Metaphors as Models of Mediation between Science and the Public:Newspaper Reporting of the 2001 foot and mouth disease outbreak

Brigitte NerlichInstitute for Science and Society

University of Nottinghambrigitte.nerlich@nottingham.ac.uk

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Overview

Some information about models, models in science, especially mathematical models and models in epidemiology

Case study of metaphors for models used by the media in 2001

Some conclusions And if there is time – some historical

background on models and metaphors

Models in science

„I never satisfy myself until I can make a mechanical model of a thing. If I can make a mechanical model, I can understand it. As long as I cannot make a mechanical model all the way through I cannot understand…” (Lord Kelvin).

“To speak of ‘ models’ in connection with a scientific theory already smacks of the metaphorical. Were we called upon to provide a perfectly clear and uncontroversial example of a model, in the literal sense of that word, none of us, I imagine, would think of offering Bohr’s model of the atom, or a Keynesian model of an economic system” (Max Black, 1962: 210).

Various types of models

Various types of models

Scale modelsAnalogue modelsMathematical modelsTheoretical models

Mathematical models According to Black: “the original field is thought

of as ‘projected’ upon the abstract domain of sets, functions, and the like that is the subject matter of the correlated mathematical theory” (1962, 223)

Differential Equation model of Predator-Prey System

Barbara Hepworth Stringed Figure (Curlew) (1956) - inspired by mathematical models

Models in epidemiology In 1766 Daniel Bernoulli studied smallpox

morbidity and mortality data to demonstrate the efficacy of vaccination - first use of mathematical modelling to study infectious diseases

Some roles of modelling in epidemiology are: To demonstrate general laws governing the

dynamics of epidemics To estimate values of parameters that cannot be

directly measured To analyse the spread of an epidemic and control

measures

Models, metaphors and the media

This paper investigates how metaphors were used by the media to conceptualise epidemiological modelling during the 2001 foot and mouth crisis.

Models may be seen as scientists’ metaphors and metaphors may be seen as lay people’s mental modelling devices.

Quantitative epidemiological modelling - 2001

In 2001 quantitative epidemiological models were used strategically, tactically and operationally in decision-making, management and intervention

As the virus spread faster and in more unexpected ways than during previous outbreaks, epidemiological modellers were called upon not only to monitor the spread but also to assist in real-time disease-control management and to help choose between policy options

contiguous cull or 24/48 hour policy

Timeline of events

14/03/01 MAFF provided Imperial College with data on the disease between report to confirmation, and confirmation to slaughter.

16/03/01 MAFF suspected that the epidemic was out of control - meeting between MAFF, the FSA, epidemiologists, the Chief Vet Jim Scudamore, and the government’s Chief Scientific Advisor Sir David King

26/03/01 introduction of ‘contiguous cull policy’ based on Imperial team’s modelling exercise

29/03/01 cull began

Modelling teamsFour modelling teams and three types of models

A team from Imperial under Professors Anderson, Ferguson and Donnelly used a deterministic model (a mass action model using moment closure to approximate neighbourhood effects)

Two teams from Cambridge and Edinburgh under Professors Grenfell from Cambridge and Woolhouse from Edinburgh used a non-deterministic model (a spatially explicit Monte Carlo simulation model)

This was also the case for the MAFF/Veterinary Laboratories Agency (VLA) team under Professor Wilesmith (a spatially explicit microsimulation model – Interpread)

DIY modelling (Royal Society)

Data set

The Lexis Nexis database was used to search all UK newspapers between February and July 2001 using the key words ‘foot and mouth’ and ‘modelling’

Out of 33 articles found, 18 contained longer discussions of the modelling exercise.

