You probably saw some rising happen in the straws containing Control dough. This is because flour is a starch. Starches contain glucose, a form of sugar (this is why a saltine cracker tastes a little sweet if you let it sit on your tongue for a while; the enzymes in your saliva break the cracker starch down into glucose and other simpler molecules). So even though you didn't add any sugar to the Control dough, it already contained some for the yeast to munch on. However, because the amount of sugar in this dough was much less than in the others, less carbon dioxide could be made by the yeast in this batch and the dough couldn't rise as much in comparison.