Obesity

Obesity preview image

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Default-person Cal Newlon (Author)

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breed [females female]
breed [males male]
breed [dieticians dietician]


turtles-own
[
  male_height_squared   ; how tall a male person is in metres squared for calculation of BMI
  female_height_squared ; how tall a female person is in metres squared for calculation of BMI
  male_weight    ; the weight of a male person in kg
  female_weight   ; the weight of a female person in kg
  BMI_male    ; the body mass index of a male to indicate underweight, healthy, overweight or obese
  BMI_female  ; the body mass index of a female to indicate underweight, healthy, overweight or obese
  pride-shame
  gratification-remorse
  health-consciousness
  male_pride-shame
  female_pride-shame
  male_economic_class ;males are placed in an intial economic class
  female_economic_class  ;females are placed in an intial economic class
  male_attitude   ;individual attitude towards health(exercise)
  female_attitude  ;individual attitude towards health(exercise)
  male_pbc ;male perceived behavioral control
  female_pbc ;female perceived behavioral control
  male_vision ;how far a male sees
  female_vision ;how far a female sees
  male_total_seen  ;total number of males seen in turtle's vision
  female_total_seen ;total number of females seen in turtle's vision
  male_healthy_seen  ;indicates if a healthy male is seen
  female_healthy_seen  ;indicates if a healthy female is seen
  male_subjective_norm ;indicates a males SN value
  female_subjective_norm ;indicates a females SN value
  male_intention ;indicates a males total likelihood to engage in healthy behavior
  female_intention ;indicates a females total likelihood to engage in healthy behavior
  newmale_weight ;calculation of new male weight after each tick
  newfemale_weight ;calculation of new female weight after each tick
  my-group ; turtle group
  friends_total
  friends_healthy
  friends_influence
  male_emotions
  female_emotions
  just-exercised

]

to setup
  clear-all
  ;;set global variables to appropriate values
  setup-patches
  setup-turtles
  assign-turtle-groups
  reset-ticks
end 

to setup-patches
  ask patches [ set pcolor pink ]  ;set patches to color pink
end 

to go
   move-turtles ;moving around
   exercise-turtles ;exercise is used to mean "engage in healthy behavior (i.e. eat healthily and exercise)
   update-turtles ;give them their new weight all at once
   recolor-turtles ;recalculate BMI and assign new categories


   tick
end 

to move-turtles  ;this allows turtles to move in a random direction
  ask turtles [
    ifelse (random 100 <  movement) ;controls for movement in society with slider
    [
     right random 360
      forward 1]
    [forward 0]
     ]
end 

to setup-turtles
    set-default-shape turtles "person"
    create-males number / 2 [ setxy random-xcor random-ycor
    set male_height_squared random-normal 3.103219 .2077     ;setting initial male height squared to calculate BMI
    set male_weight  random-normal (72.1212 * starting-weight) 4.2335  ;initializing male's random weight
    set male_pride-shame max (list(min (list (random-normal .4 .2)1) )0)  ;initializing male's random body image
    set male_economic_class min( list (random-exponential (1 / 2)) 1)   ;initializing male'seconomic class
    set male_vision vision
    set just-exercised 0
    ifelse (random-float 100 < health-awareness)
      [set health-consciousness 1]
      [set health-consciousness 0]
    ]   ; initializing male vision
    create-females number / 2 [ setxy random-xcor random-ycor
    set female_height_squared random-normal 2.757414 0.1957    ;initializing female height squared to calculate BMI
    set female_weight  random-normal (61.4618 * starting-weight) 4.0067   ;initializing female's random weight
    set female_pride-shame max (list(min (list (random-normal .4 .2)1) )0)  ;initializing female's random body image
    set female_economic_class min( list (random-exponential (1 / 2)) 1)   ;initializing female's random economic class
    set female_vision vision
    ifelse (random-float 100 < health-awareness)
      [set health-consciousness 1]
      [set health-consciousness 0] ]  ;initializing female vision
    set-default-shape turtles "person"
    create-dieticians dietician-number [setxy random-xcor random-ycor
    set color white
    set just-exercised 0
  ]
end 

