While eye tracking is gaining popularity in IS research, pupillometry is relatively less explored in IS eye tracking studies. Research however suggests that pupillometry may serve as an excellent unobtrusive measure to study user information processing behavior. The Adaptive decision making theory asserts that task demand affects information processing behavior. Grounded in this theory, we argue that users’ pupillary responses will be different under different task conditions (task demand). We tested our assertion via an eye tracking laboratory experiment. Our results show that pupillary responses were significantly different under different task conditions.