The phrase comes from a paper from Timothy Wilson and colleagues, describing a variety of studies in which participants were asked to sit and think in a bare room for 15 minutes. In one of the studies, the room contained a device they could use to shock themselves, and almost half did—even though they previously answered that they’d pay to avoid a shock!
Related:
Q. Vivid experiment demonstrating that people prefer doing to thinking?
A. Wilson et al asked people to sit and think for 15 minutes but offered them a device they could use to shock themselves, and many did, despite previously stating that they’d pay money to avoid a shock!
Wilson, T. D., Reinhard, D. A., Westgate, E. C., Gilbert, D. T., Ellerbeck, N., Hahn, C., Brown, C. L., & Shaked, A. (2014). Just think: The challenges of the disengaged mind. Science (New York, N.Y.), 345(6192), 75–77. https://doi.org/10.1126/science.1250830