Vicious Circle: Breaking Free from the Vicious Circle, Understanding Complex Systems for Informed Choices

By Fouad Sabry

What is Vicious Circle

A vicious circle is a complex chain of events that reinforces itself through a feedback loop, resulting in situations that are damaging to the individual. To put it another way, in the short run, it is a system that does not have any tendency toward equilibrium. One example of positive feedback is the way in which each iteration of the cycle strengthens the one that came before it. The momentum of a vicious circle will continue to travel in the same direction until an outside force intervenes to stop the cycle and break the vicious cycle. Hyperinflation is a well-known example of a vicious circle that can occur in the field of economics.

How you will benefit

(I) Insights, and validations about the following topics:

Chapter 1: Vicious circle

Chapter 2: Positive feedback

Chapter 3: Foreclosure

Chapter 4: Nouriel Roubini

Chapter 5: Household debt

Chapter 6: 2000s United States housing bubble

Chapter 7: Jumbo mortgage

Chapter 8: Causal loop diagram

Chapter 9: Leverage-point modeling

Chapter 10: Mortgage loan

Chapter 11: Subprime mortgage crisis

Chapter 12: Timeline of the 2000s United States housing bubble

Chapter 13: Causes of the 2000s United States housing bubble

Chapter 14: Subprime crisis background information

Chapter 15: Regulatory responses to the subprime crisis

Chapter 16: Indirect economic effects of the subprime mortgage crisis

Chapter 17: Subprime mortgage crisis solutions debate

Chapter 18: System archetype

Chapter 19: Strategic default

Chapter 20: Causes of the Great Recession

Chapter 21: Making Home Affordable

(II) Answering the public top questions about vicious circle.

(III) Real world examples for the usage of vicious circle in many fields.

Who this book is for

Professionals, undergraduate and graduate students, enthusiasts, hobbyists, and those who want to go beyond basic knowledge or information for any kind of Vicious Circle.

• Language: English
• Publisher: One Billion Knowledgeable
• Release date: Feb 6, 2024

Book preview

Chapter 1: Vicious circle

A vicious circle (or cycle) is a complex sequence of negative occurrences that perpetuates itself through a feedback loop. In the short term, the system has no tendency toward equilibrium (social, economic, ecological, etc.). Each cycle iteration reinforces the preceding one, which is an example of positive feedback. A vicious loop will continue in its momentum's direction until an outside force intervenes and breaks the cycle. Hyperinflation is a well-known example of a vicious circle in economics.

The contemporary subprime mortgage crisis is a complicated set of vicious loops, both in terms of its origins and its many consequences, most notably the recession of the late 2000s. A specific example is the housing-related circle. As house values collapse, an increasing number of homeowners become underwater when the market worth of their home falls below the amount of their mortgage. This gives an incentive to abandon the property, resulting in an increase in defaults and foreclosures. This further decreases house prices due to an oversupply, continuing the cycle.

By incorporating all stakeholders in ecological area management, a virtuous circle can be created in which improved ecology supports acts that preserve and enhance the region.

The poverty cycle, sharecropping, and the intensification of drought are more instances. Globally, the recurrent outbreaks of the COVID-19 pandemic constitute a vicious cycle.

{End Chapter 1}

Chapter 2: Positive feedback

Positive feedback (exacerbating feedback, self-reinforcing feedback) is a process in a feedback loop that magnifies the impact of a tiny disruption. Thus, one of the impacts of a perturbation on a system is a rise in the perturbation's size. Both principles are essential to science and engineering, including biology, chemistry, and cybernetics.

Causal loop diagram that depicts the causes of a stampede as a positive feedback loop.

Alarm or panic can sometimes be spread by positive feedback among a herd of animals to cause a stampede.

In sociology a network effect can quickly create the positive feedback of a bank run.

Above is a picture of the UK Northern Rock bank run of 2007.

Positive feedback is mathematically defined as a positive loop gain within a closed loop of cause and effect. Thus, positive feedback is in phase with the input in the sense that it contributes to enlarge the input. Positive feedback typically results in system instability. When the loop gain is positive and greater than 1, exponential growth, escalating oscillations, chaotic behavior, and other deviations from equilibrium are usual. Typically, system parameters will accelerate toward extreme levels, which may damage or destroy the system or cause it to enter a new stable state. Positive feedback can be managed by filtering, damping, or limiting system signals, or it can be eliminated or lowered by providing negative feedback.

In digital circuits, positive feedback is used to drive voltages away from intermediate values and into '0' and '1' states. Thermal runaway, on the other hand, is a sort of positive feedback that is capable of destroying semiconductor junctions. Positive feedback in chemical reactions can enhance the reaction rate and, in extreme circumstances, cause explosions. Positive feedback in mechanical design causes tipping-point or over-centre devices, such as those in switches and locking pliers, to snap into place. Uncontrolled, it can cause the collapse of bridges. In economic systems, positive feedback can generate boom-and-bust cycles. A common example of positive feedback is the loud screeching or howling produced by audio feedback in public address systems: the microphone picks up sound from its own loudspeakers, amplifies it, and then transmits it back via the speakers.

Platelet clotting demonstrates positive feedback.

