It seems to me like demand effects[1] could explain a large fraction of the observed behavior. People like being given money. If you tell them you're conductin

It seems to me like demand effects[1] could explain a large fraction of the observed behavior. People like being given money. If you tell them you're conducting a study to determine if giving them leads to them doing XYZ, it should come as no surprise when they do XYZ, even if the money didn't literally enable it: they are incentivized to XYZ all they can in order to keep the money pump flowing. [1]: https://en.wikipedia.org/wiki/Demand_characteristics https://en.wikipedia.org/wiki/Demand_characteristics