Statistical validation of results, as Shaffer described it, simply involves testing the null hypothesis: that the pattern you detect in your data occurs at random. If you can reject the null hypothesis—and science and medicine have settled on rejecting it when there's only a five percent or less chance that it occurred at random—then you accept that your actual finding is significant.
The problem now is that we're rapidly expanding our ability to do tests. Various speakers pointed to data sources as diverse as gene expression chips and the Sloan Digital Sky Survey, which provide tens of thousands of individual data points to analyze. At the same time, the growth of computing power has meant that we can ask many questions of these large data sets at once, and each one of these tests increases the prospects than an error will occur in a study; as Shaffer put it, "every decision increases your error prospects." She pointed out that dividing data into subgroups, which can often identify susceptible subpopulations, is also a decision, and increases the chances of a spurious error. Smaller populations are also more prone to random associations.
In the end, Young noted, by the time you reach 61 tests, there's a 95 percent chance that you'll get a significant result at random. And, let's face it—researchers want to see a significant result, so there's a strong, unintentional bias towards trying different tests until something pops out.
Young went on to describe a study, published in JAMA, that was a multiple testing train wreck: exposures to 275 chemicals were considered, 32 health outcomes were tracked, and 10 demographic variables were used as controls. That was about 8,800 different tests, and as many as 9 million ways of looking at the data once the demographics were considered.
You may have more in common with Kanzi, Panbanisha and Nyota, three language-competent bonobos living at Great Ape Trust, than you thought. And those similarities, right at your fingertip, might one day tell scientists more about the effect of culture on neurological disorders that limit human expression. Among humans, pointing is a universal language, an alternative to spoken words to convey a message. Before they speak, infants point, a gesture scientists agree is closely associated with word learning. But when an ape points, scientists break rank on the question of whether pointing is a uniquely human behavior. Some of the world's leading voices in modern primatology have argued that although apes may gesture in a way that resembles human pointing, the genetic and cognitive differences between apes and humans are so great that the apes' signals have no specific intent. Not so, say Great Ape Trust scientists, who argued in a recently published scientific paper, "Why Apes Point: Pointing Gestures in Spontaneous Conversation of Language-Competent Pan/Homo Bonobos," that not only do Kanzi, Panbanisha and Nyota point with their index fingers in conversation as a human being might, these bonobos do so with specific intent and objectives in mind.
Cached
