Known effects, phenomena, paradoxes
Examples of self reinforcing and self multiplying feedback loops that widen gaps and foster accumulation, and other effects that corrupt a system or produces unintended consequences. That it would be interesting to interpret using patterns. Some may actually be the result of the same phenomenon, i.e. combination of patterns, or constitute elementary patterns themselves.

The Matthew effect: success helps gain access to resources which in turn results in further success and resources. Credit is given to those who are already famous (or rich), also called preferential attachment (attraction of largest hubs). Example in peer review, ranking by ‘likes’ or popularity, star system, meritocracy, winner take all markets. Same phenomenon happens in reverse with scapegoating, bullying, swiftboating campaigns. This is normative and may stifle difference or disruptive innovation.
> Feedback driven by reputation, ‘winner’ attraction


The Network effect: When network effect is present, the value of a product or service is dependent on the number of others using it. Each new entrant adds value to the whole network. Over time, positive network effects can create a bandwagon effect as the network becomes more valuable and more people join, in a positive feedback loop. That’s why most of us are still on facebook… Newer networks have more difficulty to attract.
> Feedback driven by critical mass attraction

The bandwagon effect or herd behavior:
"the probability of any individual adopting a behavior increases with the proportion who have already done so". People chose the most visible, obvious, ‘attractive’ options. Examples in rankings, recommended purchases, likes, SEO, best practices. In management, and investment optimization, ‘winning models’ are over-applied, reducing the diversity of behaviors, and in the end of competitive advantage.
> Feedback driven by Imitation

Self-fulfilling prophecy:
a prediction that directly or indirectly causes itself to become true, by the very terms of the prophecy itself, due to positive feedback between belief and behavior that brings the behavior to reality. Examples: Bear or bull markets. Assuming people cannot be trusted makes them more dishonest, assuming people are driven by self-interest makes them worry more of their self interest. Behavioral engineering plays on this.
> Assumption feedback
 
These effects all overlap and feed into each other, amplified by form, scope (distribution), intensity (pressure) and frequency of communication that influence propagation.

Consequences of reinforcing feedback loops


Pareto principle:
(also known as the 80–20 rule, the law of the vital few, and the principle of factor sparsity) for many events, roughly 80% of the effects come from 20% of the causes/occurrences.  Efforts tend to concentrate on the 20%.

Power law: a functional relationship between two quantities, where one quantity varies as a power or exponentiation of another. "In systems where many people are free to choose between many options, a small subset of the whole will get a disproportionate amount of traffic (or attention, or income), even if no members of the system actively work towards such an outcome. The very act of choosing, spread widely enough and freely enough, creates a power law distribution.” (Clay Shirky)

Cumulative advantage: once a social agent gains a small advantage over other agents, that advantage will compound over time into an increasingly larger advantage, attracting an increasing amount of resources.

  

Examples of phenomena that can be seen when an equilibrium frame is not applied. From Brian Arthur Complexity Economics: a different framework for economic thought pp 9-11 Abstracted here.

Self-reinforcing asset-price changes (aka bubbles and crashes)
As wins or losses are based on forecast capacity, investors typically generate (or discover) their own forecasting methods, try out promising ones, drop those that don’t work, and periodically generate new ones to replace them. The stock price forms from their bids and offers, and thus ultimately from agents’ forecasts. Our market becomes an ecology of forecasting methods that either succeed or are winnowed out, an ecology that perpetually changes as this happens. And we see several phenomena, chief among them, spontaneous bubbles and crashes. If the price of a stock rises for a while from a first type of forecast, investors will buy in thus validating it, which may cause a further rise. Eventually this drives the price high enough to trigger a second type of forecast. Investors holding these sell, the price drops, which switches off the upward forecasts, causing other investors to sell too, and a crash ensues. The scale and duration of such disruptions vary, they happen randomly in time, so they cannot be predicted. What can be predicted is that such phenomena will occur, and will have certain probability distributions of size and scale. (how does this compare/combine with ‘self fulfilling prophecy’?)

Clustered volatility.
This is the appearance of random periods of low activity followed by periods of high activity. In our artificial market these show up as periods of low and high price volatility. Low volatility reigns when agents’ forecasts are working reasonably well mutually; then there is little incentive to change them or the results they produce. High volatility happens when some agent or group of agents “discover” better predictors. This perturbs the overall pattern, so that other investors have to change their predictors to readapt, causing further perturbation and further re-adaptation. The result is a period of intense readjustment or volatility. Such random periods of low volatility alternating with high volatility show up in actual financial market data, where they are called GARCH behavior.

