# Replicating double histogram for RTs using ggplot2
# (based on R code for FIgure 6-6 on p. 122 of 
# Chang, W. (2013). R graphics cookbook. O'Reilly.

rtdat = read.table("RTs.txt",T)
library(ggplot2)

rtdat$Participant = as.factor(rtdat$Participant)

ggplot(rtdat, aes(x=RT,fill=Participant)) +
 geom_histogram(position="identity", alpha=0.4)