The quality of a tie may not only be defined by the content of interactions with a type of association. It can also be defined by its form or strength. Strong ties are generally considered to be influential ties. They're your close friends. And, for example, when close friends pressure you, it has greater influence on you than when, say, a total stranger or an acquaintance pressures you. Strong ties entail frequent interaction. They entail positive liking or affect, and it's typically mutual. And they have a history to them. And in network research we characterise strong ties as having bonding capital or a cohesive pull on people that guides their action. And we were frequently referred to these relations as ones of friendship, mutual support, liking, love, enemies and things like that in the opposite direction. In contrast week ties are more infrequent their casual interactions between acquaintances where a strong ties have bonding capital and bring local persons into greater contact. Week ties have bridging capital and they typically bring distant persons into contact across groups. So, in certain regards, these two types of association reflect the ties that we saw in the community of practice, the strong ties for that, and within a network of practice. Those are the weak bridges across groups. And we saw those in organizational learning theories. So, in some ways this kind of depiction, this distinction is somewhat consistent with that theory that we had in week five of the course. Social network research has identified a consistent set of mechanisms that form interpersonal relations in firms and other settings. Most of these findings concern strong ties, but they afford analysts and managers some sense for how tie creation could be facilitated. So that's why I want to take some time to related those theories or those mechanisms here. The first mechanism concerns how people naturally form close ties when they're in the same proximity of one another. So here, proximity breeds ties. We often a lot of our relationships are a matter of convenience. And contact, the opportunity for contact is key to developing a friendship. Now, another theory concerns how similar two persons are. And here what we call homofily happens. Or what the saying says is when birds of a feather flock together. We seek out people like ourselves. And that builds certainty and knowledge about one another. Another source of ties comes from exchange or rational choices concerning them. So we look for something in the other and they look for something in us and we exchange that and forming kind of a relationship. Another kind of mechanism driving relation formation is the normal reciprocity. A long time ago anthropologists found that gift giving induces a sense of obligated reciprocation across individuals and this holds across societies, so for a lot of you out there this is a great excuse for a reason for why you should be the one to buy the first drink when you meet everyone else. Next, is a theory about control, other theories like that a status attainment and control or dominance suggest that people seek out interpersonal advantages and control. So, this kind of tendency you see with all kinds of primates and the like where they form rank order hierarchies. And then we have a theory of balance where people see consistency in their relationships more generally. For example, most of us feel at unease when our friends befriend our enemy. We have to either sever our tie from friend, or our friend has to make my enemy their enemy, and if they do that we can stay friends. So there's this kind of transitivity or balance that we have in relationships that extend beyond the dyad to the triad. Last, an underemphasized mechanism of tie formation concerns practices and identities. In most organizational context we queue routines and they oblige us to assume different interaction roles, like one of listener, hearer Inquisitor, speaker, coauthor, and so on. The same goes for cued identities. We frequently cue notions of a story tie and what that entails. So for example, when I make gestures of friendship, I assume that entails reciprocation, frequent contact, supportive interactions, and so on. When I evoke the identity of professor, that cues other expected role relations and their interactions. So all of these micro-mechanisms have been studied and related to tie formation, and they suggest pathways by which we can create networks within organizations. So we have multiple types of networks and a variety of mechanisms have been found to kind of generate these networks. Now what about positioning within them though? Social network scholars love to study the positioning of actors and networks and they love to do this, because it's not just the overall form of a network that defines action potentials It's also your location within them that does. Now, the two kind of combine in interesting ways. After all, it's a very different situation to be a central actor in a centralized network than it is to be a central actor in a fractured one. Nevertheless, being a central actor in any kind of network should have certain advantages. So when a network analyst speaks of positions, they're really referring to the notion of centrality. And centrality can refer to positions of both prominence or to positions of both mediation and brokerage. There's of course other notions of central positioning that we talk about in social network analysis, but I'm going to limit it to these two for the purposes of this course. And the network here that you see in the figure, you can see the prominent persons and the peripheral ones readily. I mean it's not too hard, you look for the ones with the most highs as prominent, and the ones with the least as being peripheral. But then there's these individuals who are on the path of others and if we took them out of the network it would fall apart. These are key