In-lab versus web-based eye-tracking in decision-making: A systematic comparison on multiple display-size conditions...

Eye-tracking has gained considerable attention across multiple research domains. Recently, web-based eye-tracking has become feasible, demonstrating reliable performance in perceptual and cognitive tasks. However, its systematic evaluation in decision-making remains unknown. Here we compare a laboratory-based eye tracker (the EyeLink 1000 Plus) with a webcam-based method (WebGazer) across two discrete-choice experiments. We systematically manipulated display size to approximate common device classes (monitor, laptop, tablet, mobile) and task complexity (simple vs. complex choice matrices). We find that on larger displays and simpler tasks, WebGazer produces gaze patterns and parameter inferences from computational models of behavior comparable to EyeLink. However, reliability diminishes on smaller displays and with more complex choice matrices. These results provide the first systematic evaluation of web-based eye tracking for decision-making research and offer practical guidance regarding its viability for online behavioral studies.