The “Yuck Factor”

Abstract A common first reaction to the idea of deliberately infecting research participants in controlled human infection (CHI) research is that it seems intuitively unethical. Scholars have referred to this intuitive response as a “yuck” reaction. Does the fact that CHI research can generate a “yuck” reaction mean that there is some special ethical complexity in this type of research? While some ethicists have argued that CHI research is not ethically distinct except insofar as it might threaten public trust in research, others disagree. This chapter takes on the “yuck” response and whether it serves to signal that CHI research is ethically problematic. The social science and psychology research behind the “yuck” factor helps illuminate why people might react to CHI research in this way, including whether different types of challenge studies can raise more of a “yuck” reaction than others. The chapter concludes by arguing that we should take the “yuck” factor seriously, as it can shape the public reaction to CHI research even though it does not always track ethical issues that are unique to CHI research and sometimes arises out of misfiring intuitions. For certain types of CHI research, it may be important to plan robust public engagement in advance to address the potential for an unfairly negative reception for this research.