Is there a difference between 显得 and 看起来？ Recently, I've been reading a short story writting by 丁玲 and I noticed she often used the term "显得" where I would have said "看起来”。 I'm trying to figure out when I should be using 显得 vs. 看起来. It seems like 显得  is more formal, but are there any other distinctions? For example could I say 
"我一看到他， 显得很开心 “ 
or 
” 这个脱口秀显得很好笑“  

Thanks for the help!
显得 sounds a little more formal than 看起来, but both are fine to use in spoken and written contexts.
Their meanings though, are not completely the same. Both words can be used to express to seem; to appear; to look. With this meaning they are interchangeable and the difference is mostly formality:

他显得很憔悴 / 他看起来很憔悴。He looks haggard.

But both words can be taken 'literally' - 显得 means (actively) present oneself as while 看起来 means (passively) be seen as. When used in this way, they are not interchangeable. E.g.

这个节目看起来很好笑。&lt;-- 显得 would sound unnatural because people find the show funny, not the show presenting itself as 'funny'.
他故意显得很愤怒。 &lt;-- 看起来 is acceptable but 显得 is much better because it is consistent with 故意. The sentence means 'he was trying to make a point by appearing angry'.