I attended a talk recently given by Dr Sara Savage from Cambridge University entitled “Bad Religion: when is faith healthy or unhealthy?”. The title was a bit of a misnomer, as there was little discussion of religion per se, but there was a greater deal of fascinating psychological research on the drivers of extremist ideology. Dr Savage outlined the theory of “integrative complexity“, developed by Peter Suedfeld over the past 30 years. Integrative complexity is a method of metacognitive reasoning (i.e. being aware of how and what you are thinking, and why) that incorporates empathic and diverse approaches towards the views of others in an attempt to construct a coherent and objective view of a given situation. The argument has been made that extremist ideologies (whether these are religious, political or social) tend to stem from a narrowing of perspectives (a drop in integrative complexity, or “IC”), and that conflict resolution is best achieved by those who “see complexity”. Indeed, Suedfeld and colleagues have published analyses of IC within the context of the Cuban missile crisis and surprise attacks.

It struck me that what Dr Savage covered during her talk had direct parallels with the ecological debate over diversity and stability. When there are a greater number of species within a community, that community is thought to be (although these relationships are far from settled) more robust to perturbations, in particular through resilience against invasive species and disease. This can be due to the presence of redundant species (multiple species perform the same role and so the loss of one species is mitigated by its immediate replacement by another), complete use of resources (a “full” community leaves no space for new arrivals), and reduced abundance of particular species (which reduces the chance of spread of disease in any particular species). This perspective was very common through to the 1970s, but the advent of null models and complexity analysis (particularly through the work of Bob May) suggested that the opposite may be true: that complexity is negatively related to stability. Subsequent work has focused not on the number of species within the ecosystem but on the relationships between those species, and it has come to be recognised that it is the strength of interactions between species that governs the resilience of those systems. Hence an appreciation of the structure and function of ecological networks has largely replaced the broader measures of diversity that were used in the early stages of the debate.

Returning to IC, the measurement of IC depends on two complementary concepts: (i) differentiation, which involves the delineation of different perspectives or viewpoints, and (ii) integration, which involves the connection of those differentiated viewpoints into a coherent network. It seems that this pattern of development within the concept of IC mirrors that of the development of “complexity” within the ecological literature. This makes me wonder whether the two fields could learn something from one another:

• Network theory has been applied robustly to ecological systems, with the integration of not only the relationships between species but also the strength and directionality of those relationships. Has IC reached this level of complexity in the description of integration?
• There are empirical descriptions of the effect of IC on conflict resolution, and on the alleviation of extremist ideologies within individual subjects. Are there analogies in the design of these studies that can be applied within the ecological sphere to better understand ecosystem development?

It is always fascinating when fields cross-over!