Dilip Soman
Dilip Soman is a behavioural scientist whose 2001 work asked whether sunk costs of time behave like sunk costs of money. A sunk cost is something you have already spent and cannot get back, and the fallacy is carrying on with something purely because of what it has already cost you. His question is the one underneath every sentence that begins "I have already watched ten hours of this", and his answer is why this publication will not borrow the confidence of the money research when it writes about hours.
Who they are
Soman works on consumer psychology, on mental accounting, which is the habit of filing money into separate mental pots rather than treating it as one pool, and on how people handle time. With John Gourville he also worked on payment depreciation, the idea that the sting of a payment fades as time passes, which is the finding usually sitting behind the story about the gym membership nobody uses. That work is held here second-hand and needs checking before it is used.
Key papers
Soman (2001). On whether sunk costs of time behave like sunk costs of money. Held at listing and abstract level only. A registered-report replication exists in the International Review of Social Psychology, doi 10.5334/irsp.883. A registered report is one the journal accepts on the strength of its method before any results exist, which removes the incentive to go looking for a finding afterwards.
Gourville, J. T., & Soman (1998). On payment depreciation. Held second-hand only, and flagged in the vault as needing checking before use.
Key ideas
Two sides, then the line. On one side, the sunk-cost effect for money is one of the steadier findings in decision research and turns up repeatedly. On the other, when the cost is time rather than money the effect is markedly more volatile, with several outright failures to find it. We land with the second, because a television series is a time case and it does not inherit the money literature's track record.
A plausible reason for the asymmetry is that money is countable and time is not. You can say exactly what a ticket cost. You cannot easily say what ten hours cost you, because there is no receipt and no account to balance.
The practical consequence is uncomfortable. "I have already put ten hours into this" feels like the same argument as "I have already paid for the ticket". The evidence says it is a weaker one.
Concepts on this site
Sources
- Soman (2001). On time versus money sunk costs. Listing and abstract level only.
- Registered-report replication, International Review of Social Psychology, doi 10.5334/irsp.883.
- Gourville, J. T., & Soman (1998). On payment depreciation. Second-hand, unchecked.