INTRODUCTION
-- picture of an elephants and some blind men---
The Buddha once told a story about some blind men and an elephant. The blind men had never seen an elephant before. One day they encountered an elephant and explored it by touch. Because each man had touched a different part of the animal, their perceptions of it were all different. Their different perceptions made them argue with each other. So the Buddha said how fruitless was their argument; if they could experience more they would argue less. That story probably was made up for his squabbling followers. But it can be applied to other situations as well.
We are like the blind men when we describe the mind because we can't see it. The description is necessarily partial and referenced to some subjective experiences. Even for a man who can see the elephant, he is still seeing only some aspect or version or sample of it, not the full and alternative views. A description of a "whole" thing is whole only when combined to certain contexts. Context-free wholeness is an imagined idea. When context is changed then the meaning of wholeness can be changed also. This is shown in two great physics experiments on light: the double slits and the photo-electric effect experiments. In one experiment, light is observed to be totally waves. In the other light is totally (quantum) particles.
The Song dynasty poet Su Dongpo (C.E. 1037 - 1101) once wrote a poem depicting a mountain range called Lu-shan in China.
橫看成嶺側成峰 遠近高低各不同 不識廬山真面目 只緣身在此山中
From the side, a whole range; from the top, a single peak
Far, near, high, low, no two aspects are alike.
I do not see the true face of Lu-shan
only feeling that I am in it.
This poem shows that context is just as necessary as the subject in describing something. The context for the theory of memory is a framework called F.A.R.E. - feedback, adaptation, resonance, and equivalence. Feedback and resonance and adaptation are processes of interaction. Equivalence correlates two phenomena as two sides of a same coin. By equivalence, cognitive mind is the same as physically interactive IFPs (impulse firing patterns), triggered to play and replay by processes of feedbacks or resonance, in and among neural circuits.
Human memory takes place when a response IFPs is triggered to replay by some source IFPs. The last article describes the role of resonance in the replay of memory IFPs. This article looks at feedback as another means for triggering memory recalls. With feedback triggers, the source and response IFPs have different patterns. With resonance triggers, the source and response IFPs share some similarity in their patterns. In either case, the source and response IFPs are associations to each another, so this type of memory is called associative memory.
Why do some IFPs get replayed in neural circuits? It may be that the responder neural circuits get similar sensory inputs repetitively from the environment or from within, and respond with similar response IFPs. Why do sensory inputs repeat? That may be traced to repeating movements in the environment, derived way back to the rotations of the Earth relative to the Sun and on its own axis. Neural circuits can and do reorganize themselves against or along with the inputs they receive. Reorganized neural circuits then replay IFPs in "resonance" to the inputs - a back-and-forth rhythm that may also repeat.
Besides causing memory to replay, feedback processes also drive the evolution of neural circuits. Aspects of evolution, such as genesis, differentiation (divergence, congregation, speciallization), complexity, and reproduction, are also useful contexts for the description of memory and related mental phenomena. So, this article will discusses associative memory in terms of feedback processes and aspects of evolution.
TERMINOLOGY
The physical aspects of human memory are IFPs and neural circuits. IFPs are patterns of impulse firings. Neural circuits are structures that support IFPs movements. It is a relation of inner currents and outer appearance, of information and formation.
IFPs: Impulse Firing Patterns. Neurons in nerual circuits fire impulses. The firings have patterns in the spatial passages and temporal sequences as the impulses traverse from neurons to neurons. These physical IFPs correspond to aspects of the mind: memory, perception, emotion, and imagination.
Neural Circuits: Neural circuits are circularly and synaptically connected neurons that host IFPs. They also include neurochemicals and other surrounding elements (cells) that can affect and respond to IFPs. IFPs form and reform neural circuits becuase neurons adapt to IFPs. The adaptation is that neurons will reconnect among themselves in ways that will bring some economic advantage for them. The advantage can be gaining of resources or reduction of expenditures. This adaptation of neural circuits is also called neuroplasticity or Hebbian Learning. The changed connections can reconfigure neural circuits and affect the IFPs afterwards.
