When I shower, I know exactly how hot I like my water. It seems to me that I can tell the difference in temperatures within a couple degrees. Have there been any studies done on this?
Have you ever measured the temperature of the water after you’ve determined it to be suitably warm? Do this a few times and keep a record. Human senses are notoriously unreliable at detecting absolute levels or any stimulus, which is why we have light meters, thermometers, sound level meters and scales. I know on hot days, I prefer a cooler shower than I do on cold days, though the comfort level is about the same.
So, not very precise then. I wonder why it seems to be reliable? I also like cooler showers in summer, maybe the body lets you know what temp it “likes” depending on the conditions.
Well, if you aren’t comparing it to a thermometer reading, then what is this “reliability” you perceive? It just boils down to “I can tell what feels right to me at the moment” No great achievement - but precisely what you want when pouring a bath. In short our senses are great for doing what they were meant to do, and standing in for lab equipment isn’t what we were meant to do.
As others have noted, most human senses are notoriously bad at making absolute measurements. This is actually a huge benefit for living things: they can adapt to prevailing conditions and detect/react to relatively tiny (e.g less than one degree) rapid local changes. If we had exquisite sensitivity to absolute conditions, without automatic adaptation, we’d be perpetually digruntled by every variations from 68F (20C) at 65% relative humidity – or whatever your preferences. As it stands, rapid changes, such as walking into shade on a beautiful spring day can make you feel chilly. Imagine if you were constantly wishing the temperature of your surroundings were 1-2 degrees warmer or cooler.
Training can help people refine their senses, but the absolute temperature isn’t one most people will ever be able to refine to high accuracy. Our thermosensors, like Krause’s end bulbs are not linear - e.g. they don’t give a consistent signal at, say 20C, but their signal varies with whether the temperature is rising or falling, how quickly, and other factors. Not only do our sensors have considerable hysteresis (which you can compare to “mechanical wiggle or drift”) but the signal from them doesn’t go to directly to your brain, so you NEVER get the raw data. Each time the signal crosses from one neuron to another, it is effectively processed in some fashion: Integrated or differentiated, over time or area, etc.
Having said that, we are pretty clever, and with experience some people can learn to integrate multisensorial data, unconsciously, to “guess” temperatures accurately in a specific setting: a guy who can feel when the wine is a perfect 68.5 F may not be as accurate at telling of the air conditioning is at 68.5 F.
Interesting, now that I think about it. I probably couldn’t determine a particular temperature of water or an object, but I can tell when one of my kids has even a slight temperature (say, 100.0 or so). Maybe it’s a mom thing.
I can tell when soap or oil is between 85-100 degrees, too, by feeling the pot, but I attribute that to years of soapmaking.