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Pitch Imagery Arrow Test (PIAT), psychTestR implementation
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README.md

Pitch Imagery Arrow Test (PIAT)

DOI

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

Citation

We are currently preparing an introductory publication for the PIAT. In the meanwhile, when using the PIAT in your own research, you can cite this implementation:

Harrison, P. M. C. (2018). Pitch Imagery Ability Test (PIAT), psychTestR implementation. Zenodo. https://doi.org/10.5281/zenodo.3239098

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:

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

Installation instructions (local use)

  1. If you don't have R installed, install it from here: https://cloud.r-project.org/

  2. Open R.

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

install.packages('devtools')

  1. Install the PIAT:

devtools::install_github('pmcharrison/piat')

Usage

Quick demo

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

# Load the piat package
library(piat)

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

# 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
library(piat)

# 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 http://psychtestr.com/.

Results

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 http://psychtestr.com/). 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: https://www.rstudio.com/products/shiny/download-server/
  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:
library(piat)
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: http://my-web-page.org:3838/piat

Usage notes

  • The PIAT runs in your web browser.
  • By default, audio files are hosted online on our servers. The test therefore requires internet connectivity.
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