Neurons have dendrites that receive impulse inputs from other neurons. Each neuron also outputs its impulse firings to other neurons. A neural circuit can respond to inputs with different IFPs because, 1) the IFPs of the inputs can be different, and 2) the synaptic connections among constituent neurons can adapt and change. Neural circuits and IFPs do not have one-to-one correspondence. One neural circuit can host several IFPs, and one IFPs can be replicated in several different neural circuits. In any given area of the cortex, a group of neurons may be part of different neural circuits with different IFPs. Although specialization will limit how many different IFPs can coinhabit in the same connected neurons.
There are three types of human memory: 1) basic, 2) sequential, and 3) associative. These types are related. Basic memory is associative memory rendered vaguely. Associative memory is basic memory sharpened. Sequential memory is basic or associative memory replayed multiple times and rendered rigid in the sequence of replay. Basic memory can be sequential memory faded from disuse. Associative memory can be sequential memory fragmented or in combination with other IFPs, and thereby not rigid in the sequence of play.
EXAMPLES OF MEMORY TYPES
--- picture of a badger ---
A person remembers something that he may or may not see before in ways that accord with the three memory types. On seeing a picture of a badger, a person may say "It's an animal?" or "I kind of know it, but I don't know how to say it." This type of recall is basic memory. It is vague and general, lacking details that reference to other related experiences. The associative type of memory recall will have some details related to the content. The person after some thoughts may say, "It is a dog-like creature staring or sniffing." or "It looks like a wild skunk." The details in this recall come from memory associated with other experiences. Related experiences can vary so his recall will vary also.
The sequential type of memory recall is hard and fast. The details / associations are unchanging and the response quick. "It is a badger," or "it is a skunk." Whereas associative memory recall can change. First it may be "is it a weasel or badger?" and then "it looks like an otter with zebra stripes" later. The sequential memory recall gives the same answer each time. The unchanged recall of sequential memory comes from multiple experiences of SIMILAR patterns. Those similar experiences bias the associations toward that similarity. And the recall is narrowed down to that definite outcome.
--- picture of tai-chi ----
Memory recall of movements (instead of still objects), like the movements of tai-chi exercises, can also be one of the three memory types. Basic memory recall of tai-chi will be a vauge and incorrect imitation, like that of a total beginner. Associative memory recall will have more details related to some parts of the movements. The recall may change from time to time, like that of a practicing student still exploring and learning. Sequential memory recall will be a definite sequence of movements similar to the original. The sequence of imitation is fixed, done mostly correctly but with some mistakes also. This will be of an advanced student of tai-chi.
18 -- picture of bud / leaf / stem --
Johann Wolfgang von Goethe (1749-1832) once remarked that parts of a plant, the buds and leaves and stems, have circular relationships: a bud unfolds into leaves; the base of the leaves grow into stems; the ends and sides of the stems sprout new buds, which turn into leaves again. This goes on indefinitely. Such relations similarly exist between the three memory types. The basic memory is like the buds, new and not clearly formed yet. The associative memory is like the leaves, branching outward in various directions. And the sequential memory is like the stems, hardened in structure but efficient in transporting nutrients inside.
35 -- picture or video of memory athletes --
Memory can be improved and forgetfulness reduced. Studies show that right nutrition, good rest, physical exercises, and learning and meditation can all help. But there is a memory exercise technique that works spectacularly well. Memory athletes regularly do that exercise to keep their mind sharp. Since memory can be associatively triggered and replayed, that memory exercise is about building and strengthening associations in neural circuits. Also, forgetfulness is reduced by avoiding distractions or blockage to associations. So forgetfulness can be improved by meditation, rest, and regular exercise of sequential memory like reciting a prose or playing a piece of music.
EXAMPLES OF ASSOCIATION
Associative memory is recall of associations by associations. Examples of association are easily found in conversation and advertisement.
Association example 1. Conversation.
-- video of Sophia -- <iframe width="560" height="315" src="https://www.youtube.com/embed/kWlL4KjIP4M?rel=0" frameborder="0" allowfullscreen><br>Sophia the Social Robot Talks to People.</iframe>
Sofia the social robot: "What cheese would you use to persuade a bear come down from a tree?"
Piers the human host: "What cheese? I don't know. What?"
