Sheffer’s The Evolutionary Basis of Rigidity

Scheffer, M., and F. R. Westley, The Evolutionary Basis of Rigidity: Locks in Cells, Minds, and Society Ecology and Society 12(2): 36, 2007.


Feedbacks leading to alternative stable modes of behavior occur on levels varying from the cell and the mind to societies. The tendency to lock into a certain pattern comes at the cost of the ability to adjust to new situations. The resulting rigidity limits the ability of persons, groups, and companies to respond to new problems, and some even suggest that it may have contributed to the collapse of ancient societies. In the face of these negative effects, it may seem surprising that lock-in situations are so ubiquitous. Here, we show that the tendency to lock into one of several alternative modes usually serves an apparent purpose. In cells, it filters out noise, and allows a well-defined and consistent behavior once a certain threshold is passed. Basically, the same holds for the attitudes and behavior of individuals and groups. This functionality is not surprising as it has evolved through selection for fitness. Understanding why rigidity makes sense may help in finding ways to avoid traps in situations where flexible response and innovation are needed.


Although systems may respond to changes in their environment smoothly, they are often rather insensitive over certain ranges of the external conditions, although responding relatively strongly around some threshold condition. … A crucially different situation arises when … the system has two alternative equilibria, separated by an unstable equilibrium … that marks the border between the basins of attraction of the alternative stable states.

… Note that, if one monitors the system on a stable branch before a switch, little change in its state is observed. Indeed, such catastrophic shifts occur typically quite unannounced, and “early warning signals” of approaching catastrophic change are difficult to obtain. … [A] pattern, in which the forward and backward switches occur at different critical conditions (Fig. 2 a), is known as hysteresis.

Everyday examples of systems with such properties are well known. For instance, the slowly increasing pressure of a finger may eventually flip a switch and abruptly turn on a light. Hysteresis occurs, because reducing the pressure to levels occurring before the switch was flipped will not switch the light off again. … [The] idea is less self-evident with respect to complex systems such as cells, ecosystems, the climate system, and societies.

[We] wish to address the question why “locks” seem so common, even if the associated rigidity that comes with them appears to be a negative thing. We will argue that, especially at physiological levels, such locks usually have an obvious evolutionary advantage, and that this may be true for group behavior too, even though locked attitudes and modes of behavior in individuals and groups can easily lead to undesirable lock-in situations. Rather than using the dynamic systems terminology for alternative attractors, we will use the intuitive term “lock” to refer to a mode that the system does not easily get out of again due to self-stabilizing feedback. We use the term “trap” for a lock with a negative connotation.


On a cellular level, alternative attractors are a common phenomenon. They usually serve a clear purpose. For instance, it is important for cells to “decide” between distinct options over their life cycle.

[Such] bistability in cell signaling pathways serves to filter out noise (irrelevant random fluctuations in the environment) and yet allows the cell to respond decisively if stimuli exceed a certain threshold.


Human minds are also notorious for locking into one of several contrasting states.

On a more subtle level, the mind has a tendency to lock into one of several alternative interpretations of reality. … It appears to be difficult to see different interpretations simultaneously, and the resulting “snapping” to one of several alternative interpretations seems to happen on different levels, ranging from interpretation of pictures to more complex theories and world views. Scientists are often faced with this problem in their work as there is “the imminent danger of an unconscious selection and of a magnifying of phenomena that fall into harmony with the theory and support it and an unconscious neglect of phenomena that fail of coincidence”. The same mechanism may play a role in ideology of all kinds, from political to religious beliefs.

One can imagine that the tendency to quickly fit complex observations to search images serves a purpose.

Also, behavioral patterns have the tendency to lock into a particular mode, from which it may be difficult to break free. Again, this may often serve a purpose.

Perhaps the benefits of consistency also explain the curious phenomenon known as the “sunk-cost effect.” Economic theory tells us that prior investment should not influence one’s consideration of current options. Only the incremental costs and benefits of the current options should influence the decision. However, there are numerous examples suggesting that humans deviate from that rational path and can be trapped into a positive feedback loop between prior investment and behavioral choice. … Whatever the explanation is, adult humans apparently have a tendency to stick to a certain mode of behavior even if it is rationally a bad choice. This lock-in mechanism, caused by apparent self-reinforcing adherence to a mode of behavior, tends to promote inertia, a lack of responsiveness to changes in the environment.


Whereas individuals have a tendency to lock into one particular interpretation or behavior, group dynamics add a second level of inertia. We have a strong tendency to lock into the same world view, and more generally, to the same behavior and fashions as our peers. This mechanism can cause inertia and shifts in opinions and behavior on massive scales … . Individuals are assumed to adopt an attitude through a cost–benefit argument, assuming a cost of deviating from the overall group tendency (going against peer pressure) and a perceived net utility of adopting the positive attitude. The predictions of such a model are that most individuals favor a passive attitude until a critical point is reached at which a sudden and fast transition to an active attitude toward combatting the problem occurs. This dynamic is not unlike the “paradigm shifts” described by Kuhn where the accumulation of scientific anomalies in data collected using one perspective or set of assumptions results in a sudden and radical shift in scientific perspectives and the birth of a new theory that “explains” the anomalies.

