Human temperature perception

Schilcote

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I'm writing a video game in which the character's body temperature is a mechanic.

At what point do people feel cold/hot?

My understanding is that it has more to do with changes in temperature than absolute temperature- a person who moves into a room that's 5 degrees (Celsius) colder than the one he was just in will feel very chilly, but if you slowly lower the temperature of a room by 8 degrees its occupant might not even notice.

Of course, exact numbers are impossible with living things, since there's so many variables, but I just need ballpark averages. Anyone have any useful data?
 

mirandashell

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There are loads of variables, besides ambient temperature.

For instance, is the character wearing a lot of clothes? Do they have a fever? Do they have good blood circulation?
 

Schilcote

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There are loads of variables, besides ambient temperature.

For instance, is the character wearing a lot of clothes? Do they have a fever? Do they have good blood circulation?

I don't know. :p

Well, that's an exaggeration. It's a safe assumption that the character is healthy.

He'll be able to put different clothes on to alter his transfer coefficient, though.

I'm thinking that it'd just be a function of Δt, wouldn't it?
 
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Schilcote

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The Greek character Δ represents change, a formal definition might be "Δn=n as it was some amount of time ago - n as it is now".

Maybe math-talk isn't a good idea on a forum about English and liberal arts :p (it's the sevens you have to look out for, you know).
 

benbradley

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I'm writing a video game in which the character's body temperature is a mechanic.
A mechanic??? Do you mean a parameter?
At what point do people feel cold/hot?

My understanding is that it has more to do with changes in temperature than absolute temperature- a person who moves into a room that's 5 degrees (Celsius) colder than the one he was just in will feel very chilly, but if you slowly lower the temperature of a room by 8 degrees its occupant might not even notice.

Of course, exact numbers are impossible with living things, since there's so many variables, but I just need ballpark averages. Anyone have any useful data?
Perhaps also important are humidity and if there's any air movement (from a fan or central HVAC).

This might need some experimentation.
The Greek character Δ represents change, a formal definition might be "Δn=n as it was some amount of time ago - n as it is now".

Maybe math-talk isn't a good idea on a forum about English and liberal arts :p (it's the sevens you have to look out for, you know).
I'm a bit of a math geek and recall that Newton did some interesting stuff with really, really small deltas. But what are sevens?
 

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1. It has a lot to do with how active you are. I could jog in a t-shirt at 50 degrees and be comfortable--if I was just wandering around I'd be very cold.

Also has to do with who you are. 60 degrees F is the magic temperature when people in So Cal can break out their puffy down parkas and start complaining about the bitter cold. 60 degrees is also the magic temperature at which New Yorkers feel comfortable sunbathing in a bikini in Central Park. So is 60 degrees horrifically cold, or pleasantly hot?
 

Schilcote

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A mechanic??? Do you mean a parameter?

Sorry, another bit of jargon I didn't think hard about using. A good definition might be "anything the game does that affects the player's ability to achieve his goals". Shooting is a mechanic in first-person shooters, as is the ability to die. Units having different prices, Damage/Second, and ratios thereof is a mechanic of strategy games.

For a non video-game example, the values of the cards is a mechanic of poker, as is losing when you get 21 points, and the ace being worth two different values.

Temperature is a mechanic here because the player can get hypothermia or heat-stroke, and he needs to take steps to regulate his temperature in order to do what he needs to.


Perhaps also important are humidity and if there's any air movement (from a fan or central HVAC).

The simulation doesn't know or care about humidity or air flow, so luckily that's not a factor. Of course, those all really just affect delta-t again.

I'm a bit of a math geek and recall that Newton did some interesting stuff with really, really small deltas. But what are sevens?

The number after six. It's dangerous 'cos seven ate nine.

1. It has a lot to do with how active you are. I could jog in a t-shirt at 50 degrees and be comfortable--if I was just wandering around I'd be very cold.

Also has to do with who you are. 60 degrees F is the magic temperature when people in So Cal can break out their puffy down parkas and start complaining about the bitter cold. 60 degrees is also the magic temperature at which New Yorkers feel comfortable sunbathing in a bikini in Central Park. So is 60 degrees horrifically cold, or pleasantly hot?

Good points. Maybe I ought to scrap the temperature subjectivity idea after all, then- it could quickly become a pain in the butt to calculate.

And really, it doesn't matter all that much. I doubt anyone's ever died because they didn't notice the AC had crapped out and their house slowly heated up enough to kill them.
 
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King Neptune

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It is a very individual matter also. There are people who are cold at any temperature under 65, and other people who are quite comfortable with temperatures in the 30's.
 

Xelebes

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There are a few factors:

Wicking: Is the air moving around the skin, drawing heat from the body. When the air is still, the body generates a tiny heat bubble. When there is a wind, that heat bubble is harder to maintain. Winds can also mean that a mass of colder air is coming in.

Thresholds: If you step through a threshold of warm air to cold air, you will notice it (and vice versa.) You might shiver and you might experience a breeze that wicks in the threshold.