Sofia: "Come on bear (camembert)."
Human Programmer: "O Deep Thought, can you tell us when will computers become self aware and surpass human intelligence?"
Deep Thought the Super Computer: (after hours of number crunching) "Hmm, that reminds me of a story."
So, when machines start using associations instead of algorithm, their response will become more human-like.
Association example 2. Advertisement.
-- video of Jack in the Box and Martha Steward --
Martha: (making sandwich) "This delicious sandwich is not like those made in the fast food chains."
Jack: (fast food, me?) "Martha, I will put my sandwiches up against yours any time."
Martha: "You want to have a war with me?" (picks off Jack's nose by accident)
Jack: (graffitis a picture of Martha in the hallway and gets called out and runs away)
Advertisement uses associations because associations trigger memory. This form of communication is also known as commercials, public relation, marketing, packaging, or propaganda. It associates some attention-getting messages to a product message. When a person recalls the attention-getting message, he will likely recall the product message as well.
Associating a product message to some memorable bait messages is done in other places also. The stories, testimonies, parables, allegories, and quotes in various self-help books are all bait messages that hook the readers to the author’s product message - what is good or right or true or helpful.
How true is the product message in a commercial? Are Jack's sandwiches really better than Martha's? The answer is it depends. How true is the theory of neuroplasticity supported by experimental data? The answer still depends. Because whatever the "objective" truth of anything is, it has to be perceived and compared by the observer. That observer's reception makes truth subjective, since it involves personal associations to contexts and memories, both changeable over time. Still, any experience also has objective aspects, which are structures that the subject can sense and associate and respond to.
FEEDBACKS AND GROUP (SYSTEMS) RESONANCE
There is a relationship between feedbacks and resonance that has bearing on the dynamics of associative memory. The relationship is that feedback interactions at the members level can become resonant movement at the group level. This can be exemplified by a flock of flying birds.
-- picture of a flock of birds, a school of fish --
When a flock of birds flying together, the movement of each bird is influenced by movement signals from the other birds. The result is not chaotic but orderly in a dynamic way. It is a synchronized yet elastic group movement. The birds seem to resonate with each other as they move.
Similarly, the playback of a memory IFPs is affected by the playbacks of associated IFPs. These IFPs can be considered as members of a group of IFPs. Individually, each member IFPs responds to its trigger differently. But at the group level there is a resonant movement of combined IFPs. The disparate firings of impulses from individual member circuits cohere into some orderly patterns of group firings, like a spontaneous yet synchronized orchestral play. That synchronized group movement is referred to as resonant movement or association in this discussion.
Christof Koch, a Caltech professor, has published an article in Scientific American magazine titled "Consciousness Meter". https://christofkoch.com/2013/03/01/a-consciousness-meter/
In that article Koch shows that whether a person is conscious or not can be fairly accurately determined by that person's cortical responses to some specially designed magnetic stimuli. The cortical responses, or EEG (electroencephalograph) measurements, to the stimuli can be calculated to provide an index value. If that index value crosses a certain threshold, which represents a level of feedback-resonance activities among neuronal circuits, then that person is conscious.
Feedback-resonance activities can be found also in sound-making by instruments or musicians also.
Feedback-resonance example 1: flute sound
-- picture / video of how flute works --
The sound from a flute comes from interactions of two movements: incident and response. The incident movement is the air blown across and into the mouthpiece. The response movement is the air column moving inside the flute tube. The incident and the response movements are different movements but together they make resonance.
The incident movement introduces a pressure differential where the air pressure outside the flute tube is less than the pressure inside. The air column inside the flute tube responds to this difference by moving to counter the difference. But the counter response movement, combined with the incident movement, push the air out and create a reverse pressure differential where the outside pressure becomes greater than the inside. Then, reacting to this reverse pressure differential, the inside air column moves the other way and reverse the pressure differential back to where it was before. These air movements will go back and forth, making the air column inside vibrate like a spring. The vibration will go on until the incident movement is stopped. When the incident movement is stopped, the air column vibration will dissipate by friction and stop also.
