What do ability scores values mean

[DarthPenance]

Well, this is from a more roleplay perspective, I know that the average human ability score is 10, but what about the ones above and below and what does average mean, average as in what?
For example would someone with a 20 in intelligence be considered a super genius that the ones with average and below wouldn't be able to even comprehend, but if one has 6-8 intelligence how would they act? Would they be illiterate or have some kind of mental slowness. The physical abilities are more easily explained, but how would you compare to real life appearences?
This one is more of a curiosity, but does charisma affect beauty or is affected by it? If so, would someone below 10 be considered ugly?
Sorry if the doubt is stupid and if there are too many questions, it would help picture my character and how to roleplay his ability scores and not mine's.

[Sicarius Victis]

Charisma is less "physical beauty" and more "force of personality". Why do you think Intimidate is Cha-based?

[RedWarlock]

Int has been said to equal 1/10th your IQ. So someone with an 8 int would have an IQ of 80, while a 14 is a 140. (This is an old standard, but it's a good rule of thumb.)

Charisma is more remarkability than attractiveness. A low-cha character is plain, whereas a high-cha person could be gorgeous or hideous, but either way you *notice* them, they radiate a social energy.

Strength has been said to be what you can press over your head, divided by 10. So a 14 Str character can lift 140 pounds over their head. (I'm a weightlifter, and I can lift 200 pounds, according to a 1-rep max calculator, so I have 20 Str!)

[SilverStud]

As a DM, I've had a lot of players RP the stats in different ways. Your question is pretty relevant for people who want their character sheet to matter a bit more.

If I were to stat out myself using those stats, it would probably look like this:

STR 11
DEX 12
CON 10
INT 12
WIS 10
CHA 11

Given that I am a large man, I'm slightly (slightly) stronger than the average American. I'm good with my hands and fine motor control, have a normal immune system, am a skilled programmer, have normal common sense, and a forceful personality.

The way I see it, if I worked out I could give myself a 14 STR, and if I practiced fencing or something I'd get up to like a 14 DEX.

I mention all of this to put the stats into my perspective.

Mental stats, as you said, are different. The toughest thing for people to figure out is how to roleplay dumped INT but high WIS (like a druid or cleric). For some reason I see so many people RP low INT by adopting slow speech and a caveman voice. But what about that high wisdom???? I have a player who I feel is doing a very good job with it.

He's got 10 Wisdom (normal) but 7 Intelligence. Instead of playing a caveman (which would be wrong, IMO), he plays a character that simply knows what he wants and doesn't think too hard about it. He goes with his feelings, because his brain just slows him down. He still is easily smart enough to function in society (unlike a caveman), but forgets details of things rather easily.

It's best to decide what you feel your character would be like and then match his/her stats with that. If you find yourself going the rout of Stats-then-Character, remember this:

Strength: Can crush stone tomato
Dexterity: Can accurately throw tomato
Constitution: Can survive eating bad tomato
Intelligence: Knowing tomato is a fruit
Wisdom: Not putting tomato in a fruit salad
Charisma: Convincing everyone tomato goes in fruit salad

If you have low intelligence but just found out they are a fruit, you still wouldn't put one in a fruit salad, right? Low INT doesn't mean you're an idiot. It just means you're not so great at deduction and memorization.

[Millstone85]

Have you noticed that characters of Str 8 or below can not manage a punch, like at all?
Their unarmed strikes do 0 damage on a hit.

[Falcon X]

Charisma is less "physical beauty" and more "force of personality". Why do you think Intimidate is Cha-based?
I agree. Though something has to also account for why Charisma is used for Sorcerous spellcasters and certain other things. Two additions come to mind:
1. The word "charismata" is a greek word for "gifting". It could also apply to a person's natural, innate abilities.
2. It could also apply to how well a person can communicate with spirits.

[rbstr]

I think that Cha-magic works in that Charisma is, in some ways, your force of will. Like some people can manage to get things done simply by telling people "Do that thing" with a certain inflection or they say "I'm going to do this" and succeed even if they don't really have more than a longshot by trained eye..
That's what you're doing to magic as a Charisma Caster.

[LudicSavant]

The best way is to not think of attributes separately, so much as to think of your specific capabilities. Why are you able to make DC20 Survival checks most of the time? Make up whatever reason seems like an interesting fit for your character. Proceed down the list until you've accounted for everything you can do.

Tying too much assumed fluff to an attribute value limits the range of characters you can represent, as well as occasionally creating some really wonky situations because the assumed attribute fluff of many players often doesn't match what the attribute really does (for example, Strength is not a raw ability to lift things, even though it influences your ability to lift things. Two characters with the exact same strength score may be able to lift a very different amount of weights based on factors like, say, their size category).

The pitfalls of placing too much emphasis on attributes rather than the things they modify is even more apparent in older editions, where you would frequently see things like, say, a person with 8 Charisma and +35 to all social checks, or a character with 8 Constitution who had a fortitude save so high that they could brush their teeth with Black Lotus Extract every morning, and rinse with Purple Worm Poison, and then jump off a 200 foot high cliff and get right back up. And then you'd have someone say "But 8 Constitution is lower than average, and therefore he's frail and sickly!" Which just... completely ignores what's actually being represented by the mechanics in-world.