Best practices for eye-tracking experiments
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This page lists some recommendations and hard constraints for eye-tracking experiments. Note that neither the list nor the explanations are meant to be exhaustive, and consulting the literature on specific topics is always recommended.
| Parameter / Setting | Explanation | Reading |
|---|---|---|
| Background color | In order not to strain paticipants eyes by having to look at a bright screen, it is common to use a gray background and not white. Black or too dark with white font color is also not recommended. | Â |
| Font size | The font size should be large enough so that participants can read without tiring too much. The font size defines how many characters per degree of visual angle each participant sees and it is therefore crucial for comparability across experiments. Depends on the monitor used and the eye-to-screen distance and has to be tested in the lab. | Â |
| Monospaced font | When using a monospaced font, each character on the screen covers the same horizontal width. This means that the visual length of a word is not influenced by the letters it is composed of. It needs to be decided for each experiment whether a monospaced font is suitable and necessary for analses, e.g., to avoid confunds. | Schotter, E.R., Dillon, B. A beginner’s guide to eye tracking for psycholinguistic studies of reading. Behav Res 57, 68 (2025). https://doi.org/10.3758/s13428-024-02572-4 Hautala, J., Loberg, O., & Leinonen, S. (2012). Dissociating spatial and letter-based word length effects observed in readers’ eye movement patterns. Vision Research, 51(18), 2082–2092. https://doi.org/10.1016/j.visres.2011.07.005 |
| Spacing | The line spacing in reading tasks is typically larger than in texts read in daily life. This is related to the precision of the eye-tracker and that it is not always very easy to map the gaze to specific areas (e.g., word) on the text if there is imprecision. | Hooge, I.T.C., Nyström, M., Niehorster, D.C. et al. The fundamentals of eye tracking part 6: Working with areas of interest. Behav Res 58, 65 (2026). https://doi.org/10.3758/s13428-025-02937-3 |
| Number of filler items | For latin square experiment designs, it is important that there are enough filler items among the experimental items. Otherwise, participants can be able to guess the purpose of the experiment if items are very similar. | Â |
| Stimulus area | The stimulus area HAS to be in the trackable range of your eye-tracker. Please consult the manual prior to defining the size. | Your eye-tracker manual. |