# Perception of points in a swarm

### Description

Five raters were asked to guess the number of points in a swarm for 10 different figures (which - unknown to the raters - were each repeated three times).

### Format

A data frame with 30 observations on the following 6 variables.

- SAND
The true number of points in the swarm. Each picture is replicated thrice

- ME
Ratings from judge 1

- TM
Ratings from judge 2

- AJ
Ratings from judge 3

- BM
Ratings from judge 4

- LO
Ratings from judge 5

### Details

The raters har approximately 10 seconds to judge each picture, and the thought it was 30 different pictures. Before starting the experiment they were shown 6 (unrelated) pictures and were told the number of points in each of those pictures. The SAND column contains the picture id and the true number of points in the swarm.

### Source

Collected by Claus Ekstrom.

### Examples

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 | ```
data(rainman)
long <- data.frame(stack(rainman[,2:6]), figure=factor(rep(rainman$SAND,5)))
figind <- interaction(long$figure,long$ind)
# Use a linear random effect model from the
# lme4 package if available
if(require(lme4)) {
model <- lmer(values ~ (1|ind) + (1|figure) + (1|figind), data=long)
}
#
# Point swarms were generated by the following program
#
set.seed(2) # Original
npoints <- sample(4:30)*4
nplots <- 10
pdf(file="swarms.pdf", onefile=TRUE)
s1 <- sample(npoints[1:nplots])
print(s1)
for (i in 1:nplots) {
n <- s1[i]
set.seed(n)
x <- runif(n)
y <- runif(n)
plot(x,y, xlim=c(-.15, 1.15), ylim=c(-.15, 1.15), pch=20, axes=FALSE,
xlab="", ylab="")
}
s1 <- sample(npoints[1:nplots])
print(s1)
for (i in 1:nplots) {
n <- s1[i]
set.seed(n)
x <- runif(n)
y <- runif(n)
plot(y,x, xlim=c(-.15, 1.15), ylim=c(-.15, 1.15), pch=20, axes=FALSE,
xlab="", ylab="")
}
s1 <- sample(npoints[1:nplots])
print(s1)
for (i in 1:nplots) {
n <- s1[i]
set.seed(n)
x <- runif(n)
y <- runif(n)
plot(-x,y, xlim=c(-1.15, .15), ylim=c(-.15, 1.15), pch=20, axes=FALSE,
xlab="", ylab="")
}
dev.off()
``` |