“Imagine this scene. There are six people in an elevator with an actor hired by researchers. The actor drops a bunch of coins and pencils. They fall to the floor with a clatter. And then, as the elevator goes down floor by floor, not one person moves a muscle to help. The people in the elevator have to notice the actor picking up the coins and pencils on the floor. But each person is surrounded by five others who are doing nothing. If the people knew they were being tested, every one would instantly come to the aid of the stranger.”
* source; ‘The Hidden Brain, How our unconscious minds elect presidents, control markets, wage wars, and save our lives.’ by Shankar Vedantam
I think the underline part is in a subjunctive mood – the second conditional. If so, I wonder why the author wrote “they were being tested” instead of “they are being tested”, since I feel the ‘knew’ is a counterfactual conditional but the event - ‘a test is being done’ is a factual one. I mean the subjunctive mood can’t be extended to the other verb in the subordinate clause depending on the context, especially not allowed in the sentence above.
Your response would be much appreciated.