to exercise-turtles
  ask males
  [set male_attitude (male_pride-shame - 2 * gratification-remorse) ;for now, attitude is just related to body image and does not change over time
    set male_pbc .4 * (max (list(min (list (random-normal male_economic_class .4) 1)) 0)) + random-float .7 ;behavioral control cares about economic class, but also has some random noise
    ask turtles in-radius male_vision ;how many total turtles are seen
    [set male_total_seen count males in-radius male_vision + count females in-radius male_vision
      set male_healthy_seen (count males in-radius male_vision with [BMI_male < 25]) + (count females in-radius male_vision with [BMI_female < 25])] ;how many healthy turtles are seen
    ask turtles with [my-group = [my-group] of myself]  ;how many total turtles are seen
    [set friends_total (count males with [my-group = [my-group] of myself] + count females with [my-group = [my-group] of myself])
      set friends_healthy (count males with [BMI_male < 25 and my-group = [my-group] of myself]) + (count females with [BMI_female < 25 and my-group = [my-group] of myself])]
    set friends_influence (friends_healthy / friends_total)
    set male_subjective_norm ((0.5 + (min (list male_total_seen 20))* (.05) *((male_healthy_seen / male_total_seen) - 0.5)) + friends_influence)

    set male_intention min (list (.4718 * male_attitude + .2554 * male_subjective_norm + .2728 * male_pbc) 1) ;assigns weights calculated from Godin review
    ifelse (random-float 1 < male_intention) ;likelihood to exercise doesn't guarantee exercise - random float allows for disparity between intention and behavior
    [
      ifelse (BMI_male > (20))
      [set newmale_weight (male_weight - random-float .1)
      set just-exercised 1] ;people above BMI of 20 will continue to lose weight when engaging in healthy behavior
      [set newmale_weight (male_weight + random-float .01 - random-float .01)
      set just-exercised 1] ;people at or below BMI of 20 will fluctuate around their current weight
    ifelse (health-consciousness = 1)
        [set gratification-remorse .5]
        [set gratification-remorse .1]
    ]
    [
      ifelse(random-float 1 < .75) ;possible either to stay the same weight or gain weight when not healthy
      [set newmale_weight (male_weight +  random-float 0.1)
      set just-exercised 0] ;weight gain is random between 0 and 0.1
      [set newmale_weight (male_weight)
      set just-exercised 0] ;possible to remain same weight
        ifelse (health-consciousness = 1)
        [set gratification-remorse -.5]
      [set gratification-remorse .5]]


    ifelse (random-float 1 < .01)
       [set health-consciousness (1 - health-consciousness)]
    [set health-consciousness health-consciousness]
  ifelse (count dieticians in-radius male_vision > 0)
    [set health-consciousness 1]
    [set health-consciousness health-consciousness]]
  ask females ;female procedure is identical to males above
  [set female_attitude (female_pride-shame - 2 * gratification-remorse)
    set female_pbc .4 * (max (list(min (list (random-normal female_economic_class .4) 1)) 0)) + random-float .7
    ask turtles in-radius female_vision
    [set female_total_seen count males in-radius female_vision + count females in-radius female_vision
      set female_healthy_seen (count males in-radius female_vision with [BMI_male < 25]) + (count females in-radius female_vision with [BMI_female < 25])]
     ask turtles with [my-group = [my-group] of myself]  ;how many total turtles are seen
    [set friends_total (count males with [my-group = [my-group] of myself] + count females with [my-group = [my-group] of myself])
      set friends_healthy (count males with [BMI_male < 25 and my-group = [my-group] of myself]) + (count females with [BMI_female < 25 and my-group = [my-group] of myself])]
    set friends_influence (friends_healthy / friends_total)
    set female_subjective_norm ((0.5 + (min (list female_total_seen 20))* (.05) *((female_healthy_seen / female_total_seen) - 0.5)) + friends_influence)

