Friday, May 16, 2014

The Scent of a Male

Are the sexes really different or are they merely a social construct?

The question has direct implications for science, and not merely of whether a medication tested on one sex will produce the same result at the same dosage on the other sex.

But, there is also the question of the sex of the researcher. Does the same experiment performed by a male researcher on a rodent yield the same result when performed by a female? And vice versa.

It turns out that the answer is No. When science measures mouse and rat pain responses it sees that afflicted rodents manifest less pain when in the presence of a male researcher than with a female researcher.

Dr. Jeffrey Mogil of McGill University conducted the study. The Economist reports:

Dr Mogil’s team injected the ankles of mice with zymosan A, an inflammatory agent, and monitored what happened when, in some cases, an experimenter stayed in the room, sitting about half a metre away, and when in others, he or she did not. They evaluated evidence of murine pain, caught on videotape, using the “mouse grimace scale”. This measures ear and whisker position, eye-squeezing and the bulging of noses and cheeks to gauge an animal’s level of distress.

Their suspicion that an experimenter’s presence would affect distress levels in some way turned out to be true—but only half the time. Both when the mice were left on their own and when they had any of four female researchers in the room with them, the injections induced visible distress. But when any of four male researchers was there, the animals showed significantly fewer signs of pain. The same was true when the team did the experiment on rats, and also when they used a different pain stimulus, formalin.

Next, the experimenters eliminated the male beings and merely exposed the mice and the rats to male scent. The results were the same. The presence of male scent caused the animals to manifest fewer grimaces.

And yet, if a mouse exposed to male scene was also exposed to female scent, the beneficial effect of the male scent was reduced. More female scent meant more open expression of pain.

But, the researchers asked themselves, were male presence and male scent acting as an analgesic, diminishing the pain, or were the mice inclined, when in the presence of men, to mask their pain?

The results were:

Further experiments, which measured levels of corticosterone, a stress hormone, in the animals’ blood, showed that they were indeed stressed by the mere smell of a man. And examination of gene activity in their pain-producing nerve cells confirmed that these cells temporarily shut up shop at the same time. Simply put, the animals were being scared painless. (A significant increase in faecal pellets suggested they were scared shitless as well.)

Of course, life is not always an either/or proposition. When it comes to pain, the two sexes might complement each other.

At times a physician will need to know where and how it hurts. At another time he will want to find a way to diminish the pain. 

This seems to imply that surrounding yourself with women will enhance your pain sensitivity, while surrounding yourself with males will diminish it.

Surely, these are matters worth contemplating.


Ares Olympus said...

Apparently an excellent demonstration of the difficulty of scientific observation when the state of observation itself changes the results.

It does seem delicate, requiring very subtle testing.

Perhaps with clever enough experiments you could discover similar associations in humans?

Whatever else is true, certainly sensitivity to pain is a subjective thing, and there are clearly advantages to having awareness of pain raised or lower depending on danger or needed performance.

You might think whatever unconscious effects are going on in the mice, or if in humans too, that we could have more conscious control as well. It's a powerful ability to shut down awareness of physical or emotional pain, but also dangerous if you find that's an advantage, so to use wisely we'd need the ability and will to raise and lower awareness of pain based on rational assessment of danger and safety.

Sam L. said...

Did they try male scent with a female present?

The Dark Lord said...

could be a predator response as well ... male predators being more feared ... thus more stress ...