[From Bruce Abbott (951002.0855 EST)]

Mary Powers 950929 --

The tantrum is for the purpose of control. Tantrums usually are.

Two-year-olds don't have a lot of other ways available to them.

Yes, and one of the things we expect kids to do as they mature is to
suppress such behavior when otherwise inclined to do so, even when that
means that the perception the tantrum serves to control must remain (at
least for now) out of match with its reference signal. This is, as I view
it, different from learning other control strategies. As these "other ways"
become available to them, children have less need to use the tantrum, but
the ability to suppress the tantrum even though there is no other way to
succeed is at least part of what we call self-control.