Donald Redelmeier

Who they are

Redelmeier is a physician and clinical researcher who takes questions out of judgment and decision research and asks them inside real hospitals, on real patients, about procedures those patients may have to decide whether to repeat.

The 1996 study, with Daniel Kahneman, followed 154 colonoscopy patients and 133 lithotripsy patients. Lithotripsy is a procedure that breaks up kidney stones using shock waves. Patients reported their pain at intervals during the procedure and gave an overall verdict afterwards. What they said afterwards tracked the worst moment and the last three minutes. Total length barely registered. The lithotripsy half is usually dropped in retellings, and that matters, because it means the result was shown on two procedures rather than one.

The 2003 study, with Joel Katz and Kahneman, was the randomised follow-up on 682 patients. Half of them had a short, less painful interval added to the end of the procedure.

What is his and what is not. The founding paper in this area is Fredrickson and Kahneman (1993), three years earlier, on which Redelmeier is fourth author. Duration neglect, the finding that how long something lasted hardly affects how bad we remember it being, belongs to Fredrickson and Kahneman, not to him. This vault twice credited Redelmeier with it, and correcting that is what created this page. His own contribution is the medical application, which is a real and separate achievement, and it is the reason anybody outside the laboratory ever heard of the effect.

Key papers

Redelmeier, D. A., & Kahneman, D. (1996). "Patients' memories of painful medical treatments", Pain, 66(1), 3 to 8. First author. Observational, 154 colonoscopy patients and 133 lithotripsy patients. Retrospective evaluations tracked the worst moment and the final three minutes. Total duration barely registered.

Redelmeier, D. A., Katz, J., & Kahneman, D. (2003). "Memories of colonoscopy: a randomized trial", Pain, 104(1 to 2), 187 to 194. First author. 682 patients, half randomly assigned a short, less painful interval at the end. The effects were real and small, roughly half a point on ten-point scales, and the number of patients who came back for a repeat procedure over about five years moved only marginally on top of a return rate near half in both groups.

Fredrickson, B. L., & Kahneman, D. (1993). The founding paper. Redelmeier is fourth author. Not his finding.

Key ideas

Both halves of the 2003 trial belong in any honest account. Adding a gentler ending did change what patients remembered. It barely changed what they went on to do. The trial is the strongest evidence in this literature and also the most over-claimed.

The 1996 patients were treated at a time when sedative and memory-blocking drugs were not routine for colonoscopy. The study cannot be re-run in its original form, and that caveat travels with it every time.

Credit runs in a fixed order here. Fredrickson and Kahneman for the effect and for duration neglect. Redelmeier for the medicine. Joel Katz, second author on the trial, is dropped even more often than Redelmeier is.

The reason the medical work matters more than the laboratory version is that it was done on people who had a real reason to remember accurately, and they still did not.

Concepts on this site

Peak-End Rule

Duration Neglect

The Experiencing Self and the Remembering Self

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