Sudden percolation.
When a transmissible change happens somewhere in a network, if the network is sparsely connected the change will sooner or later peter out for lack of onward connections. If the network is densely connected, the change will propagate and continue to propagate. In a network of banks, an individual bank might discover it holds distressed assets. It then comes under pressure to increase its liquidity and calls on its counterparty banks. These in turn come under pressure to increase their liquidity and call on their counterparties, and so the distress cascades across the network. Such events can cause serious damage. They peter out in a low-connection network, but propagate—or percolate—for long periods as the degree of connection passes some point and gets large.

Also interesting to crack are paradoxes:

The Jevons Paradox

In economics, the Jevons paradox, sometimes Jevons effect) is the proposition that as technology progresses, the increase in efficiency with which a resource is used tends to increase (rather than decrease) the rate of consumption of that resource.

This however is not a 'systematic' unescapable consequence of increases in energy efficiency. The PL should help express visually in which conditions (example freed outflow of the resource on 'offer' that seeks an outlet, i.e analogy with open tap). With a circular economy and output tap closed, or the availability of an alternative clean renewable resource, the jevons effect does not kick in.

 

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Known effects, phenomena, paradoxes
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Link[1] Systems Archetypes - Success to the successful

Author: Systems-Thinking.org
Cited by: Helene Finidori 2:30 PM 13 October 2014 GMT
Citerank: (1) 330250Resources on systemic phenomena, their causes and effectsGame theory, algorithms, crowd induced effects, systems dynamics archetypes609FDDBE
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Link[2] Systems archetypes - Accidental adversaries

Author: Sstems Wiki - Gene Bellinger
Cited by: Helene Finidori 2:30 PM 13 October 2014 GMT
Citerank: (1) 330250Resources on systemic phenomena, their causes and effectsGame theory, algorithms, crowd induced effects, systems dynamics archetypes609FDDBE
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Excerpt / Summary
A structure where two entities which would be in a synergistic growth relationship end up limiting each others results because of their own activities.
Link[3] Systems Archetypes - Limits to growth & atractiveness principles

Author: Systems Wiki - Gene Belliger
Cited by: Helene Finidori 2:30 PM 13 October 2014 GMT
Citerank: (1) 330250Resources on systemic phenomena, their causes and effectsGame theory, algorithms, crowd induced effects, systems dynamics archetypes609FDDBE
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Excerpt / Summary
One or more 'limits to growth' factors. Balancing loops that come to hinder a reinforcing loop.
Link[4] Systemes archetypes

Author: Systems Wiki - Gene Bellinger
Cited by: Helene Finidori 2:30 PM 13 October 2014 GMT
Citerank: (1) 330250Resources on systemic phenomena, their causes and effectsGame theory, algorithms, crowd induced effects, systems dynamics archetypes609FDDBE
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Excerpt / Summary
More archetypes
Link[5] Continuous Improvement Cycle PDCA/PDSA

Author: Wikipedia, W.E. Deming
Cited by: Poor Richard 2:30 PM 13 October 2014 GMT
Citerank: (1) 330250Resources on systemic phenomena, their causes and effectsGame theory, algorithms, crowd induced effects, systems dynamics archetypes609FDDBE
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Excerpt / Summary
"PDCA (plan–do–check–act or plan–do–check–adjust) is an iterative four-step management method used in business for the control and continuous improvement of processes and products. It is also known as the Deming circle/cycle/wheel, Shewhart cycle, control circle/cycle, or plan–do–study–act (PDSA). "
Link[6] Peter Principle

Author: Wikipedia, Laurence J. Peter
Cited by: Poor Richard 2:30 PM 13 October 2014 GMT
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Excerpt / Summary
Peter Principle -- one is promoted until duties exceed one's competence

1969 book The Peter Principle: Why Things Always Go Wrong by Laurence J. Peter
Link[7] Control Theory in sociology

Author: Wikipedia
Cited by: Poor Richard 2:30 PM 13 October 2014 GMT
Citerank: (1) 330250Resources on systemic phenomena, their causes and effectsGame theory, algorithms, crowd induced effects, systems dynamics archetypes609FDDBE
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Control Theory in sociology is the idea that two control systems—inner controls and outer controls—work against our tendencies to deviate. Control Theory can either be classified as centralized or decentralized or neither. Decentralized control is considered market control. Centralized control is considered bureaucratic control. Some types of control such as clan control are considered to be a mixture of both decentralized and centralized control.
Link[8] Customer feedback management (CFM)

