Behavior Follows the Path of Least Resistance

I was sitting in Dar es Salaam examining a map of Tanzania to determine what pathways heroin would likely travel through the country. This was important to mobilize treatment sooner rather than later. I looked at the map and traced the main roads. I concluded that drugs would travel up from Dar es Salaam to Arusha, then north to Nairobi or west to Mwanza. There was doubt in the room – probably because I spoke with certainty. Did I have some inside information? Not at all. Was I just an overly confident foreigner who spoke too much and listened too little? Hopefully not. I pointed out that drug trafficking will follow the path of least resistance. Moving product over large main roads to markets for distribution (meaning cities with places to ship drugs to foreign markets) was simply easy and “good business.”

The initial focus of treatment for opioid use disorder (the proper name for heroin addiction) was Dar es Salaam. This was a logical choice since drugs were arriving along the coast. The question remained if the drugs would move inland. And why would they? Wasn’t the goal to move drugs to Europe (markets with a higher ROI for the drugs)? And wasn’t the largest airport in Dar es Salaam? Yes, but drug trafficking requires movement of product to and through multiple locations to try to make sure that something makes it to the final destination. If you put everything on one container and that boat gets stopped, you are in real trouble. So, you move stuff to multiple places and always follow the path of least resistance. So, drugs move up from Dar es Salaam to Arusha (international airport), or north to Nairobi (another airport), or west to Mwanza (access to Lake Victoria). To demonstrate this, Annabel Tan, a former student and all-star, spent the summer in Mwanza – the farthest large town northwest of Dar es Salaam. That summer she located hundreds of fishermen who were using heroin (her paper is available for free at?PlosOne). It was clear that these fishermen, who were not fishing as much because of international fishing on Lake Victoria, needed income. Drug trafficking seemed like a tempting occupation for them. It was logical to predict that heroin would move across Lake Victoria to the western shores of Kenya and up to Kampala, Uganda following their traditional fishing routes. It was reasonable to predict that in the wake of heroin, addiction treatment would be needed in Kisumu, Kenya which sits on Lake Victoria. And that is what happened.

When a team proposes a solution, I begin to look at the path of least resistance that people will take when implementing the plan (or their interpretation of the plan). Policy makers are sometimes perplexed that a policy they create does not always have the intended consequence in regulating behavior.?This may be simply because their policy was solving the wrong problem (see?Asking the Right Question), but sometimes it is a failure to monitor for unintended consequences which follow the path of least resistance.

The point of these illustrations is that some human behavior is predictable if you know the path of least resistance someone will take to achieve their desired outcome. And if you find that pathway, you will have insight into likely future outcomes. Critically, cognitive biases often follow the path of least resistance as they seek to resolve cognitive dissonance with either rationalization or confirmation bias (see good choice architecture for more background and cognitive dissonance for greater detail). Understanding these systems has real material benefits. Looking at the map, thinking about behavior, and having an adventurous student willing to overcome obstacles to trek to Mwanza meant that, ultimately, lives were saved because her data motivated the government to sponsor the first treatment program in Mwanza. Understanding the path of least resistance and human behavior is critical in all program planning. Problems may be complex, but if the solution is overly complex for a person to navigate, it stands to reason that no one will use it.

When you are wondering what will happen when you roll out a plan, ask yourself, “What is the path of least resistance? What will most people do most of the time?" Not what do you want them to do, but what are they really going to do? Drugs, diets, exercise (or lack thereof), medication adherence, etc. all follow the path of least resistance. This is the reason HIV medications went from multiple pills a day to one pill once a day to injectables. Isn’t an injection several times a year easier than multiple pills several times a day? Creating solutions that capitalize on the natural human tendency to follow the path of least resistance will provide lasting change because such solutions require minimal effort to be maximally successful.