How a marble box taught epidemic theory
Engelmann shows that the 1920s Reed-Frost epidemic theory, taught with a trough and colored marbles, made epidemics into an academic research object without replacing fieldwork.
Source
A box, a trough and marbles: How the Reed-Frost epidemic theory shaped epidemiological reasoning in the 20th century
What they did
A historical reconstruction of the Reed-Frost epidemic theory at Johns Hopkins, reading its mathematical assumptions against earlier epidemic formalisms and against how Reed and Frost used a mechanical analogue of marbles in a trough to teach infectious-disease dynamics.
What they found
As epidemiology became an academic department, models supplied a general representation of interdependent contacts, susceptibility and immunity. Frost still insisted that a local measles outbreak could not be understood by abstraction alone. Models taught relations; they were not general laws of the 'epidemic streets'.
The limits
What it doesn't show
This is not a test of COVID models' accuracy, nor a new epidemic simulation. It does not claim that marbles caused later policy uses of modelling.
Key terms
- Reed-Frost epidemic theory
- 1920s Johns Hopkins formalisation of how the ratio of susceptible to immune people changes through an outbreak.
- Mechanical analogue
- Teaching model using an angled trough and colored marbles to visualise infectious-disease dynamics.
- Epidemiological reasoning
- Academic style that combines open-ended observation with mechanistic models of epidemics as research objects.
- Generative machines
- Models that do not only simulate outbreaks but help make epidemics into objects one can know and intervene in.
Flashcards
Research intelligence for this paper
See its role on concept claims, tensions it is part of, placement history, and related discoveries.
Quiz yourself
Reed-Frost was designed at?
Common questions
Who designed the Reed-Frost theory?
Biostatistician Lowell Reed and epidemiologist Wade Hampton Frost at Johns Hopkins in the 1920s.
What was the teaching device?
An angled trough and a box of colored marbles that visualised infectious-disease dynamics.
Did Frost think models explained a local outbreak?
No: the local configuration demanded observation; models were not general laws of a school measles outbreak.
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