Wild to Civilized

Flocking:
Everybody Together

The interpersonal movements that lead to flock, herd, and crowd formations.

From small nomadic packs 

in the African wilderness . . .

. . . to megacities linked in

a global industiral civilization

Flocking

Flocking is when certain species of  animals recognize their own species members, but not particular individuals within their species. Sheep are a good example, and we often use sheep disparagingly against people who just "follow the herd." In terms of movement, flocking is when the species members move within a large-sized group of fellow members. In their individual-to-individual movements, they remain head to tail, side by side, but avoid any head-to-head movements.

A dramatic sight to see when walking or driving outdoors is a large flock of birds flying in formation – as if the whole flock were one single animal. I am always awed and amazed as I watch a flock of birds fly first in one direction, then curve around and fly in the opposite direction – repeating these movements several times before suddenly taking off in yet another direction. Careful observation reveals no one “leader” bird directing the others. I have watched a flock fly back & forth & I could see how individual birds in the flock continually shifted their positions in relation to each other – yet the whole formation maintained the same overall shape as it moved through the sky. How do so many individual birds all fly in the same direction without crashing into each other or going off in all directions?

 

My neighbor’s bird feeder gives us the answer. Besides the continuous song of tweets and twitters, birds are seated all along the branches of nearby shrubs.  They are regularly seated side by side, all facing in the same direction? Conveniently, they never sit facing each other.

 

The secret of how so many birds fly in formation with no leader – their flock resembling a single gigantic creature is seemingly simple: these animals AVOID another’s front and APPROACH another’s back. You can say that flocking animals are repulsed by (or afraid of) their fellows’ faces and so avoid those faces. And you can also say that they are attracted to (or like) their fellows’ backs. This particular combination of likes and dislikes ends up with flocking animals following after each other. These animals end up in large herds roaming their habitats in search of food.

Figure FvF below shows one bird approaching two other birds head-on (i). When they meet, they all turn away from each other (ii). When the black bird encounters another two birds, they all end up following each other head to tail.

 

Figure FL below illustrates the spatial arrangements that result when several individuals come together who flock in response to each other.

(1) Two individuals approach head-on, each seeing the other’s face. Repulsed by those faces, each turns away from the other– thereby noticing the other’s back. The sight of a back reverses the direction of their movement. Now attracted to the other’s back, they each approach that back. If nothing else attracts them away, our tiny four legged animals would spend eternity circling round each other.

 

(2) A third tiny four legged animal (C) approaching our pair is repelled by their faces and attracted by their backs. “C” turns away from his fellows’ faces – and thereby notices their backs. “C” joins the circle. The lines connecting the three individuals in the fourth picture above represent how the forces and resulting movements maintain the circle’s shape. Dotted lines connecting each individual’s face represent the repulsive force, the avoidance that keeps the animals’ heads apart; solid lines connecting each individual’s back represent the attractive force, the approach to each individual’s back which keeps the animals following after each other.[1]

 

Figure FLA at the top shows flocking animals attracted by food but repelled by each other’s faces.

As each moves away from the face, he or she catches sight of the other’s back so turns to follow that back which is in the same direction as the succulent grass upon which his buddy is feeding. Now they are in the comfortable side-by-side position.  They graze peacefully together.

 

The second line of animals below represent two youngish male dogs who are peaceful strangers. When they first meet, they respond to each other with flocking – approach the tail; avoid the head. One dog moves toward the tree with the second dog following. The first dog marks the tree as his territory; the second dog follows and does the same. Then both dogs go off, one still following the other. Dogs, however, are aggressive animals who are capable of fighting as well as flocking.

 

As Konrad Lorenz described the flock:

 

"The concept of the flock is determined by the fact that individuals of a species react to each other by attraction and are held together by behavior patterns which one or more individuals elicit in the others. Thus it is typical of flock formation when many individuals travel in close formation in the same direction." [2]        

Flocking individuals whose motivation is exclusively social – in other words, responding only to members of their own species and not distracted by any other objects in their environment – form circles in which each individual moves in the same clockwise or counterclockwise direction. A circular pattern is balanced and stable because each flocking individual is approaching the rear of the individual in front of him or her and avoiding the heads of all the others.

