Jebel Sahaba Model 1 - equal resource distribution + cows

1 collaborator

WHAT IS IT?

This model represents intergroup specific violence or primitive warfare in relation to resource competition between two prehistoric palaeolithic groups, one hunter gatherer and one (possibly) semi-settled at or around site 117 near Jebel Sahaba in Nile Valley in Sudan. It is possible that both groups could have been hunter gatherers. The site is dated to apporximatley 11000 years BP. In this model, the resources are distributed equally across the land. There is also a movable resource in this model in the form of cow shaped turtles. These represent the animal herds found in the Nile Valley.

HOW IT WORKS

(what rules the agents use to create the overall behavior of the model)

In terms of turtles, there are three types: people (black in colour), arrows (red in colour) and cows (purple in colour). People could represent a semi-sedentary group and the arrows could represent hunter gatherers.As mentioned above, both groups could have been hunter gatherers. Both groups of turtles (the people and arrows) interact with the patches (grass which represents food) and each other and also with the cows. The turtles 'eat' the grass and the cows and gain energy from that. Turtles also reproduce but only with similar type. People reproduce with people and arrows reproduce with arrows.

Grass represents the overall resources available. In this model, the resources are distributed equally across the land. There are also turtles in the shape of cows which represent herds of animals that would have been present in the Nile Valley. This is a movable resource. The turtles, arrows and people, can eat the cows for energy.

One of the very important things that the turtles do is 'eat' each other which represents killing or warfare. Turtles cannot kill the same type of turtle. People can kill arrows and vice versa. Once all of one type of turtles are killed, a message is displayed as to who won. The killing of all of one type of turtle represents the massacre or genocide that could have taken place at Jebel Sahaba where one group of people carried out repeated attacks on another group of people and they could have eventually wiped out one group completely to access their resources.

HOW TO USE IT

(how to use the model, including a description of each of the items in the Interface tab)

To use this model, the user has to press the 'set up' button followed by the 'go' button. The model goes on until one group has won. There are a range of factors that can be altered as is demonstrated by a range of slider buttons. The description of the buttons is given below:

Set-up button: Use this button to reset the model to the required conditions or factors Go button: Use this button to start the model run Initial-number-people slider: Use this slider to alter the number of people in run/experiment Initial-number-arrows: Use this slider to alter the number of arrows in the run/experiment Count people button: This button counts the number of people throughout the run/experiment. The number changes as the model runs. Count arrows button: This button counts the number of arrows throughout the run/experiment. The number changes as the model runs Show energy switch: This switch button can be turned on or off. When turned on, it shows individual energy values associated with each turtle. People-gain-from-food slider: This slider button shows the amount of energy people gain from eating food (which is the grass and the cows). It can be altered. Arrows-gain-from-food slider: This slider button shows the amount of energy arrows gain from food (which is the grass and the cows). It can be altered. Cows-gain-from-food slider: This slider button shows the amount of energy cows gain from food (which is only grass). It can be altered. Grass-regrowth-time slider: This slider button lets the user control the amount of time it takes the grass to regrow. The units are arbitrary however they are depicted as 'day' for a time reference. The time can be altered. People-reproduce slider: This slider button lets the user control the rate of reproduction for turtles shaped as people.
Arrows-reproduce slider: This slider button lets the user control the rate of reproduction for turtles shaped as arrows. Cows-reproduce: This slider button lets the user control the rate of reproduction for turtles shaped as cows. The plot/graph: This plot shows the number of turtles (people, arrows and cows) and the number of patches in real time.

THINGS TO NOTICE

(suggested things for the user to notice while running the model)

Notice how different turtle populations interact with each other and which group wins. When running an experiment on Behaviour space, notice which group wins and how many times.

Notice how the numbers of the two turtle populations and the patches (grass) fluctuate on the plot.

THINGS TO TRY

(suggested things for the user to try to do (move sliders, switches, etc.) with the model)

Try altering the values on different sliders and see what type of behaviour emerges. For example, try running the model with the value of grass regrowth time really low like 1 day and then try it with 100 days and compare the results. Does it make a difference in which population wins? How many ticks does it take for one group to kill the other one? What happens to the number of turtles for a particular population? How quickly do the numbers rise or fall?

Note: Make sure only one or at most two factors are altered in one experiment and the rest are kept constant otherwise the results might become too confusing to interpret.

EXTENDING THE MODEL

(suggested things to add or change in the Code tab to make the model more complicated, detailed, accurate, etc.)

To extend the model a range of different features can be added.

1 - Add an extra turtle in a shape of a dot to depict another group of humans living near or interacting with Jebel Sahaba site. 2 - Alternate the energies of patches to depict unequal disptribution of resources. This can be colour coded. Different coloured patches can have different energies or no energy. 3 - Change the dimensions of the world to create a bigger world.

NETLOGO FEATURES

(interesting or unusual features of NetLogo that the model uses, particularly in the Code tab; or where workarounds were needed for missing features)

This warfare model is based on a Sheep-Wolf predatory model. In the Sheep-Wolf model, wolves can eat the sheep. In this current model, both types of turtles, people and arrows, can eat each other. This means that they are killing each other. They can also eat the cows. However, the turtles in the shape of a cow cannot eat any other turtles. Moreover, since the Jebel Sahaba site seems to be a massacre site, so killing of all of one breed of turtle represents the massacre or genocide that could have taken place at Jebel Sahaba where one group of people carried out repeated attacks on another group of people and they could have eventually wiped out one group completely to access their resources.

