title: Implementing paired lines into boxplot.ggplot2
body: <p>I have a set of paired data, and I'm using ggplot2.boxplot (of the easyGgplot2 package) with added (jittered) individual data points:</p>
  
  <pre><code>ggplot2.boxplot(data=INdata,xName='condition',yName='vicarious_pain',groupName='condition',showLegend=FALSE,
    position="dodge",
    addDot=TRUE,dotSize=3,dotPosition=c("jitter", "jitter"),jitter=0.2,
    ylim=c(0,100),
    backgroundColor="white",xtitle="",ytitle="Pain intenstity",mainTitle="Pain intensity",
    brewerPalette="Paired")
  </code></pre>
  
  <p>INdata:</p>
  
  <pre><code>ID,condition,pain
  1,Treatment,4.5
  3,Treatment,12.5
  4,Treatment,16
  5,Treatment,61.75
  6,Treatment,23.25
  7,Treatment,5.75
  8,Treatment,5.75
  9,Treatment,5.75
  10,Treatment,44.5
  11,Treatment,7.25
  12,Treatment,40.75
  13,Treatment,17.25
  14,Treatment,2.75
  15,Treatment,15.5
  16,Treatment,15
  17,Treatment,25.75
  18,Treatment,17
  19,Treatment,26.5
  20,Treatment,27
  21,Treatment,37.75
  22,Treatment,26.5
  23,Treatment,15.5
  25,Treatment,1.25
  26,Treatment,5.75
  27,Treatment,25
  29,Treatment,7.5
  1,No Treatment,34.5
  3,No Treatment,46.5
  4,No Treatment,34.5
  5,No Treatment,34
  6,No Treatment,65
  7,No Treatment,35.5
  8,No Treatment,48.5
  9,No Treatment,35.5
  10,No Treatment,54.5
  11,No Treatment,7
  12,No Treatment,39.5
  13,No Treatment,23
  14,No Treatment,11
  15,No Treatment,34
  16,No Treatment,15
  17,No Treatment,43.5
  18,No Treatment,39.5
  19,No Treatment,73.5
  20,No Treatment,28
  21,No Treatment,12
  22,No Treatment,30.5
  23,No Treatment,33.5
  25,No Treatment,20.5
  26,No Treatment,14
  27,No Treatment,49.5
  29,No Treatment,7
  </code></pre>
  
  <p>The resulting plot looks like this: </p>
  
  <p><a href="https://i.stack.imgur.com/Bldwy.png" rel="noreferrer"><img src="https://i.stack.imgur.com/Bldwy.png" alt="enter image description here"></a></p>
  
  <p>However, since this is paired data, I want to represent this in the plot - specifically to add lines between paired datapoints. I've tried adding</p>
  
  <pre><code>... + geom_line(aes(group = ID))
  </code></pre>
  
  <p>..but I am not able to implement this into the ggplot2.boxplot code. Instead, I get this error:</p>
  
  <blockquote>
    <p>Error in if (addMean) p &lt;- p + stat_summary(fun.y = mean, geom = "point",  : 
      argument is not interpretable as logical
    In addition: Warning message:
    In if (addMean) p &lt;- p + stat_summary(fun.y = mean, geom = "point",  :
      the condition has length > 1 and only the first element will be used</p>
  </blockquote>
  
  <p>Grateful for any input on this!</p>