 

Let’s take a closer look at Figure FL:

Its drawings are simple stick figures representing dogs, which we will often use in our illustrations of movement. As two individuals a and b approach head-on (1), sight of a’s frontquarters stimulates b to turn away and vice versa. While turning away, each sees the other’s rearquarters (2), which stimulates each one to follow the other. The result is a circular pattern of movement. When a third individual c approaches these two, it is attracted to individual a’s rearquarters and repulsed by individual b’s frontquarters. As a result, c turns towards a and away from b. Meanwhile, b is repulsed by c’s frontquarters and turns away until he sees c’s rearquarters, which attracts him. The result is once again a circular pattern of movement.

 

In real life, however, behavior is rarely motivated exclusively by sociability. Other objects in the environment – food or predators – are important to respond to, and these responses influence the movement patterns of flocking individuals. Figure FLA shows the spatial arrangements that result when two dogs (a and b) who respond with flocking to each other are also attracted by food.

As they are circling each other, a notices the food and starts to move toward it and away from b. But a’s flocking response to b causes him to hesitate and look back toward b. If b does not follow a, then when a sees b’s hindquarters and is attracted to it, a turns away from the food and returns to circling with b. If b instead does follow a, then when a looks back and sees b, the sight of b’s repulsive frontquarters stimulates a to turn away and continue moving toward the food, with b following after. When b finally sees the food, b also moves toward it. The final, stable arrangement is both a and b eating the food they are attracted to and standing side by side with each other, avoiding a face-to-face position. Their motivation to be together and to eat food is balanced, and they are both facing in the same direction. Cows are flocking animals who typically stand close to each other and graze only in one part of a large field all stand facing in the same direction. If they stand further apart from each other because they are more attracted to the food than to each other, they may stand at different angles to each other. Their flocking response to each other still shows by their remaining together in the same small part of a large field.

 

Flocking creatures discriminate only between different species, not between individuals of their own species. “(E)very individual is just as content with any one fellow member of the species as with any other.”[2] Rather than distinguishing between individual members of their own species, flocking individuals distinguish only their own species’ fronts from their backs. The direction of their social response – approach or avoidance – depends on whether they see a front or a back, not upon which front or back they see.

        

The basis for this social reaction is imprinting, a response laid down during infancy in many species. Imprinting is the relatively short period in a young creature’s life when it learns to recognize and respond to members of its own species. During that critical period the infant responds to the first appropriately-sized moving object it sees – usually its mother -- with an approach response. The infant sees just enough of that object’s identifying characteristics so that, from then on, only objects of that general class bring out the individual’s social responses. At a certain stage human infants begin to recognize and respond to other individual humans in general. Only later will they learn to recognize their mother and father as distinct from each other and distinct from all other human beings. Konrad Lorenz, the German ethologist who went a long way towards identifying the various social responses among animals, was able to get baby goslings to imprint on him rather than their mother. He intruded into the normal development of geese by substituting himself for their mother. And it worked. The baby goslings followed him everywhere he went. And when they grew up, they wanted to mate with other humans, not with each other.

           

Flocking individuals never make it to recognizing “mother,” “father” or any other particular individual of its own species. All are the same. They all look alike to each other and they all respond to each other with approach to the rear. As a result, very large numbers of flocking individuals may aggregate together. Whether there are five, 15 or 50 of them, animals who respond to one another with flocking all bunch tightly together rather than dispersing themselves evenly across all the space available to them. On one of our hiking adventures, for example, we observed 15 cows in a fenced field about a quarter mile long and a city block wide all clustered together within an area no more than 40 feet in diameter.

