Does the mannequin have the ability to make itself seem heavier at times as children do?
Geez, even I know to use a papoose!
My son at about 9 months of age would arch his back during tantrums, roil around like an acrobat, and learned to do flips to try to reach things behind him or to get put down.
Their test is not accurate as the stress load of “carrying” a young child.