Open AccessClassifying the difficulty levels of working memory tasks by using pupillary response
Author(s) -
Hugo MitreHernandez,
Jorge E. Sánchez-Rodríguez,
Sergio Nava-Muñoz,
Carlos Lara-Álvarez
Publication year - 2022
Publication title -
peerj
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.927
H-Index - 70
ISSN - 2167-8359
DOI - 10.7717/peerj.12864
Subject(s) - linear discriminant analysis , memorization , pupil , support vector machine , artificial intelligence , random forest , decision tree , computer science , pupillary response , pupil size , classifier (uml) , pupillometry , machine learning , pattern recognition (psychology) , psychology , cognitive psychology , neuroscience
Knowing the difficulty of a given task is crucial for improving the learning outcomes. This paper studies the difficulty level classification of memorization tasks from pupillary response data. Developing a difficulty level classifier from pupil size features is challenging because of the inter-subject variability of pupil responses. Eye-tracking data used in this study was collected while students solved different memorization tasks divided as low-, medium-, and high-level. Statistical analysis shows that values of pupillometric features (as peak dilation, pupil diameter change, and suchlike) differ significantly for different difficulty levels. We used a wrapper method to select the pupillometric features that work the best for the most common classifiers; Support Vector Machine (SVM), Decision Tree (DT), Linear Discriminant Analysis (LDA), and Random Forest (RF). Despite the statistical difference, experiments showed that a random forest classifier trained with five features obtained the best F1-score (82%). This result is essential because it describes a method to evaluate the cognitive load of a subject performing a task using only pupil size features.