When artists Jebney Lewis and K.R. Wood asked University of Pennsylvania mathematical biology postdoc Todd Parsons for a complex concept that needed to be communicated to the broader public, it was hysteresis: the idea that seemingly gradual change can suddenly become catastrophic.
Over dinner, pad of paper and pencils in hand, the three started brainstorming ways to visually embody the slow growth and sudden collapse. Several months and many sketches later, their work is now on display as an installation called Bifurcation, Hysteresis, Catastrophe, showing at Nexus Gallery in Philadelphia through April.
"A lot of people don't seem to be aware of how transition can be sudden and irreversible," says Parsons. Hysteresis is a concept that can apply to anything from ecology and the immune system to the global economy. It describes changes that elude our attempts to make simple linear predictions of future behavior. Hysteresis describes why collapsed fisheries don't recover when catch quotas are set to pre-collapse rates, and why the global economy hasn't recovered when failed banks were bailed out with fresh capital.
Lewis and Wood chose to illustrate hysteresis with the sudden shifts in transitional ecosystem mock-ups. Walking through a set of dark curtains, the viewer enters a dimly lit room where three sets of landscapes, constructed from wood and plastic, hang from the ceiling. The three -- a forest, a grassland, and a body of water -- demonstrate the dramatic shift in ecology that can occur in response to gradual changes in the environment. The suspended grassland and forest collapse into a desert landscape, while the water, as seen from below the surface, becomes choked with algae after eutrophication.
In keeping with spirit of their subject, the artists constructed the pieces from found materials: twigs, used plastic sheets sewn together, and chunks of wood from discarded pallets. To ground the art in the formulas that inspired it, Parsons sketched out statistical curves of ecological collapse in chalk on a gallery wall.
Hysteresis, explains Parsons, standing in front of his carefully transcribed equations "is Greek for something that lags behind." The amount of effort it takes to recover from catastrophic failure is far greater than the effort it would have taken to prevent catastrophe, he says. In other words, "The reverse point lags far behind the transition point," says Parsons, pointing to a line graph shaped like a curvy Z.
Lewis, Wood, and Parsons watch spectators milling through their exhibit on opening day. "It's surprising to me the number of people that have looked at the exhibit and thought that the math was made up," says Wood. "It really points to what a barrier most people feel to engaging in the world in that way," adds Lewis, "And maybe by extension, how they don't trust science."
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