Daubert and Marshmallows

By Michael Caruso

As federal—and now Florida state—practitioners know, courts use the Daubert standard to assess whether an expert witness's scientific testimony is based on valid reasoning that a jury can properly apply to the facts at issue. Under Daubert, courts are to consider the "validity" or "reliability" of the evidence in question, its degree of "fit" with the facts and issues in the case, and the risks or dangers that the evidence will confuse the issues or mislead the jury.

 

In assessing reliability, the prevalence and significance of peer review can affect a court's decision when determining whether the scientific community has generally accepted an opinion. The weight given to peer-reviewed opinions, however, is not a bright-line rule. Depending upon the evidentiary standard and the offered expert opinion, the importance of peer review varies when assessing admissibility. Over the years, many "settled" scientific theories have been discredited by belated peer review —fiber analysis, hair analysis, ballistics, bite marks, and tool marks. 

 

Last week, another settled theory—"The Marshmallow Test"—took a hit. The marshmallow test is an experimental design that measures a child's ability to delay gratification. For this test, the researcher gives a child the option of waiting a bit to get their favorite treat or, if not waiting for it, receiving a less-desired treat. The minutes or seconds a child waits measures their ability to delay gratification. According to the study, the kids who couldn't hold out long generally grew through their teens, 20s, and 30s quicker to frustrate, weaker in academic and social skills, and with more drug use, mental health, and weight issues.

 

But the latest follow-up study casts doubt that a preschooler's response to a marshmallow test can predict anything at all about her future. Following the subject children into their 40s, the new study finds that kids who quickly gave in to the marshmallow temptation are generally no more or less financially secure, educated, or physically healthy than their more patient peers. The amount of time the child waited to eat the treat failed to forecast roughly a dozen adult outcomes the researchers tested, including net worth, social standing, high interest-rate debt, diet and exercise habits, smoking, procrastination tendencies, and preventative dental care, according to the study published in the Journal of Economic Behavior and Organization.

As Daubert acknowledges, peer review has its limitations: "in some instances well-grounbded ut innovative theories will not have been published . . . Some propositions, moreover are too particular, too new, or of too limited interest to be published." But, as we see here with marshmallows (and with fiber analysis, hair analysis, ballistics, bite marks, and tool marks), continued research and testing may be enlightening.