The 1968--1972 cents had a lot of Machine Doubling on the cents those years. Yours is another example of this. Did you know that that the big DDO that year has most examples that had Machine Doubling on them? Here are 4 examples:
Note the dates are all doubled dies, but do you see the yellow arrows. That is where the Machine Doubling reduced the sizes of these devices. It is not the machine causing the doubled dies, but the dies that are created with the doubled hub issue that are what strike doubled dies. Well just as a normal die struck your coin and after the strike, the machine damaged the affected devices, this can also happen to a doubled die as well as the machine causes the damage after the strike. Again note the yellow arrows, there is your proof that the machine causes this damage to the devices, where as the die strikes doubled dies. Thus the reason we call them that. They are doubled die, because the dies are doubled.