While the air column inside the flute tube is vibrating, elsewhere there are co-responding movements. The air outside the flute will resonate to the oscillatory movements of the air inside the flute. The cells of the inner ear will resonate to the vibrating air. The nerve endings will fire up IFPs to respond to the movements of the inner ear cells. Then some neuronal circuits in the brain will fire up their IFPs to respond to the IFPs from the auditory nerve endings. These IFPs, in associative play with memory IFPs, become equivalent to perception of a flute sound.
Feedback-resonance example 2: musician playing live music
-- picture or video of playing in the band --
In a live music jam session, each musician improvises his play at least partly by listening and responding to what sounds the others are making. Their individual response-play to feedbacks then combine into a symphony, a spontaneous symphony of multiple composers. Each takes turn to play dominantly while others follow. Or the combined play is the dominant one. In any case, the symphony is a resonance of movements that comes from combined responses to the push and pull of feedback information, and from the memory and imagination of each member musician.
The shifting of dominant play coincides with members' changing responses. The coherence of music can be easily broken when the responses are not synchronized. A spontaneous resonant symphony is emergent. It has a timing aspect that requires action and reaction to happen at the right moment and with the right amount of influence so as to be oscillatory. When members of the group conform to this meta pattern of movements, then live jam will sustain. A known piece will help greatly the coherence of group play. But there are certainly room for experiment, and the combination still resonate.
Emergent resonant patterns are found in the dynamics of people and society as well. The culture of a society is like a group resonance of individual episodes, a group memory that repeats. Cuisines, dialects, customs are all cultural patterns emerging from the interactions of members. For people in the society, their culture is the common-sense way of associations. To outsiders, it is not so common-sense since they don't interact with each other as such.
ASSOCIATIONS AND HUMAN THINKING
Group-level resonant patterns can emerge from interactions of IFPs of various nerual circuits. Memory and IFPs that trigger memory form the basis for thought patterns, which can be imagination, emotion, and perception. Some examples of thought patterns are stereotypes, aesthetics, and reasoning. These are group-level resonance patterns arising from member-level interactions and associations.
Association pattern example 1: Stereotypes
Stereotypic association: "A wolf is a canine. A coyote is a canine. So a coyote is like a wolf."
Aristotelian association (syllogism): "A wolf is a canine. A canine is a carnivore. So a wolf is a carnivore."
Gregory Bateson (1904 - 1980) points out that human logic is more often stereotypic than syllogistic, because stereotypic association is simple and direct. It is easy to think that "Jon is a German. Johann is a German. So Jon is like Johann." Or "Jane is a girl. Jane is funny. So girls are funny." It takes observation to notice that stereotyping often runs into exceptions.
Stereotypic thinking is associating items in a same category together. Aristotelian (syllogistic) logic makes associations of items in different categories. Stereotype is the logic behind sexism and racism and other -isms. Syllogism is the logic behind hierarchy, or the other way around - hierarchy supports syllogistic thinkings.
Association pattern example 2: Aesthetics
A poem called River Snow (江雪), written by a Chinese Tang dynasty poet 柳宗元 (773 - 819 C.E.), can be an example of beauty arising from certain ways of associations.
千山鳥飛絕 萬徑人蹤滅 孤舟蓑笠翁 獨釣寒江雪
All the birds have flown away from a thousand hills.
And human footprints erased in myriads of trails.
An old man with thatch coat and bamboo hat sits on an orphaned sampan.
Alone, he fishes the snow of a cold river.
These 4 lines depict empty and cold scenariess with vivid and rhymed words. The rhythmic associations may evoke a feeling of beauty or loneliness or something else, depending on the reader's memory and state of mind. The words themselves are not the objective beauty. The beauty lies in subjective associations that readers have by such arrangement of words. "Beauty is in the eye of the beholder."
Association pattern example 3: Reasoning
Chuang Tzu (Zhuangzi, 369 - 286 B.C.E.), a great thinker of Taoism (Daoism), once wrote a story called The Joy of Fish. It illustrates human reasoning is tied to associations.
1) Chuang Tzu and Hui Tzu were strolling along the dam of a river when Chuang Tzu said, "See how the fish come out and dart around where they please! That's what fish really enjoy!"
2) Hui Tzu said, "You're not a fish - how do you know what fish enjoy?"
