Musical Emotion Discrimination Test (EDT)

The EDT package contains the adaptive Musical Emotion Discrimination Test (aMEDT), an adaptive test for recognition of emotional interpretation of simple melodies. It also contains also an non-adaptive version (sMEDT) which can still be used, but we highly encourage to use the adaptive version.

Citation

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

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

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')

4. Install the EDT:

devtools::install_github('klausfrieler/EDT')

Usage

Quick demo

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

# Load the EDT package
library(EDT)

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

# Run a demo test, skipping the training phase, and only asking 5 questions, as well a changing the language
EDT_demo(num_items = 5, language = "en")

Testing a participant

The EDT_standalone() function is designed for real data collection. In particular, the participant doesn't receive feedback during this version. Per default, the aMEDT is used. Setting the parameter adaptive to FALSE will run the static version (sMEDT).

# Load the EDT package
library(EDT)

# Run the test as if for a participant, using default settings,
# saving data, and with a custom admin password
# set adaptive = FALSE for static version
EDT_standalone(admin_password = "put-your-password-here", adaptive = TRUE) 

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 EDT_standalone() 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/.

The EDT currently supports English (en), German (de), Russian (ru), and Nederlands (nl). You can select one of these languages by passing a language code as an argument to EDT_standalone(), e.g., EDT_standalone(languages = "de"), or alternatively by passing it as a URL parameter to the test browser, eg. http://127.0.0.1:4412/?language=DE (note that the p_id argument must be empty).

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

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

sudo mkdir EDT

5. 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 EDT/app.R
• Write the following in the text file:

library(EDT)
EDT_standalone(admin_password = "put-your-password-here")

• Save the file (CTRL-O).

6. Change the permissions of your app directory so that psychTestR can write its temporary files there.

sudo chown -R shiny EDT

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

7. Navigate to your new shiny app, with a URL that looks like this: `http://my-web-page.org:3838/EDT

Implementation notes

By default, the adaptive EDT implementation always estimates participant abilities using weighted-likelihood estimation. We adopt weighted-likelihood estimation for this release because this technique makes fewer assumptions about the participant group being tested. This makes the test better suited to testing with diverse participant groups (e.g., children, clinical populations). The static version runs just a fixed sequence of 18 stimuli. Note that the output format of the adaptive and static variants will look rather differently.

Usage notes

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