The impact of the French double-ballot is controversial. Some have argued that it performs as a plurality system, while others have said that it mimics a proportional representation system. Still another group says it yields its own unique effect. These conclusions have come from theoretical and observational studies. But no one has presented any real experimental evidence on the question. That is our purpose. We wish to carry out laboratory experiments on electoral outcomes, where the voting groups essentially differ only in the number of times they vote — one-ballot vs two. Here we report the results from two such experimental investigations. They suggest that there are double-ballot effects, namely the encouragement of ideological extremism. Further, these pilots serve as foundation for more extensive experimentation.