01 April 2013

Fooling Ourselves: Are We Hard-Wired for Optimism?

A while back I read about a couple of studies in medical decision-making by Lucas S. Zier, Douglas B. White, and colleagues. In particular, they looked at how medical surrogates responded to doctors saying that there was very little that they could do for a dying patient.

In 2009 the team reported in the journal Chest:

Sixty-four percent of surrogates expressed a reluctance or unwillingness to believe physicians’ futility predictions. They provided the following four main explanations for this belief: a skepticism about physicians’ ability to achieve complete prognostic certainty, a need to see for themselves that a patient was incapable of recovery, a need to triangulate multiple information sources before believing physicians, and a belief that God could intervene to change the course of an illness. . . .

Surrogates who doubted physician’s futility predictions clustered into the following two general groups: those whose doubt was based on religious beliefs (n = 18); and those whose doubt was based on secular considerations (n = 15), such as past experiences with inaccurate prognostication, a secular belief that future-telling is inherently inaccurate, and a need to triangulate physicians prognostications with other sources before accepting the prognosis as true. Surrogates who doubted physicians’ futility predictions on religious grounds were more likely to request continued life support in the face of a very poor prognosis…, whereas those whose doubt was based on secular concerns were not…
Three years later the researchers published further findings in the Annals of Internal Medicine, also looking at how medical surrogates responded to doctors’ good predictions:
Participants’ interpretations of prognostic statements expressing a low risk for death were relatively accurate, but interpretations of statements conveying a high risk for death were more optimistic than the actual meaning. . . . Interpretations of the statement “90% chance of surviving” did not differ from the actual meaning, but interpretations of “5% chance of surviving” were more optimistic and showed substantial variability.
If I interpret the abstract right, people hearing “90% chance of surviving” generally interpreted that as 90%, with only a slight spread to 95%. People hearing “5% chance of surviving” spread that out into 15%, with the center of the bell curve going as high as 40%.

In interviews, the researchers found two reasons for the distortion of bad news: “surrogates’ need to register optimism in the face of a poor prognosis and surrogates’ belief that patient attributes unknown to the physician would lead to better-than-predicted outcomes.”

In other words, our brains may not process bad medical news rationally or accurately.


Glenn Ingersoll said...

"[O]ur brains may not process [very much at all] rationally or accurately."

J. L. Bell said...

But we seem to do better with good news. The test of the 90% good prognosis suggests our minds can remember percentages in that case. But not at the other end.