You rightly point out that there are many models of organisational structure. Models are useful as signposts to general structural attributes, but often they are descriptive in nature and do not explain how the processes operate. I’m afraid that you misunderstood my question, and it is an important one because it helps locate theory that may explicate those processes. Please allow me to expand a little on this idea.
Psychology investigates the individual; their motivations, attributes, traits and so on. Sociology is, well let me offer Max Weber’s own definition as it is infinitely more eloquent;
“the science whose object is to interpret the meaning of social action and thereby give a causal explanation of the way in which the action proceeds and the effects which it produces” (Weber, 1978, p. 7).
The unit of measurement is the group and the topic of investigation is the social action as evidenced by the group. Social psychology is, on the other hand;
“the scientific investigation of how the thoughts, feelings and behaviours of individuals are influenced by the actual, imagined or implied presence of others” (George Allport, 1954, cited in Vaughan & Hogg, 2009, p. 2).
In this discipline, the research focusses on the individual as an actor who is influenced by the group. The types of research design typically differ between sociology and social psychology, the former relying on statistical models that assume populations and the latter on the physical science methods (and methodologies) of the experimental method. The type of evidence used by both differ significantly and as such the nature of values in research also may be diverse.
You are right that there are overlaps between disciplines, but the nature of territorialism in academia still leads scholars such as Thoits (1995) to argue that both sociology and psychology could benefit much from a more co-operative involvement.
Thoits, P. A. (1995). Social psychology: The interplay between sociology and psychology. Social Forces,73(4), 1231–1243.
Vaughan, G. M., & Hogg, M. A. (2009). Essentials of social psychology. Harlow: Prentice-Hall/ Pearson.
Weber, M. (1978). Weber: Selections in translation. (E. Matthews, Trans., W. G. Runciman, Ed.)Max Weber: Selections in translation. Cambridge: Cambridge University Press.