Thinking in Systems: A Primer

by Donella H. Meadows

So instead of finding a long-term optimum, we discover within our limited purview a choice we can live with for now, and we stick to it, changing our behavior only when forced to.

We live in an exaggerated present—we pay too much attention to recent experience and too little attention to the past, focusing on current events rather than long-term behavior. We discount the future at rates that make no economic or ecological sense.

We don’t let in at all news we don’t like, or information that doesn’t fit our mental models. Which is to say, we don’t even make decisions that optimize our own individual good, much less the good of the system as a whole.

Taking out one individual from a position of bounded rationality and putting in another person is not likely to make much difference. Blaming the individual rarely helps create a more desirable outcome.

From a wider perspective, information flows, goals, incentives, and disincentives can be restructured so that separate, bounded, rational actions do add up to results that everyone desires.

To paraphrase a common prayer: God grant us the serenity to exercise our bounded rationality freely in the systems that are structured appropriately, the courage to restructure the systems that aren’t, and the wisdom to know the difference!

Being less surprised by complex systems is mainly a matter of learning to expect, appreciate, and use the world’s complexity.

Understanding archetypal problem-generating structures is not enough. Putting up with them is impossible. They need to be changed. The destruction they cause is often blamed on particular actors or events, although it is actually a consequence of system structure.

That is why I call these archetypes “traps.”

Policy resistance comes from the bounded rationalities of the actors in a system, each with his or her (or “its” in the case of an institution) own goals. Each actor monitors the state of the system with regard to some important variable—income or prices or housing or drugs or investment—and compares that state with his, her, or its goal. If there is a discrepancy, each actor does something to correct the situation.

In a policy-resistant system with actors pulling in different directions, everyone has to put great effort into keeping the system where no one wants it to be.

Intensification of anyone’s effort leads to intensification of everyone else’s. It’s hard to reduce the intensification. It takes a lot of mutual trust to say, OK, why don’t we all just back off for a while?

One way to deal with policy resistance is to try to overpower it. If you wield enough power and can keep wielding it, the power approach can work, at the cost of monumental resentment and the possibility of explosive consequences if the power is ever let up.

The alternative to overpowering policy resistance is so counterintuitive that it’s usually unthinkable. Let go. Give up ineffective policies. Let the resources and energy spent on both enforcing and resisting be used for more constructive purposes.

The most effective way of dealing with policy resistance is to find a way of aligning the various goals of the subsystems, usually by providing an overarching goal that allows all actors to break out of their bounded rationality.

The most familiar examples of this harmonization of goals are mobilizations of economies during wartime, or recovery after war or natural disaster.

The trap called the tragedy of the commons comes about when there is escalation, or just simple growth, in a commonly shared, erodable environment.

In any commons system there is, first of all, a resource that is commonly shared (the pasture). For the system to be subject to tragedy, the resource must be not only limited, but erodable when overused.

A commons system also needs users of the resource (the cows and their owners), which have good reason to increase, and which increase at a rate that is not influenced by the condition of the commons.

The tragedy of the commons arises from missing (or too long delayed) feedback from the resource to the growth of the users of that resource.

Tragedy can lurk not only in the use of common resources, but also in the use of common sinks, shared places where pollution can be dumped.

There are three ways to avoid the tragedy of the commons. Educate and exhort. Help people to see the consequences of unrestrained use of the commons. Appeal to their morality. Persuade them to be temperate. Threaten transgressors with social disapproval or eternal hellfire.

Privatize the commons. Divide it up, so that each person reaps the consequences of his or her own actions. If some people lack the self-control to stay below the carrying capacity of their own private resource, those people will harm only themselves and not others.

Regulate the commons. Garrett Hardin calls this option, bluntly, “mutual coercion, mutually agreed upon.” Regulation can take many forms, from outright bans on certain behaviors to quotas, permits, taxes, incentives. To be effe...

You may not broadcast at will over the wavelengths that carry radio or television signals. You must obtain a permit from a regulatory agency. If your freedom to broadcast were not limited, the airwaves would be a chaos of overlapping signals.