 

The value of flocking

           

The flock formation, which is commonly found among herbivores, is a protection against predators. To hunt, the carnivorous predator must distinguish its prey as an object from the prey’s surrounding background. To do so, the predator avoids hunting amidst large herds of animals, searching instead for the isolated stray – the young, the elderly, or the sick.                                                                                                                                                           

Large aggregations make it increasingly difficult to distinguish one particular individual to go after, which foils the predator and saves the flock. Lorenz describes this “weakness” in the perceptual abilities of predators:

"…[I]t seems scarcely believable that a single, small, but widespread weakness in predators could have wrought such far-reaching consequences in the behavior of their prey. This weakness lies in the fact that many, perhaps all, predators which pursue a single prey are incapable of concentrating on one target if, at the same time, many others are crossing its field of vision. Just try, yourself, to catch a single specimen from out of a cage full of birds…[Y]ou will be astonished to find how hard you have to concentrate on a specific bird in order to catch one at all. You will also notice how incredibly difficult it is to concentrate on a certain bird and not allow yourself to be diverted by an apparently easier target. The bird that seems easier to catch is almost never caught, because you have not been following its previous movements, you cannot predict its next movements…The predatory fish, like the radar-guided missile, lacks the ability to blind itself voluntarily to one objective in order to concentrate on the other."[3]

 

Our greyhound Rishi demonstrated this trait of predators. Walking with Lenore in a crowd of humans, our greyhound Rishi, would lose Lenore in the crowd. He would begin to search around, moving towards females of Lenore’s size and shape and, when close enough to see or smell more details, turning away. At these times Rishi would respond to Lenore’s loud call – “ReeeeeeeeSheeeeeeee” -- with great energy, bounding over and greeting her with joy and relief. In this situation, Rishi needed more cues than just the visual.

 

The anonymity of flocking

The responses that flocking individuals have to each other – approach the tail and avoid the head – ensures their togetherness. But togetherness is not the only distinctive feature of flocks. The positions of individuals within the flock are constantly shifting. No two particular individuals stick together for very long in the flock. If they meet face to face, they turn away from each other and towards others. If they meet a tail, they follow that tail until they see another face. The shifting is continuous. There is an almost equal chance of any two individuals in the flock being adjacent to each other as any two other individuals. This is exactly the opposite of what happens to aggressive individuals. Instead of the random shuffling around of the flock, aggressive individuals maintain fixed positions vis-a-vis one another.

 

On one of our walks, Lenore saw a flock of about fifteen pigeons. She wanted to see how hard it would be to track one particular individual in the flock. It turned out unexpectedly difficult. Lenore managed about 35 to 45 seconds of concentration. Each time her pigeon came face to face with two or three of his flock mates, he turned away, tracing a zig-zag course through the flock. He created a small wake behind him as his flock mates also turned to stand parallel to him. But none followed him. As soon as he moved more than a bird’s length away from them, other closer birds exerted stronger attractive or repulsive energy. And once Lenore lifted her eyes from him for half a second, she was unable to identify him when she looked back. All one can predict, then, is that a whole collection of flocking individuals will remain together. But the positions of specific individuals in relation to each other are not fixed.

           

The flocking relationship is the simplest of all social relationships among vertebrates, but the visual pattern formed by their movements is, paradoxically, one of the most complex. Among flocking animals like sparrows, their small size enables them to move very rapidly. The continuous shifting of individuals creates a quality reminiscent of light bouncing back and forth in a seemingly random pattern as it is reflected from a many-faceted jewel. The slow and ponderous movements of larger flocking animals like cows, however, create the impression of a group of drunkards.

 

On a warm day we observed a collection of 15 cows huddled together so closely that they were touching each other. So strong was their motivation to be close that some of the cows around the edges of the herd periodically mounted the cow in front of them. A slow but steady stream of movement was created as each mounted cow moved away and then came back around to shove herself in between two closely huddled cows, pushing them apart if there was room or mounting one of them if there was  not room. So clumsy did these animals appear that one would think they were blind – except for one detail. None of them stood face to face. They either huddled side by side or formed a line in which all individuals faced in the same direction.

