This is an interesting question and subject to debate, for decades. The concept "hub sciences" (or center sciences), can also be interpreted according to Mardones (1991) as "natural sciences" as opposed to the so-called "spirit sciences", a direction that Karl Popper established when referring that "our purpose is to establish the truth of the theories, we must experience them as severely as we can; that is, we must find their faults, we must try to refute them "(Mardones, 1991, p.92)
John Cacioppo (2007) has made a remarkable reflection on which sciences can be consider of center or (hub science) and the location of psychology as part of this set (clearly J.Cacioppo, considers that psychology if it is part of this conglomerate).
From Popper and Compte among others, psychology belongs to the sciences of the spirit, but not to the natural sciences. Strictly speaking, given the methodological differentiation (extensively explained by Popper), the methodological rigor and the relative subjectivity of the results of the investigation, as well as its interpretation, in contrast to the position of John Cacioppo (2007), this area of knowledge It should NOT be considered a "center science " or natural science. At present, however, this point of view is debatable, because although their method is not the "traditional of the natural sciences" there IS a method, hypotheses formulated and tested and they seek and achieve as well as those that refute or accept, as well as generalize the results of their investigations, as Popper suggests, a science must do.
The map proposed by Boyack, KW, Klavans, R., & Börner, K. (2005) gives us a broad idea that "sciences" are close to this taxonomy and which are far (and could therefore not be considered a hub science or discipline)
Strictly speaking and as John Cacioppo (2007) points out "seven hub sciences are identified: mathematics, physics, chemistry, earth sciences, medicine, psychology, and the social sciences". Answering your question, those disciplines not related or derived directly from this list could be excluded (or not considered) as a hub science (or related discipline); Such is the case of law, political science, and economics which all lie along the outside of the backbone map.
Greetings and great question!
Words:366
Keywords: hub sciences, scientific method, Karl Popper, John Cacioppo.
References:
Mardones, J. M. (1991) Philosophy of the human and social sciences. Materials for a scientific basis. Barcelona. Anthropos
Boyack, K.W., Klavans, R., & Börner, K. (2005). Mapping the backbone of science. Scientometrics, 64, 351-374