This paper tracks economists’ rising, yet elusive and unstable interest in
collective decision mechanism after World War II. We replace their
examination of voting procedures and social welfare functions in the 1940s
and 1950s in the context of their growing involvement with policy-making.
Confronted with natural scientists’ and McCathythes’ accusations of
ideological bias, positive studies emphasizing that collective decisions
mechanisms were unstable and inefficient, and normative impossibilities,
economists largely relied on the idea the policy ends they worked with
reflected a “social consensus.” As the latter crumbled in the 1960s,
growing disagreement erupted on how to identify and aggregate those
individual values which economists believed should guide applied work, in
particular in cost-benefit analysis. The 1970s and 1980s brought new
approaches to collective decision: Arrow’s impossibility was solved by
expanding the informational basis, it was showed that true preferences
could be revealed by making decision costly, and experimentalists and
market designers enabled these mechanisms to be tested in the lab before
being sold to those public bodies looking for decision procedures that
emulated markets. In this new regime, the focus paradoxically shifted to
coordination, revelation and efficiency, and those economists studying
collective decision processes were marginalized.