I've tried them all and have found varied success. I do have two observations that steered me away from looking at the dots:
(1) I have found is when I look at the dots, I find myself jamming the ball into the lane. Looking at the dots, you get a false sense of security in that you hit your mark and the shot is done, so there may be many a time where you find yourself not following through and "short-arming the ball". I have done this and many others that I have come across.
(2) A miss at the dots is significantly multiplied down the lane. We are all going to miss, that's a given, but the closer your target, your miss becomes larger downlane. I'm not sure of the exact numbers, but missing by one board left at the dots will cause a greater affect than by missing one board left at the arrows, and even more of an affect that by missing by one board at the breakpoint. It's like a risk/reward factor. The closer the target, the less risk you have of missing it, but if you do miss it, the consequences are severe.
I understand that to each is own, and there are definintely times when the shot may call for you to look at the dots to force you to get the ball down early or some other reason, but for the average bowler on the average/modified house shot, I would recommend looking downlane, I think that in the end it can only better your game.
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Why does everyone try to make it harder than it really is? Overthinking makes the game that much more difficult.