There are several spoilers in this post****
try this potion: cactus, lotus, black orchid
I send three children off to collect the herbs, then, once they are done, I drag my cheif over to "lecture" which gets all my villagers in one area. Then, while he's doing that, I take one scientist over to mix the potion. When he's done, I hit pause (spacebar) and drag every villager over and drop them on the pot (make sure their status changes to "drinking potion") then unpause (spacebar again). They'll all say "must exercise!" and start running around (if you have lots of villagers, this can be very entertaining

). After about two minutes, they will stop and either say "no" or "mm-mm" or will gain some building skill. After doing this about twice (three times for stubborn ones) they should be at "trainee builder". At that point you can drop them on the statue (only if the cheif is "directing work") and they will work on moving the statue

most of mine were master builders by them time the statue was done.