           

Because flocking individuals discriminate only between different species and not between different individuals in their own species, their flocking response may be described as universalistic rather than particularistic. A particularistic response means the individual is able to detect and respond to a unique combination of traits belonging to a single member of its species. “Joe has a crooked nose, freckles, red hair etc. Amy has a long face, light skin, black hair etc.” On the other hand, a universalistic response means the individual detects and responds to just a few traits shared by every member of its species. “Hi, mate; I see you have a red spot on your beak like all the rest of us here.” “[E]very individual is just as content with any one fellow member of the species as with any other.”[4]

           

Personal leadership is non-existent within the anonymous flock. An individual in the flock spies an attractive object in the environment – say, food. Immediately it moves towards that object. But if none of his mates follow after him, he becomes isolated from the flock. Immediately, he stops his approach to the food and turns back to the flock. If the individual sees more heads than tails when it looks back, it will turn away from the flock and toward the food becoming, for the moment, a “leader.” But if the individual, when turning back, sees more tails than heads, it will be pulled back to the flock and away from the food. The direction the flock moves in thus depends purely upon how many individuals in the flock respond to an outside stimulus, not who responds to it. Here is how Lorenz describes it:

 

The purely quantitative and, in a sense, democratic action of this process…means that a school of fish is the less resolute the more individuals it contains and the stronger its herd instinct is. A fish which begins, for any reason, to swim in a certain direction cannot avoid leaving the school and thus finding itself in an isolated position. Here it falls under the influence of all those stimuli calculated to draw it back into the school. The more fish there are swimming in the same direction, as the result of some exogenous stimulus, the more likely they are to draw the school with them; the bigger the school and its consequent counterattraction, the less far its members will swim before they return to the school, drawn as by a magnet. A big school of small and closely herded fish thus presents a lamentable picture of indecision. Again and again a small current of enterprising single fish pushes its way forward like the pseudopodium of an amoeba. The longer such pseudopods become, the thinner they grow, and the stronger becomes their longitudinal tension. Generally the whole advance ends in precipitate flight back to the heart of the school. Watching these indecisive actions, one almost begins to lose faith in democracy [and to see the advantage of authoritarian politics – OMIT].[5]

 

Flocking among humans

           

Human beings are capable of all three interpersonal responses – flocking, fighting and friendship. Flocking in particular is common in urban situations. Cities themselves are a kind of huge flock. Within cities are numerous smaller instances of flocking: people in audiences, people walking along crowded streets, people standing in lines, students in classrooms, cars on roads and highways – to mention a few. All the characteristics of non-human flocks occur in these human situations. The relationships between particular individuals are brief as the individuals in the human flock move promiscuously from one to another to another. People in crowded streets and cars on highways move almost continuously.  But even if audiences and students in classrooms are generally immobile, it is only for relatively short periods of time – compared to, say, a marital relationship – and then the audiences and the students disperse and reassemble into new flocks with different individuals.

           

The relationships in human flocks are anonymous, or nearly so, and universalistic. Most people in audiences or classrooms or crowded streets don’t know each other as friends do. And what is relevant about one person to another in a human flock is the most basic, universally-shared characteristics. In a classroom, the status of student is shared by all. On a road or highway, being a car is all that matters to everyone. In a line at a bank or supermarket, everyone is a person-in-the-line and nothing more. The particularistic features of persons – names, clothes, family roles, occupations, habits and preferences – are irrelevant and ignored in flocking situations. Roles of individuals are standardized. A check-out person in a grocery store is there for one purpose common to all check-out persons. People rely on bank tellers to do exactly the same transactions regardless of which teller they encounter. Many, many roles are standardized in human flocks: professor, student, police officer, news reporter, gas station attendant, auto mechanic, salesman, etc. A flocking relationship does not always have to occur in one sort of crowd or another. A salesman or auto mechanic may deal with one customer at a time, but the relationship is brief and universalistic, and the roles are standardized.