RELATED MODELS

(models in the NetLogo Models Library and elsewhere which are of related interest)

Sheep-Wolf Predatory model in the Netlogo Model Library

CREDITS AND REFERENCES

(a reference to the model's URL on the web if it has one, as well as any other necessary credits, citations, and links)

These sources of information were directly used to construct the model or their content directly influenced the model. Individual citations and a range of other references related to warfare, violence and conflict amongst hunter gatherers and early societies are available in the main paper.

Antoine, D. M., Zazzo, A. and Friedman, R. (2013) ‘Revisiting Jebel Sahaba: new apatite radiocarbon dates for one of the Nile valley’s earliest cemeteries’, American Journal of Physical Anthropology, 150(July), pp. 68–68. doi: 10.1002/ajpa.22247.

Crevecoeur, I. et al. (2021) ‘New insights on interpersonal violence in the Late Pleistocene based on the Nile valley cemetery of Jebel Sahaba’, Nature Scientific Reports. Nature Publishing Group UK, 11(1991), pp. 1–13.

Peterson, D. and Wrangham, R. (1997) Apes and the Origins of Human Violence: Demonic Males. 2nd edn. London: Bloomsbury Publishing Plc.

Railsback, S. F. and Volker, G. (2019) Agent-Based and Indivudual-Based Modelling: A Practical Introduction. 2nd edn. Princeton and Oxford: Princeton University Press.

Wendorf, F. (1968) ‘Site 117: A Nubian final Paleolithic graveyard near Jebel Sahaba, Sudan’, in Wendorf, F. (ed.) The Prehistory of Nubia Volume 2. 1st edn. Dallas: Southern Methodist University, p. 954 to 995.

Wilensky, U. (1997). NetLogo Wolf Sheep Predation model. http://ccl.northwestern.edu/netlogo/models/WolfSheepPredation. Center for Connected Learning and Computer-Based Modeling, Northwestern University, Evanston, IL

Wilensky, U. (1999). NetLogo. http://ccl.northwestern.edu/netlogo/. Center for Connected Learning and Computer-Based Modeling, Northwestern University, Evanston, IL.

Wrangham, R. (2020) Goodness Paradox: How evolution made us both more and less violent. 2nd edn. London: Profile Books.

Comments and Questions

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Click to Run Model

globals [
  max-people
  max-arrows
]

breed [ people person ]
breed [ arrows arrow ]
breed [ cows cow ]

turtles-own [ energy ]
patches-own [ countdown ]

to setup
  clear-all


  ask patches [ set pcolor green ]



  create-people initial-number-people
  [
  set shape "person"
  set color black
  set size 1.5
  set energy random (2 * people-gain-from-food)
  setxy random-xcor random-ycor
  ]

  create-arrows initial-number-arrows
  [
    set shape "arrow"
    set color red
    set size 1.5
    set energy random (2 * arrows-gain-from-food)
    setxy random-xcor random-ycor
  ]

  create-cows initial-number-cows

 [
    set shape "cow"
    set color violet
    set size 1.5
    set energy random (2 * cows-gain-from-food)
    setxy random-xcor random-ycor
  ]
  reset-ticks
end 

to go

  if not any? turtles [ stop ]

  if not any? arrows and count people > max-people [ user-message "Agriculturalists won" stop ]
  if not any? people and count arrows > max-arrows [ user-message "Hunter gatherers won" stop ]

  ask people [
    move
    set energy energy - 1
      eat-grass
      eat-cows
      eat-arrows
      death
      reproduce-people
  ]


  ask arrows [
    move
    set energy energy - 1
    eat-grass
    eat-cows
    eat-people
    death
    reproduce-arrows
  ]

 ask cows [
    move
    set energy energy - 1
    eat-grass
    death
    reproduce-cows
  ]

 ask patches [ grow-grass ]

  tick
end 

to move
  rt random 50
  left random 50
  fd 1
end 

to eat-grass
  if pcolor = green [
    set pcolor brown
    set energy energy + people-gain-from-food
    set energy energy + arrows-gain-from-food
    set energy energy + cows-gain-from-food
  ]


  ifelse show-energy?
  [ set label energy ]
  [set label "" ]
end 

to reproduce-people  ;
  if random-float 100 < people-reproduce [
    set energy (energy / 2)
    hatch 1 [ rt random-float 360 fd 1 ]
  ]
end 

to reproduce-arrows
  if random-float 100 < arrows-reproduce [
    set energy (energy / 2)
    hatch 1 [ rt random-float 360 fd 1 ]
  ]
end 

to reproduce-cows
  if random-float 100 < cows-reproduce [
    set energy (energy / 2 )
    hatch 1 [ rt random-float 360 fd 1 ]
  ]
end 

to eat-people
  let prey one-of people-here
  if prey != nobody  [
    ask prey [ die ]
    set energy energy + arrows-gain-from-food
  ]
end 

to eat-arrows
  let prey one-of arrows-here
  if prey != nobody [
    ask prey [ die ]
    set energy energy + people-gain-from-food
  ]
end 

to eat-cows
  let prey one-of cows-here
  if prey != nobody [
    ask prey [ die ]
    set energy energy + people-gain-from-food
    set energy energy + arrows-gain-from-food
  ]
end 

to death
  if energy < 0 [ die ]
end 

to grow-grass
  if pcolor = brown [
    ifelse countdown <= 0
      [ set pcolor green
        set countdown grass-regrowth-time ]
      [ set countdown countdown - 1 ]
  ]
end

There is only one version of this model, created about 4 years ago by Durr-e-Maknoon Tariq.

Attached files

File	Type	Description	Last updated
Jebel Sahaba Model 1 - equal resource distribution + cows.png	preview	Preview for 'Jebel Sahaba Model 1 - equal resource distribution + cows'	about 4 years ago, by Durr-e-Maknoon Tariq	Download

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