I have to admit it Doc, I just don't get this one?
The point is that when the pigeons were placed in a situation where their actions could not affect their environment, they adopted a set of entirely pointless rituals which they thought (insofar as a pigeon can be said to think, Skinner would turn in his grave)
did effect their environment.
We might compare this to such things as prayers for rain, sun dances, intercessionary prayers for the sick, and so forth (if these things do in fact serve no function).
You may reply that humans are not as dumb as pigeons, and of course I agree, but we are just about as intuitively poor at knowing when there is and when there isn't evidence of a causal correlation when presented with statistical data.