How do dwarves age relative to humans?

Question

I'm trying to figure out how dwarves in dungeons and dragons, mainly in lore, age relative to humans, specifically behaviourally?

My preference for lore references is the Forgotten Realms but if there is not enough information there, I'd accept from the Dungeons And Dragons franchise as a whole.

I'm specifically looking for direct comparisons of dwarves to humans, again mainly in lore. So any passage from rules or connected novels etc. that say something like "Diggy McMineface was 18, a baby to others dwarves, but as capable as any human the same age", or "Although she was not considered mature by the Dwarven elders, Diggella had finished her apprenticeship in pie-making at the same age as other dwarves, 12".

This is largely as the D&D 5e basic rules say, for Dwarves:

Age
Dwarves mature at the same rate as humans, but they’re considered young until they reach the age of 50. On average, they live about 350 years.

But for a start, I couldn't find an 'age' section under the Human entry on DnDBeyond, second the concept of being an adult varies wildly by culture and time in the real world, especially as adulthood/maturity are often overloaded terms, being anywhere between 11 (the age children were sent to workhouses in the 19th Century) and 40 (the age of candidacy in many countries).

And secondly, "considered young" by whom? Other dwarves - obviously - but which ones? But if I'm comparing to humans, who they consider the behaviour of 18 year old dwarves mature, and it's only dwarves and other long lived races who'd consider them them immature?

So are their applicable comparisons of dwarven maturity behaviour (expected or average) with humans in lore?

I think a different, but equally valid phrasing, what happens between 18 and 50 to a dwarf that shows maturity compared to humans?

Answer 1

You have quoted one of the relevant sections (for Dwarves). The relevant section for humans comes from the PHB, in the description section titled "A Broad Spectrum":

Humans reach adulthood in their late teens and rarely live even a single century.

The relevant quote for dwarves is:

Dwarves mature at the same rate as humans, but they’re considered young until they reach the age of 50. On average, they live about 350 years.

Taking these two sentences in concert we must conclude that physically dwarves are "adults" by their late teens, but they are considered "young dwarves" until they are age 50. As to who would consider them "young", it's clearly other dwarves.

Being considered "young" is an inherently cultural thing and may have a variety of meanings, such as:

1. They might be immature in personality or experience.
2. They might be rash or hotheaded as a result of their comparative "lack of experience" compared to other dwarves.
3. Their might be certain things they don't get until they are no longer "young" (for example, some clans might not give their "young" a clan name)
4. They might not be considered an adult until they are no longer "young"

The explanation of racial traits, and age specifically, in the PHB points is in the right direction:

The age entry notes the age when a member of the race is considered an adult, as well as the race’s expected lifespan.

So for the purposes of the game, we can now interpret the Dwarf age racial trait as

• A dwarf is not considered an adult by their society until they reach age 50, however they are physically mature by their late teens. Their average lifespan is 350 years.

Answer 2

Life history stages were well-defined; the culture aspects of age not so much

More than any other edition I believe, first edition (AD&D) broke up lifespan into different categories and assigned names to these categories.

Child
Human 0-13 years
Hill Dwarf 0-34
Mountain Dwarf 0-39

Young Adult
Human 14-20 years
Hill Dwarf 35-50
Mountain Dwarf 40-60

Mature
Human 21-40 years
Hill Dwarf 51-150
Mountain Dwarf 61-175

Middle-Aged
Human 41-60 years
Hill Dwarf 151-250
Mountain Dwarf 176-275

Old
Human 61-90 years
Hill Dwarf 251-350
Mountain Dwarf 276-400

Venerable [upper age venerable is the maximum lifespan]
Human 91-120 years
Hill Dwarf 351-450
Mountain Dwarf 401-525

These rules were used by Ed Greenwood for his home campaign that would become the Forgotten Realms. The categories themselves were reduced and simplified for the 2nd edition rules that roughly coincided with the publication of the Forgotten Realms campaign setting.

Further, the reduced age categories were explicitly tied to maximum age, such that it appeared as some sort of natural law that while the races aged at different rates, their passage through the age categories occurred at proportionally the same rate. That is, Middle Age began at one-half the racial maximum, and Old Age began at 2/3 the racial maximum.

Human: 45 years (Middle age), 60 years (Old), 90 years (Venerable)
Dwarf: 125 years (MA), 167 (O), 250 (V)

PC's were assumed to start in the Young/Mature age category with the ability scores they had rolled at character creation. For each subsequent age category they passed through, their physical scores (Str, Con and sometimes Dex) declined, while their mental scores (Int and Wis) increased.

The categories certainly implied changes in personality and behavior with maturity, but these were not spelled out in that section of the rules, but rather to be found in the lore of the different races. Thus, a young adult human and a young adult dwarf would both be considered immature by others of their own race. But how that immaturity was reflected in their personality would be different, and would be shaped by both their nature and cultural norms. So, for example, immaturity in a human might mean impulsivity, rashness, disrespect of authority. A dwarf, strongly Lawful by nature, would be none of these things - but might when immature focus more on their individual contributions to the clan ('I want to be the best smith' or 'the most renowned warrior'), rather than the collective contributions they valued as they matured ('I need to help organize the miners better so we can pay the bride price for Thorbold to marry').

While the age categories themselves were very well defined, it seems like most of what you are looking for, the cultural nuances, are not in the rulebooks themselves (PHB and DMG). Rather, they would be spread out among all the other sources of lore, like the 'Point of View' articles in Dragon, NPC descriptions in modules, and so forth. As such, they had multiple authors, little overarching themes, and were sometimes contradictory. Compiling them would be a serious academic endeavor.