No. In the absence of behavioral effects such as the ones suggested here, the reason to have a single queue is not to reduce the mean time for a customer to check out, but to reduce the variance. With one queue per cashier, if you happen to get behind the person paying entirely with pennies, you're screwed. With a single queue, the additional latency introduced by such a customer will be distributed among all the customers who aren't being served yet, rather than just the few people behind them in the same queue.
Also, variance is what people perceive as bad service, not the mean time. If everyone takes a little longer they feel happier because of the perception of fairness.
I'd say a large bottle neck here is the employee base. If they factored in throughout into bonuses then they could get rid of many employees AND look good while doing it.
"New incentive to allow workers to make more then minimum wake"
I could already imagine the native ads!
I was very confident this idea would give better outcomes as I knew potential workers who could easily handle the higher load and do a better job at that.
Regrettably my idea was not used, and true to form, the leisurely pace of work was a drag on productivity. Twenty years later, long after I'd left that workplace, the outfit was essentially bankrupt and called out for mishandling funds.
I still think I was right, but even good ideas can be hard to sell.
Their model is probably less efficient during regular operation, but the variance when problems arise also seems lower.
As it was expressed to me the basis for the decision was that the "leaders" didn't believe the workers could handle the load as I suggested, so they went with their original plan.
At the time I attributed it to their rigidity but it could have been about relative salaries. Here I thought doing it my way would actually cost less when all added up.
It sounds like a trap. Move quickly, get higher scores for that, yet get reprimanded for poor customer service.
From experience, some customers are simply difficult to get to move on. You can do some things, but go too far and you wind up getting complaints about rudeness. It is all a balancing act.
Regular slow customers you can call for backup, if the place allows for that, but sometimes you are simply stuck.
Mathematically a single queue is far more efficient.
The psychology suggests that someone seeing a line makes them work faster.
First off, this is fleeting -- in a just a few years, we won't need people at the registers anymore as RFID technology gets cheap and more people become comfortable with the ever improving self checkout.
Secondly, even if you assume we will have checkers for a long time, this is again an easy problem to solve. You have a single queue, and then you make part of their pay based on average time per client or their evaluation. They'll work faster because of it (maybe).
A counterpoint to my own point is that Target does rate their checkers on efficiency, and I've watched them game it before. The checker meticulously lined up all my items with the barcodes in a row, then hit the "new customer" button, quickly scanned all the codes and hit the "total" button, giving him a very fast time. He figured out that they only measure from when he says "new customer" to total, so even though he was slower than everyone else, he had the fastest time.
But my overall point is that humans will soon be out of this loop anyway.