The injured blood artery wall releases substances that, by platelet aggregation, induce the formation of a blood clot.

As more platelets congregate,, The release of additional substances accelerates the process.

Until the blood vessel wall is completely sealed and the positive feedback loop terminates, the process accelerates.

The graph's exponential structure depicts the positive feedback process.

Positive feedback strengthens or amplifies an impact by influencing the process that produced it. For instance, the system gain is enhanced when a portion of an electronic output signal returns to the input and is in phase with it. A crucial characteristic of positive feedback is the amplification of tiny disruptions. When a system undergoes a change, positive feedback encourages additional change in the same direction.

A basic feedback system can be represented by this block diagram.

The plus sign is an adder in the diagram, whereas A and B are arbitrary causal functions.

The diagram illustrates a simple feedback loop. If the loop gain AB is positive, then positive or regenerative feedback is present.

If the functions A and B are linear and AB is less than one, then the overall system gain from input to output is finite, but can become extremely large as AB approaches one. In this scenario, the overall or closed loop gain from input to output may be demonstrated to be:

G_c = A/(1-AB)

When AB is more than 1, the system is unstable and lacks a well-defined gain; the gain may be termed unlimited.

Consequently, state changes can be convergent or divergent based on the input. Positive feedback has the effect of amplifying changes, so that modest perturbations can result in large ones.

In the event that a system in equilibrium with positive feedback to any change from its current state is unstable, it is said to be in an unstable equilibrium. The amount of the forces acting to drive such a system away from equilibrium is proportional to the system's distance from equilibrium.

Positive feedback does not necessarily imply instability of an equilibrium; for instance, positive-feedback systems may have stable on and off states.

Hysteresis causes the output value to depend on the history of the input

In a Schmitt trigger circuit, Feedback to the non-inverting input of an amplifier pushes the output directly away from the applied voltage toward the maximum or minimum voltage the amplifier is capable of producing.

In the actual world, positive feedback loops often do not result in exponential growth, but are instead regulated by limiting influences. In accordance with Donella Meadows:

Sources of growth are positive feedback loops., explosion, erosion, and systemic breakdown.

A system with an unregulated positive feedback loop will eventually self-destruct.

That’s why there are so few of them.

Usually, a negative loop will activate sooner or later."

Positive feedback can cause hysteresis, in which the starting point influences the final state of the system. When the feedback loop gain is greater than 1, the output goes away from the input: if it is above the input, it moves towards the nearest positive limit, and if it is below the input, it moves towards the nearest negative limit.

Once the limit is reached, stability will ensue. Nevertheless, if the input exceeds the limit, the feedback changes sign and the output moves in the opposite direction until it reaches the opposite limit. Therefore, the system exhibits bistable behavior.

Before World War II, the labels positive and negative were initially applied to comments. With the advent of the regenerative circuit in the 1920s, the concept of positive feedback was already well-established. In his landmark 1934 paper, Harold Stephen Black first describes the use of negative feedback in electrical amplifiers. Apparently, Black:

Positive feed-back enhances the gain of the amplifier, whereas negative feed-back decreases it.

According to Mindell (2002), confusion regarding the words occurred shortly thereafter:

Friis and Jensen had made the same distinction between positive and negative feedback that Black did, based not on the sign of the feedback itself but rather on its effect on the amplifier’s gain.

In contrast, Bode and Nyquist, when they built on Black’s work, referred to negative feedback as the opposite of positive feedback.

Black had difficulty persuading others of the usefulness of his innovation due in part to ambiguity surrounding basic definitions.

A vintage style regenerative radio receiver.

Due to the strategic use of positive reinforcement, A single vacuum tube or valve is capable of providing adequate amplification (centre).

In 1914, regenerative circuits were developed and patented. In this manner, a signal that would ordinarily have a gain of 20 to 50 can be amplified 20,000 to 100,000 times in a single stage. At these extremely high gains, regenerative amplifiers are prone to instability and oscillation. The radio operator must be willing to continuously adjust the quantity of feedback for optimal reception. Modern radio receivers use the superheterodyne design, which features a greater number of amplification stages but more stable functioning and no positive feedback.

In electronic oscillators, the oscillation that can occur in a regenerative radio circuit is utilized. By utilizing tuned circuits or a piezoelectric crystal (often quartz), the signal enhanced by positive feedback remains sinusoidal and linear. There are numerous designs for harmonic oscillators, such as the Armstrong oscillator, Hartley oscillator, Colpitts oscillator, and the Wien bridge oscillator. All of them use positive feedback to generate oscillations.

Several electrical circuits, especially amplifiers, include nasty comments.

This diminishes their gain, whereas it enhances their linearity, input impedance, output impedance, and bandwidth, all of these factors are stabilized,, as well as the closed-loop gain.

Additionally, these factors become less reliant on the specifics of the amplification device, and increasingly dependent on feedback components, which are less susceptible to variation due to manufacturing tolerance, temperature and age.

The difference between positive and negative AC feedback is one of phase: if the signal is reflected out of phase, If it is out of phase, the feedback is negative; otherwise, it is positive.

A issue for designers of amplifiers employing negative feedback is that certain circuit components will produce phase shift in the feedback