I am skeptical about these results. Bias of the experimentor tilting the results cannot be dismissed.

But even if we assume the experiment and results to be perfect, then all we can say is that a dead person appears, on average, to be 21 grams lighter.

Nothing more.

Attributing this mass to a ‘soul’ is wishful/magical thinking.

It also betrays that the experimentor assumed the existence of the soul prior to the experiment.

The fact that he wasn’t surprised that the dogs didn’t loose any mass, again betrays his bias towards a religious (ill-defined) concept of ‘soul’.

The experiment does not establish a link between mass and ‘soul’.

We can also attribute the loss of mass to personal flying rastafari teapots.