Author: Wikipedia
Cited by: Poor Richard 2:30 PM 13 October 2014 GMT
Citerank: (1) 330250Resources on systemic phenomena, their causes and effectsGame theory, algorithms, crowd induced effects, systems dynamics archetypes609FDDBE
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Excerpt / Summary
Customer feedback management (CFM) online services are web applications that allow businesses to manage user suggestions and complaints in a structured fashion. A 2011 study conducted by Aberdeen Group showed that companies using customer feedback management services and social media monitoring have a 15% better customer retention rate.
Link[9] Control–Feedback–Abort (CFA) loop

Author: Wikipedia
Cited by: Poor Richard 2:30 PM 13 October 2014 GMT
Citerank: (1) 330250Resources on systemic phenomena, their causes and effectsGame theory, algorithms, crowd induced effects, systems dynamics archetypes609FDDBE
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Too often systems fail, sometimes leading to significant loss of life, fortunes and confidence in the provider of a product or service. It was determined that a simple and useful tool was needed to help in the analysis of interactions of groups and systems to determine possible unexpected consequences. The tool didn’t need to provide every possible outcome of the interactions but needed to provide a means for analysts and product/service development stakeholders to evaluate the potential risks associated with implementing new functionality in a system. They needed a brainstorming tool to help ascertain if a concept was viable from a business perspective. The control–feedback–abort loop and the analysis diagram is one such tool that has helped organizations analyze their system workflows and workflow exceptions.
Link[10] Feedback in Social Sciences

Author: Wikipedia
Cited by: Poor Richard 2:30 PM 13 October 2014 GMT
Citerank: (1) 330250Resources on systemic phenomena, their causes and effectsGame theory, algorithms, crowd induced effects, systems dynamics archetypes609FDDBE
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Education

In the majority of universities, teachers decide learning objectives and feedbacks to students.

Types of reinforcement / Reinforcement Example

Confirmation Your answer was correct.
Corrective Your answer was incorrect. The correct answer was Jefferson.
Explanatory Your answer was incorrect because Carter was from Georgia; only
Jefferson called Virginia home.
Diagnostic Your answer was incorrect. Extra instruction on the home states of
past presidents might be helpful.
Elaborative Your answer, Jefferson, was correct. The University of Virginia, a
campus rich with Jeffersonian architecture and writings, is sometimes
referred to as "Mr. Jefferson's University".

A different application of feedback in education is the system for "continuous improvement" of engineering curricula monitored by the Accreditation Board for Engineering and Technology (ABET).

Examples of feedback in organizations:

Financial audit
Performance appraisal
Shareholders' meeting
Marketing research
360-degree feedback
Walkout
Lockout

In Psychology

One application of feedback in psychology, education, and organizations is feedback intervention; defined as "actions taken by (an) external agent(s) to provide information regarding some aspect(s) of one's task performance."[38] Despite common beliefs that such feedback is typically effective, Kluger & DeNisi (1996) reported a meta-analysis that showed that in 38% of the experiments published between 1905 and 1992, feedback caused a decline in performance.[38] Moreover, the decline in performance was not related to whether the feedback was positive or negative (i.e., encouraging or critical). This result was explained with Higgins' self-discrepancy theory. Specifically, positive feedback seems to improve motivation and performance when people are promotion-focused (doing things out of a desire; working on a task requiring creativity.) Whereas negative feedback improves performance when people are prevention-focused (doing things out of an obligation; working on a task requiring vigilance.)
Link[11] System dynamics

Author: Wikipedia
Cited by: Poor Richard 2:30 PM 13 October 2014 GMT
Citerank: (1) 330250Resources on systemic phenomena, their causes and effectsGame theory, algorithms, crowd induced effects, systems dynamics archetypes609FDDBE
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System dynamics is an approach to understanding the behaviour of complex systems over time. It deals with internal feedback loops and time delays that affect the behaviour of the entire system.[1] What makes using system dynamics different from other approaches to studying complex systems is the use of feedback loops and stocks and flows. These elements help describe how even seemingly simple systems display baffling nonlinearity.

Causal loop diagrams
https://upload.wikimed...

In the system dynamics methodology, a problem or a system (e.g., ecosystem, political system or mechanical system) is first represented as a causal loop diagram.[4] A causal loop diagram is a simple map of a system with all its constituent components and their interactions. By capturing interactions and consequently the feedback loops (see figure below), a causal loop diagram reveals the structure of a system. By understanding the structure of a system, it becomes possible to ascertain a system’s behavior over a certain time period

[There are many more topics, equations, feedback diagrams, etc. in this article. ]
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Known effects, phenomena, paradoxes