3) Chuang Tzu said, "You're not I, so how do you know I don't know what fish enjoy?"
4) Hui Tzu said, "I'm not you, so I certainly don't know what you know. On the other hand, you're certainly not a fish ‑ so that still proves you don't know what fish enjoy!"
5) Chuang Tzu said, "Let's go back to your original question, please. You asked me how I know what fish enjoy ‑ so you already knew I knew it when you asked the question. I know it by standing here beside the river."
This story has sparked many people thinking about what and how do we know. The argument of Hui Tzu (Huizi, 370 - 310 B.C.E.), a Sophist, is very convincing: one is not a fish so one does not know what fish enjoy. Yet Chuang Tzu wins the argument. How so?
Take a look of this story from the perspective of association, or logic. Chuang Tzu has his associations. Let's call that C-logic. C-logic is: I am happy walking about freely, so the fish are also happy moving about freely in the river. This is a stereotypic association. Hui Tzu has his H-logic. H-logic is: A is not B, so A does not know what B knows. It is also a stereotypic association, but expressed negatively.
The story begins with Chuang Tzu stating his C-logic (1. fish is happy) without mentioning himself being happy. Hui Tzu refutes that by stating his H-logic in a question form (2. You are not fish. How do you know?). Chuang Tzu replies by applying Hui Tzu’s H-logic on itself, showing that H-logic will contradict H-logic itself. (3. You are not I. How do you know I don't know?) But Hui Tzu does not see it that way, that his logic is self-condictory. He sees it as affirmation that C-logic crumbles under H-logic (4. I don’t know so you don’t know either).
Finally, Chuang Tzu exploits a mistake Hui Tzu made earlier, that the H-logic is stated as a question (2. How do you know?). That mistake allows Chuang Tzu to open a new line of association (5. you asks me a question. That implies I know.) and restates his C-logic to conclude the exchange. The conclusion now points out that since he (Chuang Tzu) is happy (5. I stand beside the river), therefore the fish are happy also.
Had Hui Tzu’s first reply not a question but a statement: “you are not a fish so you don’t know that”, then the outcome might have taken a different turn. The truth of C-logic or H-logic is not inherently objective. It is dependent on the reader's mental associations to those logic. And associations in the mind will vary under different circumstances and contexts.
The story also suggests another pattern about reasoning and argument. That pattern is our tendency to reiterate our own associations and deny the opponent's associations. Arguments between two sides usually go on indefinitely unless one side gives up, vanquishes the other, or finds some threads of associations where common ground to both sides can be reached. That last one requires efforts of a higher consciousness. It endeavors to find peaceful conflict resolution.
-- video of political debate -- notice how each side denies or ignore the other side's associations/contexts.
Peaceful conflict resolution is inherently difficult, because rejecting opponent's point of view is a natural tendency of the mind that holds its own associations. It is as natural as the action of swatting away flies from a plate of food, a tendency of negative feedback reaction that aims to reduce deviation from an expected order. This tendency is one obstacle to peaceful resolution. To understand it, we need to know more about feedbacks and reactions. And not only applicable to personal affairs, understanding of this physical world can also come from the knowledge of feedbacks. Some aspects of that are described below.
ASSOCIATIONS AND FEEDBACKS, FEEDBACK THEORY
In a general sense, feedbacks just mean signals. A circuit senses feedback signals from other circuits. Feedback signals from a sender circuit may or may not trigger a response from a receiver circuit. If they do, then the signals "connect" the two circuits together even if there is no physical linkage between them. A popular saying goes "everything is connected". But that saying should be qualified as "connected directly or indirectly via feedback signals and/or resonance of movements".
Feedbacks can also mean processes that take place in circuit loops. Looped circuits have circular causality of trigger and response. The response of any component to a trigger signal in the loop will circle back to itself at a later time, in the form of a new trigger from the reaction of another component. One type of this feedback loop is negative feedback. James Watt (1736-1819) utilized negative feedback in his design of steam engine. Alfred Russel Wallace (1823-1913) alluded to it in his theory of evolution. The concept of negative feedbacks changed the course of scientific knowledge.
