Here's an interesting fact about sexual dimorphism: On average, if you were born a male, your hands are a little bit different from those of someone who was born a female. Most men have a pointer finger that is a little bit shorter than their ring finger. Most women have a pointer finger that's about the same length as their ring finger, if not a little longer.
People have noted this differences between the sexes for centuries. But what's it mean? Truth is, we really aren't sure yet. But it is correlated to a lot of awfully interesting things. In fact, some scientists think "the finger thing" (as I like to call it) is a hallmark of prenatal hormone exposure. Because of that, in the scientific literature, you'll find lots of examples of studies that try to find a connection between the finger thing and seemingly disparate traits, such as sexual orientation and gender expression.
We talked about the finger thing on a recent episode of the Sex is Fun podcast—what it's all about, what fingers could be telling us about people, and why it's maybe all just a bunch of hooey. Take a listen!
Also, for the record: My right hand has lady fingers. My left hand does not. How about you?
Science is the best method we have for understanding the world. That doesn't mean that everything scientists ever think they've figured out is correct. And it doesn't mean that we're doing science in the best way possible right now.
For a great illustration of this, I recommend reading Jonah Lehrer's new piece in WIRED, about the problems we run into as we learn more about individual parts of complex systems and then assume that we understand the big picture of how those parts work together. A lot of scientific research, particularly in medicine, operates off assumptions like this and it can lead to big mistakes. Case in point: Back pain. In this excerpt, Lehrer explains how MRI technology that allowed doctors to get a better look at the spines of people with back pain led them to make inaccurate conclusions about what was causing the back pain.
The lower back is an exquisitely complicated area of the body, full of small bones, ligaments, spinal discs, and minor muscles. Then there’s the spinal cord itself, a thick cable of nerves that can be easily disturbed. There are so many moving parts in the back that doctors had difficulty figuring out what, exactly, was causing a person’s pain. As a result, patients were typically sent home with a prescription for bed rest.
This treatment plan, though simple, was still extremely effective. Even when nothing was done to the lower back, about 90 percent of people with back pain got better within six weeks. The body healed itself, the inflammation subsided, the nerve relaxed.
Over the next few decades, this hands-off approach to back pain remained the standard medical treatment. That all changed, however, with the introduction of magnetic resonance imaging in the late 1970s. These diagnostic machines use powerful magnets to generate stunningly detailed images of the body’s interior. Within a few years, the MRI machine became a crucial diagnostic tool.
The view afforded by MRI led to a new causal story: Back pain was the result of abnormalities in the spinal discs, those supple buffers between the vertebrae. The MRIs certainly supplied bleak evidence: Back pain was strongly correlated with seriously degenerated discs, which were in turn thought to cause inflammation of the local nerves. Consequently, doctors began administering epidurals to quiet the pain, and if it persisted they would surgically remove the damaged disc tissue.
But the vivid images were misleading. It turns out that disc abnormalities are typically not the cause of chronic back pain. The presence of such abnormalities is just as likely to be correlated with the absence of back problems, as a 1994 study published in The New England Journal of Medicine showed. The researchers imaged the spinal regions of 98 people with no back pain. The results were shocking: Two-thirds of normal patients exhibited “serious problems” like bulging or protruding tissue. In 38 percent of these patients, the MRI revealed multiple damaged discs. Nevertheless, none of these people were in pain. The study concluded that, in most cases, “the discovery of a bulge or protrusion on an MRI scan in a patient with low back pain may frequently be coincidental.”
This is a complicated problem without a clear solution right now. But we definitely need to have discussions like this so that we can work toward making science and medicine better.
Via Espen in Submitterator