mediators between different parts of the organizational structure. And identifying these central players can be useful to a firm, and especially when it comes to understanding information flows, and bottlenecks in the transfer of firm resources. Another type of network position or location is more group based, and it concerns the location of a hub of interconnectivity. When looking at networks analysts frequently try to identify these sets of factors in clusters of ties, since they reflect locations within the network where conformity and social influence likely arises. There are also spaces of redundant information, so clusters and groups of interconnected actors are important to the study of firm social structures, because they often influence firm outputs and behaviours. I'll show you more of this in the next lecture when I talk about how groups or cliques of interconnected actors. Greatly shape the behaviours that they exhibit within the work setting. To this point, we've describe organizations as webs of transactions. And actors as occupying different positions. Or groups within those networks. This can be complicated further if we consider that social realities are such, that organizational actors are actually embedded in multiple networks. This is where things get both more interesting and more complex. So, let's take the example of something, some of you may be familiar with which are trade associations, in most fields of business trade associations assume a position central to information exchange, but they're peripheral to the networks exchanging financial resources, because of this, they can persuade other organizations within their field by the use of information as a resource. But they can't really enforce other firms to conform to their demands because they lack hard financial resources. Within firms it's a similar situation where there can be multiple types of relationships and actors can assume different positions across them. So, let's look at a faculty in a west coast research university from 1993 to 2000. The school has around 1500 faculty. That range in status from some being clinical faculty. Engaged in the hospital and patient care. To others being assistant professors that aren't tenured yet. To those that are fully tenured. Okay? So, in addition, these faculty come from different divisions of the university. Some come from the humanities. Others from the social sciences the orange. Some from law and education which I believe is white. And others are from the natural sciences which I'm going to make dark green and earth sciences which is the light green here. And then finally the physical sciences and engineering and medicine. So, we have all this divisions and with any university there's multiple types of association that can arise whether, it's through the training of students and advising of doctoral students. Whether it's to the collaboration on grants whether it's through collaborations on publications, and so on. There's a variety of these different kinds of association and different divisions of university assume different positions in those networks. So let's impose the network of collaborations on these actors. In particular, let's look at where coauthoring of publications happens. They happen mostly in medicine, as well as the hard sciences and engineering. Notably, those two fields collaborate more within them, themselves, and then between them. And there's a good deal of crossover, but still you see more clustering within. By contrast, social sciences and humanists. Mostly publish alone, at least within this period of 1993 to 2000. Now let's look at grant collaborations. Notice how the network shifts and we get a second hub of dense collaboration within engineering. But again, there's a clear clustering within medicine and engineering. And a little bit of inter-field collaboration across engineering and medicine. However the hard sciences or physical sciences are mostly kind of collaborating with engineering at this point. Now let's look at student training, and how faculty work together to provide that. Here we see faculty who are linked when the co advise doctoral students. Notice how the network disappears over medicine, and it forms over the social sciences and humanities. And notice how the collaborating medical faculty are mostly tenured, they're not clinical line. So the clinical line are the circles, the tenured faculty are the pink triangles. So what do we learn from all this? We learn that each field is embedded in multiple types of activities and networks of collaboration, but they assume different positions across. And this likely results in greater cumulative advantages to each field. So, on the one hand, we have the medical faculty which collaborate on mostly publications and grants but not necessarily on the training of doctoral students. It's more through medical students which aren't represented in these images. The social science and humanities faculty collaborate over student training of doctoral students. The also publish and write an occasional grant, but it's not a point of collaboration. They solo author a lot of that. Last, engineers and scientists collaborate in everything they do. Moreover, they frequently interact with medicine. So, from this, we see a differentiated collaboration structure in the university. The implication is that the social sciences and humanities mostly transfer knowledge by the mutual efforts of training students. In contrast to medicine transfers knowledge mostly over the conducting of research or team science. And it probably has a lot of contact with post stocks as opposed to pre-doc students. And yet other fields are high speed thorough fairs for knowledge by collaboration and everything they do. So, engineering and the hard sciences are very much a lynch pin in this university, bringing together high powered domains of research, training and publication.