Abstract: Much of human knowledge comes from experimentation. For instance, do antidepressants affect both mood and thoughts directly, or do they affect thoughts via mood? To test competing hypotheses, one can intervene on a variable (e.g., changing mood using another method) and see how it affects other variables. Good interventions generate information that discriminates between hypotheses, rather than data that confirm hypotheses we already believe. In my dissertation, I modeled adults' and children's intervention selection as a mixture of discrimination and confirmation. Unlike adults who predominantly relied on discrimination, children mostly adopted confirmatory strategies. Merely asking children to explain why they chose certain interventions didn't change the strategies they used. However, older children (9- to 11-year-olds) shifted towards discriminatory strategies after receiving short training that guided them to consider the usefulness of each possible intervention in a given example.

Just as children in my dissertation work gradually learned to grasp the principle of useful extermination, I went through the same process as a scientist. At the end of this exit talk, I wish to very briefly share a "director's cut" of my Ph.D. journey. Below is a perfect summary of this work and the work behind my work:

"It is the usual fate of mankind to get things done in some boggling way first, and find out afterward how they could have been done much more easily and perfectly." — Charles S. Pierces (1882)