We tested 44 variations in profiles of climate change activists to see what affected willingness to associate with them. The largest effects were from activists' perspectives on climate change, how often they pressure others, gun control views, and party affiliation. If implemented as a traditional factorial experiment, this experiment would require 648,000 conditions and an infeasibly large sample. We obtained our results much more efficiently via an experimental design rare in communication research. Conjoint experiments will be useful to science communication researchers who wish to simultaneously test many factors of complex stimuli, such as individuals, organizations, technologies, or policies.