Wetness: The wetness of the air (moisture and humidity) determines how difficult it is to maintain or moderate that tiny heat bubble.

The person: there are several health conditions that make it difficult to manage the heat or the sensation of heat generated in the body.
 

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In answer to your question, people percieve a noticable change in temperature when they percieve it. That could be either physical i.e. walking form a cold room to a hot one, or traumatic eg blood loss. or shock through a non-invasive mental trauma.

cheers, niteshift
 

Cyia

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My understanding is that it has more to do with changes in temperature than absolute temperature- a person who moves into a room that's 5 degrees (Celsius) colder than the one he was just in will feel very chilly, but if you slowly lower the temperature of a room by 8 degrees its occupant might not even notice.


This is a variation of what's commonly called the "boiled frog effect." It's more true for the cold-blooded than the warm blooded. An 8 degree change Celsius is over 14 degrees Fahrenheit. Unless they're ill or unusually insulated, warm blooded animals, generally, will notice a shift that extreme.
 

boron

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According to certain standards, 18 °C (64 °F) is the lowest and 24°C (75 °F) the highest comfortable room temperature. It is a common opinion that 22 °C (72 °F) is the most comfortable environmental temp.

Brisk walking at 10 °C (50 °F) can make you feel quite warm and when you stop and sit down at that temperature you might need 30 minutes to start feel chilly. When you are at rest and move from a room with 20 °C (68 °F) to one with 10 °C (50 °F) you might feel chilly in 5 minutes.

If you are lying naked at 20 °C (50 °F) you can develop hypothermia after some time. People (often after drinking alcohol) have died from hypothermia in their own flats at temperatures about 10 °C (50 °F).

Your perception of environmental temperature depends on your absolute skin temperature. When the environmental temperature changes quickly, your skin temperature changes with some delay, so I don't think that the speed of temperature change has much impact on your perception of temperature.
 
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King Neptune

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It also depends on whether a givern person is endothermic or exothermic. I realize that all mamals are defined as endothermic, but I have found great numners of humans who don't seem to be capable of producing enough heat to keep from freezing.
 

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It depends on basal metabolism rate, which differs from person to person, under-skin fat stores, type and amout of food (or alcohol)consumed the given day...Some people probably become more resistant to cold after repeated cold exposure...well, I don't.
 

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This is completely individual, at least until you get into really extreme temperatures (we can probably all agree that 0 is too cold and 100 is too hot, but in between seems to be fair game).

I believe that any healthy young person should be able to adjust so they're comfortable in a very wide range of temperatures (at least 50-80 inside and 20-90 outside, with proper clothing, of course). Because humans didn't evolve with central heat and A/C, and I believe it's the overuse of those modern conveniences that makes people so wimpy about any temperature that isn't 70 degrees. I discovered this by accident when the furnace broke in my old house. We got space heaters so the pipes wouldn't freeze, of course, but it was impossible to keep it much above 58 or so in the height of winter. After a few weeks of misery, that started to feel normal to me, and I realized the outside temperature had become a thousand times more tolerable. There was no A/C the next summer either, and I soon discovered having it 83 inside makes the 90 outside much more tolerable too. And I save so much money keeping the heat on 58 and not using A/C in my new place. Now, if only everyone else would do the same thing so I didn't have to listen to them whine that 40 outside is "cold" and 80 is "hot".
 

King Neptune

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This is completely individual, at least until you get into really extreme temperatures (we can probably all agree that 0 is too cold and 100 is too hot, but in between seems to be fair game).

0F is not cold. It isn't cold until it is below -20F. 100 F is not uncomfortably hot. On that end the edge of comfort is about 110 - 115F.
 

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For a non video-game example, the values of the cards is a mechanic of poker, as is losing when you get 21 points, and the ace being worth two different values.

*pulls on poker knickers*

You meant blackjack, right? :D
 

boron

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A journalist has heard, the next day, in Siberia, could be minus 50 degrees Celsius. He thought this would be an interesting news, so, the next day he phoned to a random address in Siberia and an old woman responded.

Journalist: "Hello, ma'am, I've heard it will be very cold at your place today, would you mind to look up the thermometer and tell me what it shows?"

The woman goes to check and reports: "Minus 17."

Journalist, disappointed: "Hmm...I've heard it could be minus 50 outside today."

Woman: "Oh, outside, yes, outside, that's possible."
 
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ClareGreen

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I live in the UK. It doesn't get overly cold here, or overly hot; our wildest temperatures are still inside the 0-100F range. The men of Newcastle, the Geordies, are famed for possibly thinking about putting on a T-shirt when it gets to the point of freezing, while the men of Bournemouth are famed for putting on every piece of clothing they own when it gets that cold (or looking like they did).

With a variation like that in one small country with relatively mild weather, there is no one true answer for all peoples. The only real answer is that doing stuff or being in hot places makes you warmer, while sitting around or being in cold places makes you colder.

PS: Some of us do understand the maths and the video game references - we're not all liberal arts types (and my friend the actual Fine Artist understands maths and game mechanics too).