At this point, it is instructive to compare the planetary science group and the molecular biology laboratory. The two groups clearly show distinct patterns in the division of labor among their members, a difference that is shaped by their research, the demands of experimental practice and also by the kind of expertise that different members bring to the group.
While the planetary science group is dominated by senior researchers who cooperate in an egalitarian way, the molecular biology laboratory features a distinct hierarchy between junior and senior scientists. While the planetary science group endorses a loose, rather exploratory and continuous mode of experimentation, the experiments carried out in the molecular biology laboratory are established procedures which serve a clear end. Therefore, planning and framing discussions, such as occurs in the planetary science group, are not necessary for the molecular biology laboratory, where the trajectory research activity is structured by generic experimental procedures—the purification and crystallization of proteins—in rather foreseeable ways.
While members of the molecular biology laboratory work on a series of resembling, yet distinct, research goals, members of the planetary science group pursue research goals that they, given their respective disciplinary backgrounds, differentially share. Since large parts of the research carried out in the planetary science group are perceived as a joint endeavor in which all involved scientists have their stake, the planetary science group displayed fewer instances of mutual support that might be described as genuine help.
What the differences between planetary science group and molecular biology laboratory show is that the division of labor can strengthen differentiation of expertise and professional individuation as well as it can, by creating learning opportunities, foster the convergence of expertise. In the planetary science group, the division of labor is organized so as to account for the resources that members bring to the group, that is, their expertise, their research interests, the infrastructure they have at their disposal, but also the time and the sheer labor they are able to put into a task. Members of the planetary science group specialize “horizontally," reflecting the differentiation between scientific disciplines and sub-disciplines. In contrast, members of the molecular biology laboratory often divide labor so as to account for the lack ofexpertise, that is, the need to learn and practice. Here, the division of labor is not only a measure of efficiency, but also a pedagogical means for helping all group members to acquire, roughly, the same kind of expertise—a pursuit of convergence that is, as we have seen, complemented by “vertical" specialization, which in different research tasks is in line with the hierarchy that distinguishes experienced senior scientists from less experienced junior scientists (cf. Laudel, 2001).
These differences in the division of labor between the planetary science group and the molecular biology laboratory carry over in reflections upon epistemic dependence and trust that I will unfold in the following Chaps. 7 and 8. As we will see, horizontal specialization entails different forms of dependence and requires different strategies to build up trust than a primarily vertical division of labor that seeks to create convergence in expertise.