## Beginner: application of the rqa in psychology

General discussions and questions about recurrence plot related methods.

### Beginner: application of the rqa in psychology

Hi,
I want to apply crp for a data set which is derived from a eye tracking experiment.
I m not aware of the selection of delay, the neighborhood distance for the recurrence.
Also, my data series format is like the following:
time xPosition yPosition
0 3,76 1,53
0,01 3,39 1,99
0,04 3,71 1,81
0,05 3,56 1,39
0,07 3,52 1,26
0,09 3,34 1,89
0,11 3,22 1,04
0,13 3,28 1,26
0,15 5,27 2,07
0,17 7,94 1,22

my interest would be learn the recurrence of the data for each user and between different users. it is a experiment with 12 users each having 300+ trails in each block. Each user has 4 blocks.

aswin
aswin
Junior

Posts: 2
Joined: Tue May 27, 2014 11:17
Location: Germany

### Re: Beginner: application of the rqa in psychology

you can use the function crp2 in the CRP toolbox. this allows you to consider the x- and y-component as the dimensions of the phase space trajectory directly. if your data vector x is as you wrote with 1st column as time, 2nd column the x-component, and 3rd column the y-component, then you can do
Code: Select all
`crp2(x(:,2:3))`

for RQA analysis you can call the function crqa in the same manner.

Norbert
Expert

Posts: 173
Joined: Wed Jan 4, 2006 11:03
Location: Potsdam Institute for Climate Impact Research, Germany

### Re: Beginner: application of the rqa in psychology

Greetings,
I tried and it was working great!
Now i want to apply the CRP toolbox to study the recurrence between two trails.

The error is "Data must have same length".

Code: Select all
`crqa(eyeTrialLow(:,2:3),eyeTrialHigh(:,2:3))`

my data is looking something like this
time (index1)
515,322000000000
517,674000000000
517,694000000000
517,714000000000
517,734000000000
517,754000000000
517,776000000000
517,794000000000
xComp(index2)
-14,4344460000000
-2,02071250000000
-1,54566600000000
-1,29854700000000
-1,29778800000000
-1,23021650000000
-1,37307200000000
-1,69991700000000
yComp(index3)
-3,79159250000000
-6,21937950000000
-3,26960600000000
-4,37356950000000
-3,01294150000000
-2,38234000000000
-3,22597000000000
-4,02163950000000
aswin
Junior

Posts: 2
Joined: Tue May 27, 2014 11:17
Location: Germany

### Re: Beginner: application of the rqa in psychology

Probably your two data sets have different length. Both for the crqa, both data sets should have equal length.

Norbert
Expert

Posts: 173
Joined: Wed Jan 4, 2006 11:03
Location: Potsdam Institute for Climate Impact Research, Germany