Some systems not only resist policy and stay in a normal bad state, they keep getting worse. One name for this archetype is “drift to low performance.”

Standards aren’t absolute. When perceived performance slips, the goal is allowed to slip.

The lower the perceived system state, the lower the desired state. The lower the desired state, the less discrepancy, and the less corrective action is taken. The less corrective action, the lower the system state.

Drift to low performance is a gradual process. If the system state plunged quickly, there would be an agitated corrective process. But if it drifts down slowly enough to erase the memory of (or belief in) how much better things used to be, everyone is lulled into lower and lower expectations, lower effort, lower performance.

There are two antidotes to eroding goals. One is to keep standards absolute, regardless of performance. Another is to make goals sensitive to the best performances of the past, instead of the worst.

“I’ll raise you one” is the decision rule that leads to escalation. Escalation comes from a reinforcing loop set up by competing actors trying to get ahead of each other.

The most common and awful examples are arms races and those places on earth where implacable enemies live constantly on the edge of self-reinforcing violence.

Negative campaigning is another perverse example of escalation. One candidate smears another, so the other smears back, and so forth, until the voters have no idea that their candidates have any positive features, and the whole democratic process is demeaned.

Advertising companies escalate their bids for the attention of the consumer. One company does something bright and loud and arresting. Its competitor does something louder, bigger, brasher. The first company outdoes that.

Escalation in morality can lead to holier-than-thou sanctimoniousness. Escalation in art can lead from baroque to rococo to kitsch. Escalation in environmentally responsible lifestyles can lead to rigid and unnecessary puritanism.

One way out of the escalation trap is unilateral disarmament—deliberately reducing your own system state to induce reductions in your competitor’s state.

The only other graceful way out of the escalation system is to negotiate a disarmament. That’s a structural change, an exercise in system design.

Using accumulated wealth, privilege, special access, or inside information to create more wealth, privilege, access or information are examples of the archetype called “success to the successful.” This system trap is found whenever the winners of a competition receive, as part of the reward, the means to compete even more effectively in the future.

Success to the successful is a well-known concept in the field of ecology, where it is called “the competitive exclusion principle.” This principle says that two different species cannot live in exactly the same ecological niche, competing for exactly the same resources.

Another expression of this trap was part of the critique of capitalism by Karl Marx. Two firms competing in the same market will exhibit the same behavior as two species competing in a niche.

The trap of success to the successful does its greatest damage in the many ways it works to make the rich richer and the poor poorer.

Species and companies sometimes escape competitive exclusion by diversifying. A species can learn or evolve to exploit new resources. A company can create a new product or service that does not directly compete with existing ones.

The success-to-the-successful loop can be kept under control by putting into place feedback loops that keep any competitor from taking over entirely. That’s what antitrust laws do in theory and sometimes in practice.

The most obvious way out of the success-to-the-successful archetype is by periodically “leveling the playing field.” Traditional societies and game designers instinctively design into their systems some way of equalizing advantages, so the game stays fair and interesting.

These equalizing mechanisms may derive from simple morality, or they may come from the practical understanding that losers, if they are unable to get out of the game of success to the successful, and if they have no hope of winning, could get frustrated enough to destroy the playing field.

This trap is known by many names: addiction, dependence, shifting the burden to the intervenor. The structure includes a stock with in-flows and out-flows.

The stock is maintained by an actor adjusting a balancing feedback loop—either altering the in-flows or out-flows. The actor has a goal and compares it with a perception of the actual state of the stock to determine what action to take.

The drugs do nothing to improve your real situation—in fact, they likely make it worse. But the drugs quickly alter your perception of your state, numbing your senses and making you feel tireless and brave.

The trouble is that the states created by interventions don’t last. The intoxication wears off. The subsidy is spent. The fertilizer is consumed or washed away.

Shifting a burden to an intervenor can be a good thing. It often is done purposefully, and the result can be an increased ability to keep the system in a desirable state.