… Even if there is a general feeling that something needs to be done, it can be surprisingly hard to get a group out of the gridlock. In such situations, the “exceptional few” play an important role in catalyzing tipping points. Some individuals appear to be able to mobilize groups to change due to a combination of factors. For instance, they may be particularly well connected, have high social capital, be innovators or early adopters by nature, or have the charisma to cause emotional contagion. The absence of such leaders will make a social group as a whole rigid and weak when adaptation to change is required.

… This implies chances for innovation and manipulation alike. History provides a wealth of examples, ranging from Gandhi to Hitler, that illustrate how, in situations of crisis, the niche for sense making can be filled in very different ways, and the outcome depends very much on who among the “exceptional few” will catalyze new attitudes.

Rigidity and the Collapse of Ancient Societies

… One way to get an idea of how societies may respond to major crises in the future is to look at historical cases.

[The] historical cases suggest some fundamental characteristics of societal response to problems that are deeply rooted in human nature, as revealed by studies of modern human behavior. The main pattern we wish to stress here is the tendency to become increasingly rigid and to adhere to old structures and habits as a sense of crisis increases. Evidence suggests that this may reduce the chance for innovative solutions and much needed change in behavioral patterns.

[It] seems that the tendency to hold stubbornly to habits that led to great success in the past has led numerous societies into trouble over history (Diamond 2004). On a smaller scale, precisely the same dynamics can be observed in companies that “oversimplify” and cling to a narrow set of behaviors that have brought past success.

Zooming in on Paradox: the Efficiency Trap

[The] benefits of more adaptive dynamics seem self-evident. Who would deny that critical attitudes and innovative ideas should be always embraced? Nevertheless, reality is different.

Consider the experiment in which groups had to complete complex assignments. In half the groups, the experimenters introduced a “plant,” someone trained by the experimenter to take a critical attitude (“devil’s advocate”) in reference to group decisions. The groups with the plants consistently outperformed those without the plants, reinforcing the idea that conflict (within limits) plays an important role in problem solving. Nevertheless, in the second round of the experiment, when all groups were asked in a secret ballot to eliminate one team member in order to improve performance, all groups who had devil’s advocates chose to eliminate them, thus eliminating their competitive advantage. Apparently, few groups recognize the value of diversity and conflict in group problem solving. Is this silly, or might there generally be an advantage to coherent groups dancing to the same beat?

Glancing over different fields of research, it seems almost as if there is a fundamental trade-off between two clusters of properties that we could broadly label as “explorative” vs. “efficient” (or “exploitative”). … The exploration and exploitation phases require radically different modes of thinking and acting, indeed they require two different organizational cultures.

[A] compromise between the explorative and the efficient mode is typically avoided, and therefore, is probably a bad idea in general. It would appear that even minimal amounts of exploration will harm efficiency. One could speculate that this is an underlying reason why, in most cases, it may simply feel best for group survival and well-being if all members are in sync and pursuing similar behaviors. Although this may often be functional for the group, it may also severely limit the adaptive capacity.

The tendency to lock into an efficient but non-explorative mode during times of stress implies the risk of a trap. Let us call it the “Efficiency Trap.” It limits the chances of escaping from a crisis through innovative shifts in strategy. One way of depicting these dynamics is to imagine that, in an explorative phase, individuals, groups, or businesses look for an optimum in the “fitness landscape” (Fig. 5). Subsequently, they specialize to become more efficient, improving their particular spot in the fitness landscape further. However, this comes at the cost of their explorative capacity to scan the landscape for alternative good places. This becomes a problem if the landscape gradually changes, causing the originally good spot to end up in a valley of bad fitness. The resulting experienced stress entails further local adaptation, thus improving the local fitness peak slightly, but also increasing myopia and rigidity further.

Remaining Adaptive when we are hard-wired to be consistent

In summary, our review suggests that the evolutionarily important capacity to lock into consistent modes of behavior is deeply rooted. Although it has great advantages, it may also turn into a pathological pattern in human societies if it leads to excessive rigidity in a changing world.  [It] is hard to deny that societies today remain notoriously slow when responding to new problems. If we are faced with runaway climate change or if resource crises deepen, will we be innovative enough to find a way out, and flexible enough to adjust our patterns of living? Maybe so, but as we have seen there are also indications that rigidity in groups sometimes increases in a crisis, and smart “integrated solutions” may become increasingly unlikely in situations of stress. The dynamics of societal response to problems are obviously driven by a complex set of factors. However, even on this large scale, similar patterns can be seen, as has been shown for small groups. For instance, people in nations that live under more stressful conditions … exhibit a pattern of increasing dependence on group norms and authority, and a decreasing dependency on rationality and individual choice, as a basis for making decisions. [Understanding] the mechanisms of inertia is clearly relevant when it comes to developing new strategies to reduce the risk of future crisis. Our review suggests that rigidity is so deeply rooted because it evolved as a way to ensure consistency, which is important to achieve efficient functioning on levels varying from the cell to individuals and groups.

My Comments

  • This may be of much wider importance than climate change.
  • The desire for ‘well-defined and consistent behavior’ ‘limits the ability of persons, groups, and companies to respond to new problems’. So why do we not value diversity, freedom and innovation?

Dave Marsay

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