Leveraging Complexity Science to understand Human Behavior

Part 1 | Sudden or discontinuous behavior change

By: Alok Gangaramany and Anushka Ashok

The 2021 Nobel prize for Physics has put the spotlight on Complexity Science as a key area of study for the future. With more than a decade of experience of working on wicked problems in the social sector, we have found the lens of Complexity Science being essential for our work. This pique in interest in the discipline, has also led us to examine and highlight the role of Complexity Science in understanding complex behavior problems. Complexity science provides a host of new tools and concepts to understand the systems we work in. At the same time, it raises some fundamental questions around the current approaches to behavior change. Through a series of posts, we aim to unpack how the lens of complexity science is shaping the way we look at problems, assumptions, and our processes.

This years Nobel Prize in Physics has brought into light the work of Complex System scientists for their contributions to the understanding of complex systems including the phenomenon of climate change. As mentioned by Bill Gates, the work has been critical in understanding the impact of global warming and potential pathways to sustainability.


The science of complexity has many applications. At Final Mile, we are particularly interested in leveraging this perspective in understanding human behavior and decision-making. People working in fields related to behavior change are well aware of the complexity and multi-dimensional nature of human decision-making. We rely on a number of tools that help us understand how individuals behave in different contexts, what might be the various mechanisms influencing them and how might we use this understanding to design behavior change interventions.

How does Complexity Science help us in this regard? It offers a whole host of new tools and concepts to achieve the same objectives outlined above and at the same time raises some fundamental questions around our current approach to behavior change. We plan to discuss these perspectives and their implications over a series of posts.

In this post, the first in the series, we will explore the general assumption that behavior change is typically slow and incremental in nature.

Conventional theories around behavior change indicate the path of behavior change as :

The framework is then applied to a specific behavioral context and moulded accordingly. The solutioning would typically entail helping an individual move forward in the journey by forming specific intentions, setting purposeful goals and addressing barriers to action. We might call this closing the Awareness / Intent → Action gap.

A Different Pathway for Behavior Change

  • What if behavior change follows a completely different pathway?
  • What if changes tend to be sudden and lacking intentionality?
  • What if it happens in the absence of a plan?
  • What if the outcome of goal directed behavior change is poorer than an event based behavior change?

The paper¹ “A chaotic view of behavior change: a quantum leap for health promotion” raises these fundamental questions and provides us with some direction. The authors share interesting examples about tobacco users trying to quit smoking or problem drinkers attempting to quit drinking. In the case of smokers, the attempt to quit smoking for about 50% or more was completely unplanned i.e. lacked any conscious cognitive appraisal. And from an outcome standpoint, the problem drinkers who quit due to a sudden transformational event were significantly more likely to be non-problem drinkers after a period of time, compared to those who had gone through an intentional behavior change process.

The above examples and approach does not necessarily mean that all behavior changes are sudden or discontinuous in nature. Perhaps, there is room for both gradual and discontinuous / sudden change? Or alternatively, some behaviors changes may be successful with one approach than the other. Another mechanism might be a combination approach i.e. the behavior change pathway could be a slow or gradual process followed by a sudden transformation. The possibilities are many and will likely vary for different contexts.

In our own work related to HIV prevention, we have also observed this trend especially when it comes to individual’s response to the risk of acquiring the disease. We noticed that the feeling of risk was not continuous. The fear of acquiring HIV would spike in some cases or events (e.g. learning that my partner has sexual relationships with someone who may be HIV positive) and may not exist at all during other times. The research pointed to the possibility of using these events as opportunities to offer support and resources that would facilitate adoption of safer behaviors. In the absence of such events, most prevention related communicated were considered irrelevant by the recipients.

Therefore the challenge for behavior change practitioners is to figure out:

a) What are the effective pathway(s) for behavior change problems that they are focused on? Are they planned or sudden or some combination of the two?

b) If behavior change is discontinuous, then how might we design interventions and support services that can sense the right opportunities to implement them?

c) What kind of methods should we use to accommodate non-linear patterns and capture disproportionate influences?

For the behavior change researchers, this perspectives suggests the need to reconsider the areas of enquiry, mechanism to collect data and process to analyze and synthesize research outputs. For example, what kind of research design is most suitable to capture key events? Given that significant number of events are random in nature, how might we build prediction models that can consider the randomness associated with behavior change? Are we in a position to even predict long-term behavior changes?

Overall, we think complexity science offers a dose of humility. Our current theories and approaches are likely to be inadequate to understand or explain behavior change especially the ones that are discontinuous in nature. Some behavior changes may be due to situations that are out of control for both the individuals and the intervention designers.

Accepting this situation does not mean that we need to give up on the practice of behavior change completely. It just means that we may need to reconsider our solutioning approach that could focus on sensing the readiness of individuals to change, rather than trying to build top-down nudge like solutions.


  1. Resnicow, K., & Vaughan, R. (2006). A chaotic view of behavior change: a quantum leap for health promotion. The international journal of behavioral nutrition and physical activity, 3, 25. https://doi.org/10.1186/1479-5868-3-25. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1586207/

Final Mile brings unique and proven capabilities in addressing complex behavioral challenges. As one of the first Behavioral Science & Design consultancies, Final Mile has had the opportunity to bring these to practice in a wide variety of sectors and contexts. We have executed highly complex behavior change projects across a wide variety of areas covering Global Health (HIV, TB, Maternal Health, WASH), Financial Inclusion, Safety across Africa, Asia, Europe, and the US.

Final Mile is also building a pandemic playbook that can be used as a potential toolkit by policymakers and implementors in mitigating Covid19 and future such pandemics.

Reach out to us at contact@thefinalmile.com.