determiners - psychologist John Hayes (THE, zero article before false titles)

An example (from The New Yorker) of a phrase with a false title (psychologist John Hayes):

After Simon and Chase’s paper, for example, the psychologist John Hayes looked at seventy-six famous classical composers and found that, in almost every case, those composers did not create their greatest work until they had been composing for at least ten years.

Both THE and the zero article could be used with false titles, but which looks better in this sentence to a native speaker? Would this look OK:

After Simon and Chase’s paper, for example, _ psychologist John Hayes looked at seventy-six famous classical composers and found that, in almost every case, those composers did not create their greatest work until they had been composing for at least ten years.

What if we beefed up the phrase with an adjunct? Would 0 and THE both look fine?

After Simon and Chase’s paper, for example, (Ø/the) cognitive psychologist John Hayes looked at seventy-six famous classical composers and found that, in almost every case, those composers did not create their greatest work until they had been composing for at least ten years.

After Simon and Chase’s paper, for example, (Ø/the) American cognitive psychologist John Hayes looked at seventy-six famous classical composers and found that, in almost every case, those composers did not create their greatest work until they had been composing for at least ten years.

It seems that THE looks O.K. when a false title is short ("psychologist") but starts looking strange before some complex combinations.

Answer

When both options are acceptable, it's very hard (if not impossible) to tell which would "look better" without larger context.

To me, they both mean the same thing, however the emphasis is slightly different. In this particular quote, with the ∅ article, a bit more emphasis seems to be on the name of the individual:

After Simon and Chase’s paper, for example, psychologist John Hayes looked at seventy-six famous classical composers...

With the definite article, though, some of the emphasis seems to shift to the title:

After Simon and Chase’s paper, for example, the psychologist John Hayes looked at seventy-six famous classical composers...

So, if you're more interested in conveying who did the study, perhaps the ∅ article would work slightly better. On the other hand, if you want to emphasize that person's field of expertise, then it may be better to include the definite article.

In this particular instance, that latter option might work well when researchers from several different areas studied the problem – psychologists, human factors engineers, social scientists, anthropologists, etc. – but you want to emphasize this was a psychological study. However, the former might work better if several psychiatrists studied the problem, but we were interested only in examining Hayes' findings.

It should be noted this is difference is very, very subtle, and not all readers may not interpret it in the same way. I'm not giving rules to be dogmatic about, I'm giving considerations to ponder. I will stand by this one point: you can't always tell the best option when you look at only a single sentence; you need to look at what else is in the paragraph, and even what else is in the surrounding text.