A bridge is a type of social tie that connects two different groups in a
social network
A social network is a social structure made up of a set of social actors (such as individuals or organizations), sets of dyadic ties, and other social interactions between actors. The social network perspective provides a set of methods fo ...
.
General bridge
In general, a bridge is a direct tie between nodes that would otherwise be in disconnected components of the graph.
This means that say that A and B make up a social networking graph,
is in A,
is in B, and there is a social tie
between
and
. If
were to be removed, A and B would become disconnected components of the graph. This means that
is a bridge.
For example, A could represent a corporation and B Congress.
could then be a lobbyist and
a Congressman.
would then represent the relationship between that corporation and Congress that only exists through the lobbyist.
This is very similar to the concept of a
bridge
A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually someth ...
in graph theory, but with special social networking properties such as strong and
weak ties.
Local bridge
Local bridges are ties between two nodes in a
social graph that are the shortest route by which information might travel from those connected to one to those connected to the other. Local bridges differ from regular bridges in that the end points of the local bridge once the bridge has been deleted cannot have a tie directly between them and should not share any common neighbors. Also if the local bridge is deleted the distance between these two nodes will be increased to a value strictly more than two.
Social network implications
In
social network
A social network is a social structure made up of a set of social actors (such as individuals or organizations), sets of dyadic ties, and other social interactions between actors. The social network perspective provides a set of methods fo ...
s, bridge relationships transmit information from one group to another. The breadth of information spread depends heavily on the number and connectedness of the bridges available to the originators of the information. Author
Malcolm Gladwell
Malcolm Timothy Gladwell (born 3 September 1963) is an English-born Canadian journalist, author, and public speaker. He has been a staff writer for ''The New Yorker'' since 1996. He has published seven books: '' The Tipping Point: How Little ...
characterizes people that habitually act as bridges as
Connectors in his book ''
The Tipping Point
''The Tipping Point: How Little Things Can Make a Big Difference'' is the debut book by Malcolm Gladwell, first published by Little, Brown in 2000. Gladwell defines a tipping point as "the moment of critical mass, the threshold, the boiling po ...
''.
Bridges and local bridges are powerful ways to convey awareness of new things, but they are weak at transmitting behaviors that are in some way risky or costly to adopt. Weak ties are able to spread awareness of a joke or an on-line video with remarkable speed, but political mobilization moves more sluggishly, needing to gain momentum within neighborhoods and small communities. McAdams observed that strong ties, rather than weak ties, played a much more dominant role in recruitment to Freedom Summer on college campuses in the 1960s.
[Ahn, Luis von. "Thresholds and Collective Action." Sept. 16, 2008. Slides 9-10. http://scienceoftheweb.org/15-396/lectures/lecture07.pdf ]
See also
*
Interpersonal ties
In social network analysis and mathematical sociology, interpersonal ties are defined as information-carrying connections between people. Interpersonal ties, generally, come in three varieties: ''strong'', ''weak'' or ''absent''. Weak social t ...
References
{{Social networking
Social networks