When rare, assessment rules which positively judge a refusal to help bad people produce a poor correlation between reputation and behavior. It is this correlation that generates the assortment crucial in sustaining

cooperation through indirect reciprocity. Only assessment rules that require good deeds to achieve a good reputation guarantee a strong correlation between behavior and reputation. (C) 2011 Elsevier Ltd. All rights reserved.”
“Background: Many patients with Parkinson’s disease (PD) develop freezing of gait (FOG), which may manifest as a hesitation or “”getting stuck”" when they attempt to pass through a doorway. In ISRIB chemical structure two experiments, we asked whether FoG is associated with (1) a deficit in internal representation of one’s body size with respect to a doorway and (2) a mismatch between imagined and actual walking times when passing through a doorway.

Methods: Apoptosis inhibitor 23 subjects with PD (11 with and 13 without FoG) and 10 control subjects of similar age completed

two experiments. In the Passability experiment, subjects judged the passability of doorways with different apertures scaled to their body widths. We compared passability estimates across groups. In the Imagery experiment, subjects timed themselves while: (1) imagining walking through doorways of different apertures and from different distances and (2) actually walking in the same conditions they had just imagined. We compared imagined and actual walking durations across groups and conditions.

Results: In the Passability experiment, the estimated just-passable doorway was wider, relative to body width, in PD subjects than in control subjects, but there was no difference between PD subjects with and without FoG. In the Imagery experiment, subjects in all groups walked more slowly through narrow doorways than though wide doorways, and subjects with FoG walked much more slowly through Akt inhibitor the narrowest

doorways. PD subjects with FoG showed a large discrepancy between actual and imagined time to pass through narrow doorways, unlike PD subjects without FoG and control subjects.

Conclusions: The equivalent passability judgments in PD subjects with and without FoG indicate that FoG is not specifically associated with a deficit in ability to internally represent space with reference to body size. However, the large difference in duration between actual and imagined walking through narrow doorways in subjects with FoG suggests that PD subjects with FoG did not know how much they would slow down to pass through narrow doorways. The observed discrepancy between imagined and actual walking times may point to a specific problem that contributes to the occurrence of FoG.