There is no experiment which proves its false. This is the problem with pseudoscience, it's "not even wrong".

Psychometrics presents summaries of data as if they are properties of reality. As-if taking a mean of survey data meant that this this mean was a property of the survey givers.

This applies only in extremely controlled experiments in physics, and even then, somewhat rarely.

All one has to do to show the entire field is pseudoscience is present a single more plausible theory than "mean of data distribution = innate property", and this is trivially done (eg., cf. mutualism about intelligence).