What is the difference between using 很, and duplication of the Adjective?

Hello Mike,

I think both are different ways of emphasizing something or confirming it.
One is by using "很" and the other by repeating the adjective.
The peculiar way is to use the adjective twice to emphasize something.
However their connotation are almost the same, they both emphasize the quality of something.

不好意思，打错一个字。“这道菜有点辣辣的”

Hello Mike
ok,Mike ,this is a difficult question to answer.hehe,but i 'll do my best to answer it.
there are two situations。
The first one :Mostly ,there are only girls say "辣辣的”。the duplication of the adj.contain a meaning just like some girls are coquetrying.I think it's a little strang for boys to say some duplication of adj. words.
ok,there are some other words like this,“美美”
the second one,We can say the duplicatian of adj. is more emotional, but the 很 is to express a strong feeling.look thess two sentences below:
我慢慢的走。Vs 我走的很慢。
o(n_n)o...Sorry ,it's too difficult to express it in English.haha .

As far as what I feel,the "很”or“非常” is as same as the Enlish words pretty or fairly.Instead,the duplication of the adjectives is not a very common phonomenon on daily basis.In the most of cases,it's used colloquially.Its function is kind of like emphasizing like what you said"辣辣的“.Another function is to try to show some sort of "adorable" feeling towards the person or the object you describe.Like "胖胖的 傻傻的”.In the formal articles,these functions mostly disappear.It just represents the literal meaning.

Hi, Mike
很辣means very hot
辣辣的is kind of a cute expression to say slightly hot. It's more of the language of children and girls. Generally, men wouldn't say that. Its neutral expression would be有点儿辣.