Introduction

People typically respond faster to target stimuli whose location has previously been "cued". However, this effect turns around when the interval between cue and target is over 300 m (Klein, 20000). This latter effect is known as Inhibition Of Return (IOR).

Interestingly, IOR is not observed when the cue is endogenous and when no saccades are being made.

In a study by Filotheo and colleagues (1997), healthy individuals and people suffering from Parkinson’s disease were compared in both endogenous and exogenous cueing. The prediction is that when people are not making saccades (e.g., because they have been instructed to keep fixating on the fixation point), there should only be IOR in the exogenous condition. But is that true? Try it yourself!

About this implementation

This implementation requires a numeric keyboard!

Run the demo

In this example, you will

Data output file

In PsyToolkit, the data output file is simply a textfile. The save line of the PsyToolkit experiment script determines what is being saved in the data output file. Typically, for each experimental trial, you would have exactly one line in your text file, and each number/word on that line gives you the information you need for your data analysis, such as the condition, response speed, and whether an error was made.

Meaning of the columns in the output datafile. You need this information for your data analysis.

Colum Meaning BLOCKNAME &training $cuetype $valid $SOA $waitkeytime $tooearly $cue $target STATUS RT

1

Name of block

2

Training (0=no training block, 1=training block)

3

Type of cue (1=endogenous, 2=exogenous)

4

cue validity (0=invalid, 1=valid)

5

soa (time between cue and target, 50, 150, 250, 1000 ms)

6

the time the participant waited to press the central button

7

was response too early (0=no, 1=yes)

8

cue position (1=left, 2=top, 3=right, 4=bottom)

9

target position (1=left, 2=top, 3=right, 4=bottom)

10

Status (1=correct, 2=wrong, 3=timeout)

11

Reaction time (ms)

Download

If you have a PsyToolkit account, you can upload the zipfile directly to your PsyToolkit account. Watch a video on how to do that. If you want to upload the zipfile into your PsyToolkit account, make sure the file is not automatically uncompressed (some browsers, especially Mac Safari, by default uncompress zip files). Read here how to easily deal with this.

Further reading

  • Filoteo, J.V., Delis, D.C., Salmon, D.P., Demadura, T., Roman, M.J. & Shults, C. W. (1997). _Journal of the International Neuropsychological Society, 3, 337-347.