Jean-Baptiste Mouret wins award for his research into artificial life

19 September 2019

Jean-Baptiste Mouret, Research Director Inria in team Larsen common to Inria and Loria, has won the Award for Outstanding Paper of the Decade from the ISALsociety for The evolutionary origins of modularity, a paper published in March 2013, which he co-wrote with Jeff Clune, an associate professor at the University of Wyoming, and Hod Lipson, a professor at Columbia University, New York.

ISAL, the International Society for Artificial Life, aims to promote research and education on artificial life, which is a scientific endeavour to better understand life by attempting to replicate its mechanisms in a computer, a robot or even chemical substrates. Every year, this award is given to a paper written over the precious decade that had a significant impact in the field of artificial life.

From the evolution of biological networks to that of species

The winning paper attempts to better understand how biological networks evolve and, more broadly, how species adapt when their environment changes. Biological networks here mean protein interaction networks or gene regulator networks, i.e. an abstract representation of interactions between molecules in cells.

The networks that can be seen in nature are often highly modular, that is, they are made up of groups of entities whose subunits interact more with one another than with the subunits of other modules. This characteristic accelerates evolution, because being organised into small functional groups makes it easier to reorganise the network when the environment changes, unlike a non-modular network which is difficult to adapt without changing everything. It is a characteristic familiar to computer programmers, since designing software in the form of modules means that these can be reused for future software or for adapting it to new needs.

The question the paper asks is “How did modularity evolve in the first place?”. This is not straightforward because modularity provides a selective advantage in the long term (to adapt quickly), but not in the short term, since slightly more modular networks do not improve an individual’s chances of reproducing. Similarly, in engineering, the very concept of modularity is not necessarily obvious. For instance, IT teachers have often noted the need to explain to their students the utility of organising code into modules (or functions), whereas the students tend to write everything as one single function.

According to Jean-Baptiste and his colleagues, the selective pressure to reduce connection costs (connection length and number) at least partly explains why biological networks became modular. To explore this hypothesis, numerous simplified simulations of the evolutionary process were conducted. They showed that adding a direct selective pressure to reduce connection costs increased the modularity of the networks, a trait which then enables them to adapt in fewer generations when the environment changes. This pressure can also be combined with other effects like the pressure to adapt to cyclical environmental changes.

Three-time winner!

This is the third time for Jean-Baptiste, who has already won other awards from the learned society. In 2016 he won the ISAL Award for Outstanding Paper of 2015 (for another paper), and in 2017 the ISAL Award for Distinguished Young Investigator.

Although Jean-Baptiste is no longer working directly on this topic, this paper has been cited by many other papers, and its results have been widely discussed, presented and expanded upon in other papers on the evolution of modularity.