Modellers are detectives

mid-February 2001 Epidemiologists, especially Paul Kitching, are

framed as detectives “on the trail of the latest killer virus”

Well-established metaphor ‘detective work’ has long been a metaphor for

clinical acumen and epidemiologists in particular are often

referred to as ‘disease detectives’

Modellers are soldiers and Models are Weapons Late Feb. 2001: modellers become soldiers in the fight against

the epidemic issue of ‘tracing’ or ‘mapping’ the virus back

to its hiding place is replaced by the issue of ‘controlling’ the spread of the virus

this metaphor imposes a new similarity relation between modellers and their work

it indicates a shift from the use of ‘tracking’ models to the use of ‘tactical’ models

Models become weapons

Modellers are soldiers

“Has the A-team defeated the virus? The fight against foot and mouth has been spearheaded by a task force of epidemiologists – their weapon is clever software”

“a struggle against the odds” (Highfield, Daily Telegraph, 12/04/01)

Models are ‘workaday’ tools

The foot and mouth crisis marks perhaps the first serious test in medicine of computer predictions, a workaday tool in other fields, said Prof Anderson ... "Medicine very rarely uses these sophisticated computational and mathematical methods that are used routinely in engineering and physics," he said. (Highfield, ibid.)

maps image of engineer designing aeroplanes onto engineers ‘designing’ the course of an epidemic - stresses control

Modellers are magicians and models are crystal balls

“software wizards and mathematicians who can set up and run computer models that can predict the impact of MMR scares, novel Aids treatments or cattle culls”

“computerised crystal-ball gazing to predict the spread of disease”

From descriptive to prescriptive modelling

Models are the disease

“the epidemic peaking within the next seven days, Professor King said”

“with new cases following a diminishing curve that is set almost to peter out by the time of an expected June election”

“Nobody is saying that this epidemic can just be switched off. […]."

“that the epidemic was ‘flattening out’”

(Connor, Independent, 5/04/01)

Policies based on models are outdated weapons

The blanket ring culls used for much of the epidemic were "a blunderbuss approach", said Dr Alex Donaldson, of Pirbright, who gave the Government his preliminary findings on April 19. (Highfield, ibid.)

But he [Scudamore] was overlooked and a scatter-gun approach was taken, slaughtering all animals within 48 hours of confirmation of each new case. (The Western Morning News, 27/04/01)

Models are lies

“some very seductive graphs”

“DAMNED LIES AND STATISTICS”

(Booker, Sunday Telegraph, 29/04/01)

Conclusion

Shifts in metaphors: From modellers as detectives to modellers as

solders to modellers as magicians to modellers as liars

From models as wonder-weapons or workaday tools to models as lies

The shift in metaphors indicates a shift from seeing models as a legitimate ‘objective’ basis used by decision makers to pursue science-based policies towards seeing them as tools used to legitimise increasingly difficult political decisions.

Conclusion

Models and metaphors highlight and hide, simplify and abstract.

When articles compare models to crystal-ball gazing or reduce the use of statistics to lies, they highlight some aspects of the modelling exercise but hide its complexity.

Just as modellers may be seduced by the models they create, so journalists may be seduced by the metaphorical models they use.

They are shortcuts through complex scientific debates and provide readers with ‘models’ that might be clearer and more real than the reality they describe.

Models and metaphors - or understanding one thing in terms of another

Vaihinger, Harré, Hesse, Black, Ricoeur Heuristic fictions Representation, simulation, selectivity,

simplification Mapping from known to unknown Mapping from source to target Although there exists a bewildering array of

definitions of what a model is -- what Wartofsky called the “model muddle”-- there seems “to be general agreement that modelling involves the relationship of representation or correspondence between a (real) target system and something else” (Webb, 2001)

Models and metaphors as heuristic fictions

both models and metaphors involve mapping a real-world phenomenon onto a “heuristic fiction”;

both involve talking in a different way about that phenomenon;

both involve introducing a new “language or dialect” into the study of the phenomenon (see Black, 1962: 229)

both allow us to “see a new subject matter in a new way” and to “see new connections” (ibid., p. 236 and 237)

Models as metaphors

Metaphors as models

1860s - William Whewell conceptualised economic trade in terms of tides and created new model of economy

1860s - metaphor of ‘organism’ informs thinking about language

1960s - metaphor of a ‘language’ inspires biology

And so on