Today in science: Men insensitive to increases in vibration
Amusing preliminary data from a tactile perception experiment in my lab seem to reveal that women are much more sensitive than men to increases in the intensity of small vibrations.
The experiment was designed to probe the brain's processing of tactile stimulation using two small vibrating pads. Participants in the experiment placed their thumb and middle finger against the apparatus as the vibrations varied from low to high intensity, and the experimenters measured their sensitivity. A bit like a hearing test, subjects responded when they felt stimulation to their thumbs. The “masking” stimulus, on the middle finger, was meant to degrade their performance. Measuring exactly how much the masking stimulus affects the sensitivity of the thumb will tell us more about how these stimuli are processed in the somatosensory cortex, the chunk of the brain that creates our sense of touch.
I generally have an automatic cringe-reflex to any and all mention of gender differences in psychology or neuroscience papers, for reasons we can discuss later, but a first pass over the data from this experiment shows some pretty un-subtle effects:
In the top panel, the data from the male participants (n=4); below, the women (n=4). The x-axis of each graph represents the intensity of the thumb stimulation, increasing from left to right. The y-axis indexes the percentage of trials on which participants correctly detected the target stimulus. Data from women is well described by typical psychometric functions: pretty bad at low intensity, increasing through the middle range until it reaches 100% (ceiling) accuracy. But look at the men's data—they do alright (better than the women, in fact) at low levels, but show basically no improvement with added intensity, no matter how much.
This data is absolutely begging for a sexy headline. If you can think of a joke about men, women, and vibrators, it's probably been made by some member of my lab this afternoon. Equally hilarious, some of the attempted justifications by the male half of the dataset: “It's our hands, they're so callused from physical labor!” “We were clearly just squeezing the apparatus so hard with our manly strength!” “But our performance is great at low intensity! It's great across the board!” etc.
In all seriousness, this is preliminary data and we don't yet know much about what it actually means. The experiment will have to be repeated with better controls—for example, to address the reasonable concern that sensitivity might be affected by how tightly you're squeezing the apparatus—and more participants. But as a fan of any dataset that brings the lab together for a few minutes of combined speculation and pith, I'm already liking this project.
