Slight tilt from center line
I would think that a shooters accuracy would be off slightly if all the students sat with their arms straight up and just at the moment the shooter begins his final motion to shoot, tilt slightly to their right maybe 6 degrees (the shooters left). This slight distortion at the last minute would challenge the brain to adjust for background distortion and complicate the shot. The motion must be executed at the last possible moment. Otherwise, the brain will have already executed its response to background distortion. The brain reacts in fractions of a second. So, the opportunity is small, but relevant. The same effect would be to move the arms backward or alternatively forward, creating mental confusion of distance during the actual pre-release moment.
Thinking of how the brain actually sees, if the students around a circle of maybe 10 feet diameter directly in line with the shooters view of the basket did nothing and the fans around them made the pre-release illusion, the brain would have difficulty at the last moment to interpret what it was actually seeing at the basket. One eye would be suggesting motion, the other would be suggesting no motion. The brain would be seeing tilting and no tilting at the same time. How the brain could reconcile this visual discontinuity would create the best condition for mental distortion in my opinion.
Reversing this on the second shot would add additional complexity to the brain to overcome.
