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Adaptive Pitch Imagery Arrow Test (aPIAT)

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The aPIAT is an adaptive test of pitch imagery abilities. We invite you to try the test here.


You can cite the aPIAT as follows:

Gelding, R., Harrison, P. M. C., Silas, S., Johnson, B. W., Thompson, W. F., and Müllensiefen, D., 2020. Developing an efficient test of musical imagery ability: Applying modern psychometric techniques to the Pitch Imagery Arrow Task. Psychological Research.

We also advise mentioning the software versions you used, in particular the versions of the piat, psychTestR, and psychTestRCAT packages. You can find these version numbers from R by running the following commands:

if (!require(devtools)) install.packages("devtools")
x <- devtools::session_info()
x$packages[x$packages$package %in% c("piat", "psychTestR", "psychTestRCAT"), ]

You can cite psychTestR as follows:

Harrison, Peter M. C. (2020). psychTestR: An R package for designing and conducting behavioural psychological experiments. Journal of Open Source Software.

Installation instructions (local use)

  1. If you don't have R installed, install it from here:

  2. Open R.

  3. Install the ‘devtools’ package with the following command:


  1. Install the PIAT:



Quick demo

You can demo the PIAT at the R console, as follows:

# Load the piat package

# Run a demo test, with feedback as you progress through the test,
# and not saving your data

# Run a demo test, skipping the training phase, and only asking 5 questions
demo_piat(num_items = 5, take_training = FALSE)

Testing a participant

The standalone_piat() function is designed for real data collection. In particular, the participant doesn't receive feedback during this version.

# Load the piat package

# Run the test as if for a participant, using default settings,
# saving data, and with a custom admin password
standalone_piat(admin_password = "put-your-password-here")

You will need to enter a participant ID for each participant. This will be stored along with their results.

Each time you test a new participant, rerun the standalone_piat() function, and a new participation session will begin.

You can retrieve your data by starting up a participation session, entering the admin panel using your admin password, and downloading your data. For more details on the psychTestR interface, see

The PIAT uses video files that are currently stored on our media servers. As a result, it requires an internet connection to function properly.

The PIAT currently supports English (EN) and German (DE). If you would like to add a new language to this list, please contact us. You can select one of these languages by passing a language code as an argument to standalone_piat(), e.g. standalone_piat(languages = "DE"), or alternatively by passing it as a URL parameter to the test browser, eg. (note that the p_id argument must be empty). Please note that the demo version of the test (demo_piat) currently only supports English.


The main output from the PIAT is an ability score, corresponding to the ability estimate for the participant. It is computed from the underlying item response model and ranges approximately from -4 to +4. A secondary output is an ability_sem score, corresponding to the standard error of measurement for the ability estimate; again, it is computed from the underlying IRT model. For most applications you would only use the ability value, unless using a statistical analysis technique that allows you to specify measurement error explicitly. For more information about item response theory, see the Wikipedia article.

psychTestR provides several ways of retrieving test results (see Most are accessed through the test's admin panel.

  • If you are just interested in the participants' final scores, the easiest solution is usually to download the results in CSV format from the admin panel.
  • If you are interested in trial-by-trial results, you can run the command compile_trial_by_trial_results() from the R console (having loaded the MDT package using library(piat)). Type ?compile_trial_by_trial_results() for more details.
  • If you want still more detail, you can examine the individual RDS output files using readRDS(). Detailed results are stored as the 'metadata' attribute for the ability field. You can access it something like this:
x <- readRDS("output/results/id=1&p_id=test&save_id=1&pilot=false&complete=true.rds")
attr(x$PIAT$ability, "metadata")

Installation instructions (Shiny Server)

  1. Complete the installation instructions described under 'Local use'.
  2. If not already installed, install Shiny Server Open Source:
  3. Navigate to the Shiny Server app directory.

cd /srv/shiny-server

  1. Make a folder to contain your new Shiny app. The name of this folder will correspond to the URL.

sudo mkdir piat

  1. Make a text file in this folder called app.R specifying the R code to run the app.
  • To open the text editor: sudo nano piat/app.R
  • Write the following in the text file:
standalone_piat(admin_password = "put-your-password-here")
  • Save the file (CTRL-O).
  1. Change the permissions of your app directory so that psychTestR can write its temporary files there.

sudo chown -R shiny piat

where shiny is the username for the Shiny process user (this is the usual default).

  1. Navigate to your new shiny app, with a URL that looks like this:


Pitch Imagery Arrow Test (PIAT), psychTestR implementation




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