The literature on human-computer interaction consistently stresses the importance of reducing the cognitive effort required by users who interact with a computer in order to improve the experience and enhance usability and comprehension. Applying this perspective to web surveys, questionnaire designers are advised to strive for layouts that facilitate the response process and reduce the effort required to select an answer. In this article, we examine whether placing the answer boxes (i.e., radio buttons or check boxes) to the left or to the right of the answer options in closed questions with vertically arranged response categories enhances usability and facilitates responding. First, we discuss a set of opposing principles of how respondents may process these types of questions in web surveys, some suggesting placing the answer boxes to the left and others suggesting placing them to the right side of the answer options. Second, we report an eye-tracking experiment that examined whether web survey responding is best described by one or another of these principles, and consequently whether one of the three layouts is preferable in terms of usability: (1) answer boxes to the left of left-aligned answer options, (2) answer boxes to the right of left-aligned answer options, and (3) answer boxes to the right of right-aligned answer options. Our results indicate that the majority of respondents conform to a principle suggesting placing the answer boxes to the left of left-aligned answer options. Moreover, respondents require less cognitive effort (operationalized by response latencies, fixation times, fixation counts, and number of gaze switches between answer options and answer boxes) to select an answer in this layout.