Scientists recently discovered salt can slake thirst and support weight loss. Researchers found evidence of extra-sensory perception (ESP) or a 'sixth sense' a few years ago. These two studies show the potential for science to upend universally accepted ideas, the danger of false positives, and the value of skepticism.
Before the salt study, it was universally accepted that humans drink water after consuming salt to dilute the sodium in their bloodstream. The researchers varied the salt intake of Russian cosmonauts participating in a space simulation over several months. When the subjects consumed more salt, they unexpectedly drank less, as their bodies produced more glucocorticoid hormones that broke down fat and muscle to free up water. However, the cosmonauts felt hungrier as tapping the body's water stores requires energy. The findings suggest eating salt can boost energy usage and therefore weight loss, although the scientists warned that high glucocorticoid levels have been linked to osteoporosis, Type 2 diabetes and various metabolic problems.
Meanwhile, the ESP researchers tested whether people could intuit the future to perform better on tasks. Undergraduates were shown a pair of virtual curtains on a computer screen, and asked to guess which of the curtains concealed a hidden image. Although the image was randomly generated after they guessed, students correctly predicted its location 53% of the time - better than their 50-50 odds. The test subjects also recoiled from scary images before they appeared, more clearly remembered words they would type out later, and had their emotions primed by words they hadn't yet seen.
The lead researcher, Daryl Bem, knew his findings would be subjected to extreme scrutiny. Therefore, he repeated his experiments 10 times, refined his methodology to meet the highest standards, and presented his findings in granular detail. His research sparked a "referendum on evidence itself", according to Slate.
Galvanised by Bem's work, scientists came up with implausible findings then concocted experiments that would generate them without violating any hard rules of research. Three researchers combined several questionable but common research practices - such as altering sample sizes after starting research and settling on hypotheses after collecting data - and found they could raise the risk of false positives from 5% to over 60%. In their most famous study, they invited undergraduates to listen to The Beatles' "When I'm Sixty-Four", then used statistical tricks to suggest the students became several years younger after hearing the song.
Few scientists still accept Bem's findings, especially after he took part in a large-scale replication of ESP tests that ended in failure. The true legacy of his work is that it has raised awareness of how researchers can fiddle with their methods and findings to produce the results they want. Indeed, one scientist who commented on the salt study told the New York Times that the findings need to be replicated.
A scientific paper's subject matter undoubtedly affects the scrutiny it receives. Readers will actively look for mistakes in papers that make outlandish claims such as ESP being real, but may be more accepting of a study that examines salt's impact on the human body, regardless of how revolutionary it is. However, Bem's research and its blowback showed how all research can be manipulated. Scientists should treat supernatural forces and condiments with the same degree of skepticism.