Eliezer’s report of Wade’s study is not completely accurate. From the link, emphasis mine:
...some of the B populations [the ones selected for low population] enjoy a higher cannibalism rate while other B populations have a longer mean developmental time or a lower average fecundity relative to the controls.… Thus, the decline in mean population size in the B treatment… is the result of both group selection and individual selection within populations favoring characters responsible for low population size.…
In summary, these results indicate (i) that group selection in the opposite direction to individual selection can produce significant genetic change, (ii) that group selection in the same direction as individual selection can produce results very different from individual selection acting alone, and (iii) that a process of random extinctions with recolonization can establish conditions favorable to the operation of group selection.
Eliezer’s report of Wade’s study is not completely accurate. From the link, emphasis mine: