Chomsky (2014) argued that grammar monopoly is an effective way to highlight first language interference.
I know, I know. 2014 is past and finished, so you want to use past simple tense. However, in this case the currency of the idea – is it recent and/or valid? – is more important than when it was written.
The currency of an idea can occasionally be difficult to determine, but in most cases it is obvious. If we assume that Chomsky is still alive (as he is at the time of this writing) and that his idea is still current then we use present simple tense, even if the idea was written in the finished past:
In most postgraduate writing we are dealing with current ideas, from recent sources, and so most of the time you will need present tense for your reporting verbs.