I subscribe to the "Motherlode" blog  via Google Reader, and was interested in "Paying Kids to Be Good".  There was a fair amount of confusion on the comments board about how Lisa Belkin's reward system worked; some immediately understood that it was set up like the Prisoner's Dilemma, while at least one seemed to be under the impression that it went: children misbehave -> parent offers bribe, so that the children would misbehave any time they

wanted a bribe.  So much for the reading comprehension skills of the internet public.

There was also an ongoing debate about reward vs. punishment for dealing with misbehaving children on the comments board; however, you can set up this system so that it's either reward *or* punishment, like so:

Punishment. The child's weekly allowance is $10.  For each day either child misbehaves, they each lose $0.50.  For each day the child misbehaves more than their sibling, they lose an additional $0.50.

Reward.  The child's weekly allowance is $3.  For each day the child misbehaves less than their sibling, they get $0.50.  For each day neither child misbehaves, they each get another $0.50.

The same behavior in a given week leads to the same allowance, and it seems to me that the one the children respond to best is situation-dependent.