Something I didn't understand about van de graaff generators.

I was reading about an experiment in which objects (neutral, I believe) are attracted to the generator a few seconds after it is switched on. Apparently, after they touch the generator, they then move away. 

I believe I understand why the neutral objects are attracted to the generator; the charged generator repels the same type of charges to itself from the surface of the objects, leaving only the opposite charge at the surface, and therefore inducing a temporary attraction. 

However, why do the objects then fall away? Is it to do with the charges dissipating when they touch another object ie. the generator is earthed? Or does the charge from the generator flow into the objects, giving them the same charge and so repelling them? I presume its the latter, but I would like to be sure.

Thanks in advance.