There is a risk of evolutionary arguments becoming circular: crudely put evolution is the survival of the fittest, but the only measure of what is the fittest is what survives. Some have even gone on to say that Darwinian theories of evolution are not truly scientific because of this.
So such speculation about the evolution of illness behaviours and societal response to long term conditions, albeit very interesting, may struggle to get beyond descriptions of varying degrees of accuracy unless one can get to the point of being able to make testable predictions.
Indeed. However the evolutionary idea does give one possible explanation to the awkward detail that subjective surveys often produce positive results not matched by objective measurements.
Accepting subjective answers at face value, without any consideration of how they may be skewed by other influences, is a much worse error in my view. Especially when objective measures suggest a very real bias towards optimistic self reporting.
The reason for the discrepancy may not be evolutionary, it may be a more recent cultural phenomenon, or simply a bias introduced in the way the questions are asked, but all of these are worthy of discussion, because they affect our choices about what we should be measuring.
In my view, objective measures are key, and subjective ones can only be a useful proxy if (and only if) they have been demonstrated to effectively match a relevant objective outcome.
So yeah, I agree we cannot easily confirm why subjective outcomes tend towards the optimistic, but we can discuss the many possible reasons. By doing so we remind ourselves, and others, that what people say is very subjective, and rarely a truly accurate picture.
Of course what we say might be swayed to the negative depending on our mood (or circumstance) but apparently this is less likely, and the most frequent bias seen is towards overly optimistic reporting.
So why is that? Perhaps it doesn’t matter why, only that we acknowledge that it does.