How to use "Think" and "Mix up" when reporting news?

Question

Several resources indicate that present perfect tense is preferred to give new information/hot news therefore that's why we see present perfect in the news and on the newspapers (such as "The prime minister has resigned", "The athlete has broken the world record" etc)

When giving hot news, do we use present perfect considering current relevance semantically or do we just focus on the fact that action happened in recent past?

Allow me to demonstrate my question with regard to some confusing verbs for me which are "to mix up" and " to think"

Example 1-Giving new information to someone

A: Tell me how did it go?
B: I've mixed up Jessica with somebody else. I couldn't give her your letter. Then I recalled her face but it was too late.

Example 2-Giving new information to someone

A: Tell me how did it go?
B: I've thought the blonde girl in the hall was Jessica. Apparently she wasn't. I couldn't give her your letter. Then I recalled her face but it was too late.

Example 3- Reporting the news

The prime minister has mixed up finance committee member with tourism committee member.

Example 4- Reporting the news

The prime minister has thought Mr. Mike Jones was from tourism committee.

On examples 3 & 4 mixing up is over too and the prime minister knows the correct committee member now which is also known by the reporter.

Can you please inform me whether using present perfect is correct in all these examples focusing on the fact that mixing up action happened in recent past? Or should simple past be used?

Answer 1

Your source is correct and it is common for journalists to report recent events using the present perfect, in things like newspapers and television news programs.

Today the Prime Minister has announced that he was going to try to reduce taxes.

This is not common with non-journalists just talking about recent events.

Did you hear that the PM announced today he was going to try to reduce taxes?

Even then only for things like statements, policies, or actions that have ongoing effects. Journalists would not use this for isolated events:

There was an embarrassing moment today when the PM mixed up a finance committee member with a tourism committee member. The gaffe was quickly smoothed over by his aides, and the meeting went on as scheduled.

Otherwise your examples do not depend on "reported" speech, but rather when to use the simple past and when to use the past/present perfect (a common question on ELL).

Native speakers tend not to use the perfect tense when the simple past will do. As in your example with the letter to Jessica, if all of these actions take place in the past, and are sequential but not otherwise dependent on each other, the perfect tense is not needed:

I mixed up Jessica with somebody else. I thought the blonde girl in the hall was her, and only recalled her face too late to give her your letter.

You could use the past perfect, if the later event was related to the earlier event.

I had mixed up Jessica with someone else, but I was able to recall her face in time to deliver your letter to her.