This study focused on the prediction of intrinsic and extraneous cognitive load using eye-tracking metrics, heart rate variability, and galvanic skin response. Intrinsic cognitive load is associated with the inherent complexity of the mental task, whereas extraneous cognitive load is related to the distracting and unrelated elements in the task. Thirty-three participants (aged \(21.24 \pm 3.51\) ) performed different levels of mental calculations to induce intrinsic cognitive load in the first task and a visual search task to manipulate extraneous cognitive load in the second task. During both tasks, participants’ eye movements, heart rate, and galvanic skin response were continuously recorded. Participants’ working memory was controlled. Subjective cognitive load was also assessed following each experimental task. A discriminant model, consisting of oculo- and bio-metric indicators, could discriminate between cognitive loads (intrinsic vs.extraneous) and levels (low vs.high). In particular, average fixation duration, average saccade amplitude, and \(\mathscr {K}\) coefficient each have an impact on the model. In addition, task difficulty may be distinguished by the Low-High Index of Pupillary Activity (LHIPA) and heart rate variability.
