To show how information builds up and flows among scientific disciplines, Columbia University computer scientist W. Bradford Paley, along with colleagues Kevin Boyack and Dick Klavans, categorized about 800,000 scholarly papers into 776 areas of scientific study (shown as colored circular nodes) based on how often the papers were cited together by other papers. Paley then grouped those nodes by color under 23 broader areas of scientific inquiry, from mental health to fluid mechanics.
1 Social Scientists Don’t Do Chemistry
The bigger a node is, the more papers it contains. Heavily cited papers appear in more than one node. Black lines connect any nodes that contain the same papers; the darker a link is, the more papers the connected nodes have in common. These links create the structure of the map and tend to pull similar scientific disciplines closer to one another.
2 Birds of a Feather
Paley refers to his map as a “feather boa”—the feathers being gently waving strings of key words that uniquely define each node’s particular subject matter. In tiny type, the word string “percutaneous tracheostomy, material review, autoimmune pancreatitis, and dialysis catheter,” for example, swirls off a node in the infectious disease area. Unlike the carefully calculated placement of the nodes, the team’s arrangement of the word strings on the page was left mostly to aesthetics.