           

The relationships in human flocks (like all flocks) are also promiscuous – not sexually so much as socially. One individual is as good as another to interact with. And individuals move from one to another and another indefinitely. From time to time, one individual will stop to interact longer with another particular individual, a sign of other interpersonal responses showing forth. But in general relationships are brief, universalistic, anonymous and promiscuous.

Equality and flocking

           

Modern industrial society values equality. Gone are the days of monarchy and aristocracy. Modern society comes with a leveling of statuses. Ever since the Enlightenment, the goal in modern society has been to make all individuals socially and politically indistinguishable. Democracy champions the right of every individual to vote and to aspire without barriers to any position in society.

           

Perhaps ironically, flocking is the ultimate in equality. No one is dominant in the flock. Everyone decides and acts by a consensus of the group.

           

Many features in modern society show a tendency to create a more flock-like structure compared to past societies. For example, the high divorce rate and the prevalence of serial monogamy both involve the shortening of the marital relationship and the quickening of movement of men and women from one mate to another. Similarly, schools segregate the younger from the older, effectively equalizing statuses among the young as a group and among the old as a group. Schools go yet further with their very fine age-grading, dividing everyone into groups based on equal age within each group. Among each age group, no one is dominant, ensuring that students have no experience with each other except as equals – equally weak. The division of the school day into hour-long sessions from junior high school onward ensures that students rotate and reorganize themselves into ever briefer relationships, approximating the perfect flock.

           

In the same vein, modern society has become highly mobile, with households moving to new residences and new locations on an average of every seven years (?), resulting in shorter relationships with neighbors and changing jobs on an average of once every ____________ years, resulting in shorter relationships with co-workers.

           

Finally, we must remark on the fads and fashions of modern society, which come and go with a high rapidity, everyone watching where others move and moving after them. And occasionally there is mob behavior, where strangers in densely packed crowds respond with short flashes of identical intense activity, only to gradually disband and disappear back into the anonymous society.

 

Approach and avoidance

 

The basis of all behavior in social animals, no matter how complex its final expression, is simply movement towards or away from particular objects. An individual approaches one individual of the same species but avoids another individual. An individual approaches its prey and flees from its predator.

           

For these movements to take place, internal energy is generated which propels the individual to move in a definite direction – towards or away from a particular environmental object. When an animal is hungry, it searches for food, locates it, and moves toward it. When an animal feels lonely, it searches for a partner, locates it, and moves toward it. The presence of the food or the partner in the individual’s environment combines with the individual’s internal state of arousal to produce the behavior: movement towards food or a partner.

           

Movement away from an object is similar. A frightening external stimulus triggers the individual to move away from it. In other words, flee.

           

What we are concerned with in this work are the patterns in which individuals move in relation to members of their own species – their conspecifics, which means "with species," as is said among scientists. Let us see how this works out in flocking.

 

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[1] There is an unanswered question here which requires more data to answer. At exactly what point on the animal’s “side” does the perceptual boundary between front and back fall. The drawings above are drawn as if only the face is front and only the tail is back. In real life we do not believe this is true. Indeed, we have some evidence to that effect. My son, an electrical engineer, developed a simple computer program in which arrows represented animals, the point of the arrow being the front and the end of the line being the back. The arrows were programmed to avoid each other’s fronts and approach each other’s backs. And that is exactly what they did. But, rather than forming a circle, they all moved in one straight single file line. The next step in this demonstration might be experimenting with the location of the boundary on the animal’s side that separates front from back.

 

[1] Konrad Lorenz, "On Aggression," 1967, fifth printing, p. 141.

[2] Konrad Lorenz, "On Aggression," p. 133.

[3] Lorenz, "On Aggression," pp. 136-137.

[4] Lorenz, "On Aggression," p. 133.

[5] Lorenz, "On Aggression," p. 139.

Questions or comments:  schlomings@gmail.com.

 
 
 
 
 
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