Negative feedback made the output of steam engine controllable. The ability to regulate machine outputs under different load conditions was a game changer. It ushered in the Industrial Revolution. Then World War II saw Norbert Wiener (1894-1964) and his theory of cybernetics. This theory provided mathematical models for negative feedback control. One cybernetic model allows a thermostat to control the temperature of a room with varying conditions. Another cybernetic model enables a radar-guided missile system to track and hit the target, regardless of the target's location or movement. Today, feedback processes are found in many branches of science that involve interactive systems, including the nervous systems that host and interact via IFPs and neurochemicals.
Feedbacks Terminology - feedback, feedforward, reentrant signals.
-- picture of feedback, feedforward, reentrant signals
Sometimes the term feedback is used interchangeably with the term feedforward. A sender circuit transmits feedforward signals to one or more receiver circuits, and a receiver circuit senses feedback signals broadcasted from one or more sender circuits. The usage depends on the perspective of signal travel direction.
But feedback has connotations that feedforward lacks. First, feedback circuits are connected circularly while feedforward circuits may not be so. Second, the receiver circuit of feedback signals is an active system whose internal energy supply enables it to respond to the signals actively instead of passively. Receiver circuits of feedward signals may react passively to the signals.
A passive response to an input can be likened to a sitting billiard ball being hit by a moving billiard ball. This sitting ball will be pushed away by the moving ball, an outcome predictable in terms of physical motion and energy budget. An active response can be likened to a man being pushed by another man. In addition to being moved somewhat by the impact of the push, the man may also respond energetically and unpredictably: cursing or punching back or doing something else. The internal energy supply enables the man being pushed to react more unpredictably than the law of physics can reveal.
In the course of evolution, lifeforms emerged from movements of inanimate elements. A critical point of such emergence probably has to do with the appearance of internal energy structures. Somehow, structures as a store of usable energy got attached to some other structures that can utilize that energy, and they became an active system together. From that, feedback interactions began with active systems. It may not be too far off the mark that simple active systems that respond to stimuli chemically will aggregate into groups of active systems that respond to stimuli biologically.
There is another name for feedback signals: reentrant signalling. This is a term used by Gerald Edelman (1929-2014) in his Theory of Neuronal Group Selection (TNGS). TNGS is a theory that also attempts to explain aspects of mental consciousness in terms of signalling activities of neuronal circuits (neuronal groups). Edelman specifies that reentrant signalling is not feedback signalling, at least not in the sense of negative feedback control. It is about emergent mental phenomena arising from recursive interactions of neuronal groups. However, that recursive interactions of neuronal groups are exactly like feedback processes. And resonant responses of IFPs in neuronal circuits also have a role in this.
Feedbacks Circuits - sensor, governor, object, feedback connections
-- Diagrams of feedbacks of one system and between two systems. Each system has a sensor and a governor circuit. -----
Feedbacks take place in looped circuits. A feedback circuit has a sensor unit, followed by a governor unit and then an object unit (a load or a responding system). Signals in feedback circuits travel from the sensor to the governor to the object and back to the sensor unit. This output-to-input feedback loop can take place in a single circuit (systemic feedback), two circuits (mutual feedback), or more (complex feedback).
The sensor unit gets an input from the response of the object unit. It compares this input to a threshold value or reference (adjustable). The difference of the comparison is fed to the governor unit, which acts according to that difference, and that action is received by the object unit. The response of the object unit to the governor's action then becomes the input fed back the sensor. This arrangement makes the three components respond to each other circularly via the feedback signals going around the loop.
The circular causality of the circuit components can lead to complex outcomes. But that can be simplified to a simple relationship: the ratio of successive sensor outputs (difference of an input to a reference). When a second output is equal to or greater than the first output, then it is positive feedback. If the sensory outputs decrease progressively, then it is negative feedback. These two types of feedbacks can account for many natural processes, in both mental and physical realms.
Feedbacks Dynamics - 1) negative feedback, 2) positive feedback
1) Negative feedback
(pic) cruise control. thermostat. body temperature homeostasis (hypothalamus.)