    set female_intention min (list (.4718 * female_attitude + .2554 * female_subjective_norm + .27728 * female_pbc) 1)
    ifelse (random-float 1 < female_intention)
    [
      ifelse (BMI_female > (20))
      [set newfemale_weight (female_weight - random-float .1)
      set just-exercised 1]
      [set newfemale_weight (female_weight + random-float .01 - random-float .01)
      set just-exercised 1]
      ifelse (health-consciousness = 1)
        [set gratification-remorse .5]
        [set gratification-remorse .1]
    ]
    [
        ifelse(random-float 1 < .75)
      [set newfemale_weight (female_weight +  random-float 0.1)
      set just-exercised 0]
      [set newfemale_weight (female_weight)
      set just-exercised 0]
              ifelse (health-consciousness = 1)
        [set gratification-remorse -.5]
        [set gratification-remorse .5]
    ]
    ifelse (random-float 1 < .01)
        [set health-consciousness (1 - health-consciousness)]
    [set health-consciousness health-consciousness]
    ifelse (count dieticians in-radius female_vision > 0)
    [set health-consciousness 1]
   [set health-consciousness health-consciousness]
  ]
end 

to update-turtles
ask males
  [set male_weight newmale_weight ;all weights update at once
  set male_economic_class max ( list (min (list(male_economic_class + (social_mobility * .0001 * random-float 1) -  (social_mobility * .0001 * random-float 1)) 1 )) 0) ]
  ;depending on social mobility slider, people can move from one economic class to another (albeit slowly)
ask females
  [set female_weight newfemale_weight
    set female_economic_class max ( list (min (list(female_economic_class + (social_mobility * .0001 * random-float 1) -  (social_mobility * .0001 * random-float 1)) 1 )) 0) ]
end 

to recolor-turtles
  ask males
  [  set BMI_male newmale_weight / male_height_squared  ; calculation of BMI to categorize health(underweight, healthy, overweight and obese)
    ifelse  (BMI_male < 18.4)
    [set color yellow] ;; underweight individuals set yellow
   [ ifelse ( 18.4 <= BMI_male and BMI_male <= 24.9)
      [set color green] ;; healthy eating set green
     [ifelse ( 25 <= BMI_male and BMI_male <= 29.9)
        [set color blue] ;;overweight individuals set blue
        [if ( BMI_male > 30)
          [set color red]  ;;obese individuals set red
                  ]
      ]
    ]
  ]



  ask females
   [ set BMI_female newfemale_weight / female_height_squared  ; calculation of BMI to categorize health(underweight, healthy, overweight and obese)
    ifelse  (BMI_female < 18.4)
    [set color yellow] ;; underweight individuals set yellow
   [ ifelse ( 18.4 <= BMI_female and BMI_female <= 24.9)
      [set color green] ;; healthy eating set green
     [ifelse ( 25 <= BMI_female and BMI_female <= 29.9)
        [set color blue] ;;overweight individuals set blue
        [ifelse ( BMI_female > 30)
          [set color red]  ;;obese individuals set red
          []
        ]
      ]
    ]
  ]
end 



;;; this procedure randomly assigns turtles to groups based on the desired
;;; size of the groups. all the groups will have the desired size except for
;;; at most one group, which contains the remainder of the turtles. more
;;; formally, if there are n turtles, and the desired group size is k, this
;;; procedure will produce j = floor (n / k) groups of k turtles, and if
;;; n mod k > 0, it will produce one group of n mod k turtles.

to assign-turtle-groups

  ;; all turtles are initially ungrouped
  ask turtles [ set my-group -1 ]
  let unassigned turtles

  ;; start with group 0 and loop to build each group
  let group-number 0
  while [any? unassigned]
  [
    ;; place a randomly chosen set of group-size turtles into the current
    ;; group. or, if there are less than group-size turtles left, place the
    ;; rest of the turtles in the current group.
    ask n-of (min (list group-size (count unassigned))) unassigned
      [ set my-group group-number ]
    ;; consider the next group.
    set group-number group-number + 1
    ;; remove grouped turtles from the pool of turtles to assign
    set unassigned unassigned with [my-group = -1]
  ]
end 

There is only one version of this model, created almost 6 years ago by Cal Newlon.

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