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> 目を **輝かせ** てアメを作っていたおじさん。  
>  The man with sparkling eyes who made the sweets.  
>  期待で目を **くりくりさせ** ながら...  
>  While wide eyed in anticipation...

Both these clauses use a causative form of a verb to describe a person's eyes.

In English when we use caustive to describe a person's expression it means
that they deliberately made that expression. Whereas these sentences sound
like the expressions are natural/spontaneous.

1) Would these sentences be wrong if I just used the plain form of the verb?
If not how would the nuance change?  
2) Is there a way to know when I should use causative for something like this?
It's not at all intuitive to me.  
3) What other things can be described by this structure? Is it limited to
eyes, facial expressions, any body gesture, an even wider scope?
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2017-05-20T16:18:10.100
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2017-05-21T01:37:18.463
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question
grammar causation
Causative verbs in descriptions of people
Besides 目を輝かせる , a couple more such expressions come to mind:

目を細める "narrow one's eyes" (often in a good way - that is, smile kindly, look
at [a baby] fondly] (ほそめる is one of those causatives made by adding める to the
root of an い adjective, in this case ほそい)

耳をすます "make one's ears clear" - that is, listen carefully

I don't think any of these suggest the expression is adopted deliberately
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2017-05-20T18:13:19.780
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1) No. 目を輝かしアメを作る、目をくりくりしながら、both constructions are OK. By the way this くりくり
usually indicates "the eyes are moving actively and/or are wide open."

2) In my opinion, there are little differences even in nuance, but the
causative make the sentence a bit less "descriptive(I don't know this word
make a sense)". The Japanese causative action doesn't have to be
"deliberately" or not even "voluntarily" caused. e.g.
彼は癲癇(epilepsy)で手足をヒクヒクさせていた。

3) Do you mean the causative by "this structure?" If so, everything.
戦争は多くの難民を発生させた。新情報は会社の新たな行動を控えさせた。
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2017-05-20T23:54:22.750
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2017-05-20T23:54:22.750
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answer
1) 輝いた目でアメを作っていたおじさん and 期待でくりくりした目で would be understood, but they are a bit
less natural.

2) I feel many of them are idioms or established set phrases, so perhaps you
just have to get used to common ones.

3) It's not limited to facial expressions.

  * 口をとがらせて反論する
  * 鼻を膨らませながら怒る
  * 期待に胸を膨らませながら考える
  * 緊張で足を震わせながら報告する
  * [肩を怒らせて](https://kotobank.jp/word/%E8%82%A9%E3%82%92%E6%80%92%E3%82%89%E3%81%9B%E3%82%8B-463206)歩く
  * [首を長くして待つ](https://dictionary.goo.ne.jp/jn/62670/meaning/m0u/) (eagerly look forward)
  * 息を弾ませながら話す
  * 汗を滲ませながら走る

There may be similar actions which are not related to body parts, but such
actions would probably be expressed with causative forms in English, too.
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2017-05-21T01:37:18.463
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answer