Sure, there is subjectivity in the ways researchers operationalize the concepts that they study. That doesn't mean that their research is not "real science". If the study is of sound design and the result is replicable, it ought to be called science.
Regarding the self-measurements influencing the results: the wisdom in the participants' reasoning (the dependent variable in the focal study) was evaluated by two independent hypothesis-blind raters. This seems like a pretty solid evaluation of the participants which should be immune to anything but the manipulation the researchers employed (the diary conditions). I am not sure what self-measurement you are concerned about.
Regarding the self-measurements influencing the results: the wisdom in the participants' reasoning (the dependent variable in the focal study) was evaluated by two independent hypothesis-blind raters. This seems like a pretty solid evaluation of the participants which should be immune to anything but the manipulation the researchers employed (the diary conditions). I am not sure what self-measurement you are concerned about.