I think all y'all skeptics are forgetting that this test, while performed with particles, demonstrates the properties of a WAVE. The spin of the electron, amplitude or lambda of any ridiculousness some of you are suggesting, or anything else is affecting the pattern created when the experiment was left unobserved. What we see is the product of wave-interference - which is a physically observable pattern that you can create in a home environment by bouncing two balls next to each other on the surface of water. And yes, the very act of observation IS what changes the results; Erwin Schrodinger was able to demonstrate this with his thought experiment. ALL quantum particles behave the way that the electrons did, which is the basis of qunatum uncertainty and wave-particle duality.