Introduction

The Corsi test or "Corsi block-tapping test" is a short term memory task conceptually similar to the digit span test. It is named after the creator Philip Michael Corsi, who developed this test as part of his doctoral training (PhD, you can download this original work from 1972, see references at bottom of this page).

Corsi was supervised by the well-known neuropsychologist Brenda Milner.

This task was originally not designed as a computer task.

In this task:

  1. the experimenter (the person who carries out the study) shows nine blocks arranged in front of the participant,

  2. the experimenter taps a sequence of blocks (for example, the experimenter taps a sequence of 3 different blocks, one after another),

  3. the participant needs to tap the blocks that the experimenter showed, in the same order,

  4. steps 1-3 are repeated multiple times with different lengths of blocks.

The block span or Corsi span is defined as the longest sequence a participant can correctly repeat.

Kessels and colleagues (2000) carried out a study with healthy participants and participants with some form of brain damage. In their study, healthy adults had an average block span of 6.2 blocks (SD=1.3). Thus, if you are healthy, you are most likely to have a block span of somewhere between 5 and 7 blocks. That is, 68% of the population scores 1 standard deviation from the mean, so if you belong to this 68%, you would have a Corsi block span between 5 and 7 blocks. You can test this yourself with the demo below.

The normal (average) score is around 6. The highest possible block span in this task is 9. In principle, there might be people who can do better, but that will be quite rare.

About this implementation

  • In this implementation, we start with a sequence of 2 blocks

  • Once the sequence has been shown, you hear the word "go" (if you have your speakers on)

  • You need to click with the mouse the blocks in exactly the same order as shown before

  • When you are done, you click the green block "done"

  • You get feedback (smiley face means you did it correct, or frowny face if you made a mistake)

  • If you do it correctly, you go the the next higher number of blocks

  • If you do it wrong, you get once more chance. If you do it then wrong again, you get your score (the Corsi block span)

Run the demo

In this example, you will carry out the Corsi task. You will see further instructions. You need a mouse and ideally you would have sound speakers (because after the sequence is shown, a voice will say "go"). But even without sound, it is fairly obvious when the sequence ends and when you need to start.

Data output file

You do not need this information, unless you want to understand the output data file. You can ignore this if you just want to find out your own score. This is only necessary if you want to carry out the experiment with multiple participants.
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

1

The highest Corsi span so far

2

The number of items in the current trial to be remembered (starting with 2)

3

Status of current trial (1=correct, 0=wrong)

4

The table row from the table (this experiment comes with 500 random block arrangements and sequences)

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

  • Corsi, P.M. (1972). Human memory and the medial temporal region of the brain. Doctoral Thesis at McGill University (Canada). Download from here.

  • Kessels, R.P.C., van Zandvoort, M.J.E., Postman, A., Kapelle, L.J., & de Hand, E.H.F. (2000). The Corsi Block-Tapping Task: Standardization and Normative Data. Applied Neuropsychology, 7(4), 252-258.