This repository contains a modified version of the OpenMATB software, used for our study "Effects of adaptation accuracy and magnitude in affect-aware difficulty adaptation for the multi-attribute task battery", published in the International Journal of Human-Computer Studies ( https://www.sciencedirect.com/science/article/pii/S1071581923001891 ). The OpenMATB is an open-source reimplementation of the Multi-Attribute Task Battery (MATB). The MATB was first presented at a NASA Technical memorandum (Comstock & Arnegard, 1992) and contained a set of interactive tasks that were representative of those performed in aircraft piloting. OpenMATB was created by Cegarra et al. and is covered by a GPL v3 license, which allows researchers to share their software modifications. The original OpenMATB is available here: https://github.com/juliencegarra/OpenMATB/ and is described in the following publication: Cegarra, J., Valéry, B., Avril, E., Calmettes, C. & Navarro, J. (2020). OpenMATB: An open source implementation of the Multi-Attribute Task Battery. Behavior Research Methods, vol. 52, pp. 1980-1990. https://doi.org/10.3758/s13428-020-01364-w Our modified OpenMATB automates some of the MATB sections, adds multiple difficulty levels and "sham" automated difficulty adaptation (implemented by asking users their preference and following it a predefined percentage of the time), and adds a visual error counter. More details about the modifications are available in our accompanying journal paper (currently submitted for publication, to be updated when accepted).