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Sebastiaan Mathôt
Sebastiaan Mathôt


Current position

I’m currently working as a post-doc at the Laboratoire de Psychologie Cognitive at the CNRS / Aix-Marseille université. My main research interests are Eye movements and perception.

I also maintain, develop OpenSesame, and occasionally make some music.

Scientific publications, presentations, etc.

A list of my scientific publications, presentations, etc. is available here:

Social-network profiles

Miscellaneous writing

I occasionally write blogs about research, academic publishing, and other ‘meta-scientific’ topics. A selection:

Eye movements and perception

Broadly speaking, my research is about eye movements and perception.

Recently, I have become interested in pupillometry. Although pupil size is used routinely as a diagnostic tool in optometry, and as a marker of arousal (or cognitive load, effort, etc.) in a wide range of research fields, there are many things that we still do not know about why, when, and how the pupil changes its size. I’m particularly interested in the relationship between the pupillary response and spatial eye movements, such as saccades and smooth pursuit. If you want to read more about this, see our recent paper in PLoS ONE.

The video below shows the most widely known pupillary response: the light response. This video is based on real data of me viewing an alternating sequence of black and white displays.

During my PhD project at the VU University Amsterdam, I focused on visual stability: How do we construct a stable and complete representation of our environment–if indeed we do!–despite the incompleteness and instability of visual input at the level of the retina? In the video below, you see schematically depicted how the retinal image (on the left) changes as we make eye movements across a visual scene (on the right).


I’m the lead developer of OpenSesame, an open-source graphical experiment builder for the social sciences. OpenSesame is a tool for creating psychological experiments with a minimum of fuzz. Below you can see a demonstration video (courtesy of Chris Longmore).

Other scientific software

In addition to OpenSesame (see above), I have developed a number of other software packages, mostly tools for research and writing (because I like to write about research). Notable packages:

For a full list of software, see:

Feel free to leave a comment! For lengthy discussions and technical questions/ remarks, please refer to the forum.