis of Pseudomonas aeruginosa. The exploitation of this hexose in both existing and new contexts is, however, limited by its prohibitively high commercial cost. We report on a short and efficient synthetic route to an L-GulA building block from a simple D-mannose thioglycoside. In this synthesis, the fluorine-directing effect is exploited to achieve a stereoselective C-5 epimerization. DFT calculations illuminate the substituent effects which operate to confer this selectivity