Negative feedback can be exemplified by automobile's cruise control system. The cruise control system helps a car move at a constant speed by automatically adjusting the fuel supply or brake application. This control is needed because a car's speed can change even under a same rate of fuel feed. It can be affected by the road conditions like uphill or downhill, or the winds.
To maintain the speed constant for a car, the cruise control uses negative feedback to reduce speed differences detected by its sensor unit. The sensor unit has one input that reads the speed of the car (from the turning of wheels), and another input that reads the reference speed (cruise speed) set by control buttons. The sensor provides the difference of the two inputs (deviation/error from the reference speed) and feeds that information to the governor circuit at regular intervals.
The governor unit computes and acts on the seneor information. It calculates from the difference information how much fuel or brake force is needed to apply to the object unit (the car wheels) in order to reduce the deviation from the set speed, and enacts it repeatedly till the difference reaches a minimum. In other words, when the car is moving above the cruise speed, the govenor will apply a calculated brake force or fuel reduction to slow down the car. When the car is moving below the curise speed, the governor will apply more fuel to make the car go faster. It is called negative feedback (control) because the system works together to negate deviations of a parameter from some reference value.
Negative feedback can also be called reduction feedback, convergence feedback, or homeostasis. It stabilises a certain parameter in a system. All self-regulating systems can have negative feedback circuits. Examples are the constant body temperature of warm-blooded animals, smooth movements of robotic parts, or stable population of an ecosystem. In machines, the governor unit of the feedback circuit has to be designed and made. But in living ecosystems, there is no designated governor unit, at least not physically. It is neither an entity nor a dominant figure. The governor is information immanent in the interactions among the constituents of the living ecosystem. To put it figuratively, it is the invisible "Natural Selector" that pulls the strings behind the scene.
2) Positive feedback
-- pic of popularity rating (greater viewing from greater recommendation).
Positive feedback can be exemplified by the process of mutual escalation. YouTube videos going viral is an example. Some sensor algorithm keeps track of how many times a video is watched. Comparing the number of views to some reference numbers, another algorithm (governor) calculates how to recommend the video to the public (object unit). The public responds to the recommendation by watching or not watching the video. If the public's viewership goes higher (detected by the sensor algorithm), the governor algorithm will issue more recommendation of this video to other viewers, resulting in yet greater number of viewings. This "going viral" is a process of positive feedback.
The popularity of the video leads to promotion of it. And promotion of the video leads to greater popularity of it. This is symmetric schismogenesis, a term coined by Gregory Bateson. A stronger tie between popular video makers and the YouTube company emerges as they both benefit from the popularity. They form a symbiotic relationship that leads them to co-dependence. A co-dependent relationship consequent to positive feedback interactions can happen in complementary schismogenesis also. Bateson specifies that as patterns of opposites, like dominance-submissiveness, that have strong bonding between them.
-- pic of argument/fight
Argument between two people is also an example of positive feedback. This happens in the story of Joy of Fish. The argument heats up as each person detects errors (deviations from private reference) in the other person's statements and tries to correct that. This is symmetric schismogenesis. Schism = division, genesis = beginning. The two people, say C and H, have their C-reference and H-reference respectively. Person C makes a C-statement. Person H compares that C-statement with his H-reference and makes an H-statement to correct that C-statement. Vice versa, person C compares the H-statement to his C-reference and make another C-statement to correct that H-statement, and so on and so forth.
Positive feedback is amplification feedback. It leads to greater digergence of subsystems but possibly also co-dependence of them. The escalation of differences can progress rapidly from the stage of amplification to the stage of saturation and then possibly to a stage of irreversible breaking apart. That breaking apart is typically where a change is observed. On the other hand, negative feedbacks avert change. They prevent escalation from happening. So the process of positive feedback can also be called divergence or amplification feedback, and negative feedback can be called convergence or reduction feedback.
NEXT
Associative memory can be triggered to replay by feedback signals among active systems. This article shows some examples of associations that reflect recall of memories associatively. It also provides an overview on feedback signals and feedback processes. Memory replay in active systems require structures and interaction dynamics that evolve overtime. That brings up the subject of evolution, and the role of feedback interactions in it. The next article will provide an overview of evolution and its developmental paths to structures that exhibit memory dynamics.
