Do your eye movements reveal your performance on an IQ test? A study linking eye movements and socio-demographic information to fluid intelligence.

Abstract

Understanding the main factors contributing to individual differences in fluid intelligence is one of the main challenges of psychology. A vast body of research and numerous empirical findings are based on the framework of the Cultural-Fair IQ test 20-R (CFT 20-R). In this work, we extend and complement the current state of research by analysing the relationship of socio-demographic and eye-movement-related information and the ability of a participant to correctly solve a CFT test item. Our work shows that a participant's eye movements while solving a CFT test item contain discriminative information and can be used to predict whether the participant will succeed in the current task. Moreover, the information related to eye movements complements the information provided by socio-demographic data when it comes to success prediction. In combination, both types of information yield a significantly higher predictive performance than each information type individually. To better understand the influence of features related to eye movements and socio-demographic information for the prediction of a participant's performance on a CFT item, we employ state-of-the-art explainability techniques and show that, along with socio-demographic variables, eye-movement data, especially the number of saccades and the mean pupil diameter, adds highly discriminating power. This ultimately suggests more efficient processing and more invested mental effort. Beyond the specific contribution to research on the relationship between eye movements and fluid intelligence, the findings presented in this work pave the way for further in-depth investigations of factors predicting fluid intelligence.