If I am not mistaken, that entity or entities, should it even exist in a form that can be remotely comprehensible to us, has been around a good, long while; and, as a "scientific being" itself, it most likely does not take too kindly to us lower life forms who would question its motives or methods.
That said, the concept of "responding to stimuli," is often a chicken or egg problem. And, as we humans will often take many liberties with such things, and never seem too shy to snatch defeat from the jaws of victory - so it is with modern medicine, wherein, we often equate the concept of being permitted to apply names and labels to people and things, with the need to do so. And thus, in an effort to be relevant, we create entire dictionaries of terminologies that apply to "personalities," and the parameters which might characterize or influence them - all the while, oblivious to the fact that, though we are simply using our little labels to sound erudite in our communications - someone else is using them to do things like deny someone health insurance coverage, refusing them a job, or otherwise spreading misleading information, and so forth.
For the above sorts of reasons alone, as well as others, one might wish to consider the possibility that "personality" may be one of those things that, while we can spend an eternity attempting to understand it - the case may be that our energy is far better spent in simply noticing our own "p word," and then enjoying it as much as possible, absent any additional classification.....