Brian Sweis
Brian M. Sweis is the first author of the 2018 paper in Science reporting that mice, rats and humans all show a sunk-cost pattern on matched foraging tasks. Once an animal or a person had committed to waiting for a reward, the time already spent waiting predicted whether they saw the wait through, over and above the time still to go. The effect appeared only after the decision to pursue had been taken.
Who they are
A matched foraging task is a design run in near-identical form across species, so that mice, rats and people are doing the same thing rather than something loosely analogous. That is what makes the comparison interesting, and it is also where the objection to it lands.
Nothing beyond his authorship on this paper is established here.
Key papers
Sweis, B. M., Abram, S. V., Schmidt, B. J., Seeland, K. D., MacDonald, A. W., Thomas, M. J., & Redish, A. D. (2018). "Sensitivity to 'sunk costs' in mice, rats, and humans", Science, 361, 178 to 181. First author. The senior author is A. David Redish, who has no page on this site yet.
Key ideas
Why the result matters for the argument. If a sunk-cost pattern appears in mice, it is hard to explain the human version purely as a learned moral rule about not being wasteful. That makes his paper the main problem for the account carried at Waste Aversion.
Contested, and this site records it as contested. A 2021 paper in Science Advances argues that the task cannot separate a sunk-cost effect from ordinary variation in how a reward is valued, and that an agent simply maximising reward reproduces the same pattern without any sunk-cost reasoning at all.
Report the finding and the objection together, never one without the other. Both are set out in full at The Concorde Fallacy, and this site treats the disagreement as live rather than settled.
Concepts on this site
The Concorde Fallacy, the animal-behaviour question his result speaks to
Waste Aversion, the learned-norm account his animals are a problem for
Sources
- Sweis, B. M., and colleagues (2018). Science, 361, 178 to 181. Abstract only.
- "Apparent sunk cost effect in rational agents", Science Advances (2021).* The objection, held alongside the finding.
- Vault record, 2026-09-11, for Why You Finish the Series You Stopped Enjoying.