cognitive science
and more


About me

Photos by Sander Martens

I'm an assistant professor at the department of experimental psychology of the University of Groningen in the Netherlands. My main research interests are eye movements, pupillometry, and perception. I also maintain and develop OpenSesame.

Find me on:


Feel free to send me an e-mail:

I kindly ask that you post support questions (for OpenSesame and other software packages) on the forum. I do not provide technical support through e-mail.

Miscellaneous writing

Short stories (fiction)

I occasionally write short fictional stories. I don't publish these stories as such. But I do make little handmade booklets of them, which I give away, hide in book exchanges, and sell on a small scale. If you want to know more, visit

I write blogs about (my) research, academic publishing, and other 'meta-scientific' topics.

About my research

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

I've recently become interested in pupillometry, and particularly in the role that pupil-size changes play in how we perceive the world. Why do our pupils constrict (become smaller) when we look at something bright? And how is the pupillary light response modulated by things like attention, working memory, and eye movements? Why do our pupils dilate (become bigger) when we become aroused? And what is the link between arousal-related dilation and the light response? These are all questions that fascinate me. If you want to read more about this topic, see our recent papers on the topic, and in particular my review article in Journal of Cognition.

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

To see what (or rather: one of the many things that) you can do with pupillometry, check out this video:

Which I explain in more detail here:

And another video in which I talk about (and speculate on) the relationship between pupil size and arousal:

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).

Scientific publications, presentations, etc.

Research in progress (pre-prints)

The pre-prints listed below have been made available for community feedback, and to share our newest findings as quickly as possible, prior to formal publication. However, these pre-prints have not yet undergone peer review and may be revised as the work progresses.

Mathôt, S., & Vilotijević, A. (2022). Methods in Pupillometry: Design, Preprocessing, and Statistical Analysis. bioRxiv. doi:10.1101/2022.02.23.481628

Zhou, C., Lorist, M., & Mathôt, S. (2021). Is categorization in visual working memory a way to reduce mental effort? A pupillometry study. bioRxiv. doi:10.1101/2021.11.23.469689

Chen, I., Karabay, A., Mathôt, S., Bowman, H., & Akyürek, E.G. (2021). Concealed identity information detection with pupillometry in rapid serial visual presentation. bioRxiv. doi:10.1101/2021.06.18.448944

Regnath, F., & Mathôt, S.. (2021). Pupil size reflects exploration and exploitation in visual search (and it's like object-based attention) bioRxiv. doi:10.1101/2021.02.05.429946

Mathôt, S., Sundermann, L., & Van Rijn, H. (2019). The effect of semantic brightness on pupil size: A replication with Dutch words. bioRxiv. doi:10.1101/689265

Publications (peer reviewed)

Many papers are open access and can be freely downloaded from the publisher via the doi: links. For papers that are paywalled or not yet officially available, an unofficial pre-print is available via the "free pdf" links.

Registered reports with Stage 1 (in principle) acceptance

The manuscripts listed below are registered reports that have been accepted after peer review, but that have not yet been finalized.

Zhou, C., Lorist, M., Mathôt, S., (2021). Are eye movements guided by working-memory templates during visual search in naturalistic environments? Memory.
Related preprint (with initial data)

2022 / online first / in press

Mathôt, S., & March, J. (in press). Conducting linguistic experiments online with OpenSesame and OSWeb. Language Learning.
Related preprint (not identical to published manuscript)

Wardhani, I. K., Boehler, C. N., & Mathot, S. (2022). The influence of pupil responses on subjective brightness perception. Perception. doi:10.1177/03010066221094757

Wilschut, T., & Mathôt, S. (2022). Interactions between visual working memory, attention, and color categories: a pupillometry study. Journal of Cognition. doi:10.5334/joc.208

Zhou, C., Lorist, M., Mathôt, S., (in press). Categorical bias as a crucial parameter in visual working memory: The effect of memory load and retention interval. Cortex.
Related preprint


Pittarello, A., Frătescu, M., & Mathot, S. (2021). We remember the past as more rewarding than it was: effects of temptation on cheating and visual working memory. Current Psychology. doi:10.1007/s12144-021-02339-6

Wahn, B., Ruuskanen, V., Kingstone, A., & Mathot, S. (2021). Coordination effort in joint action is reflected in pupil size. Acta Psychologica. doi:10.1016/j.actpsy.2021.103291
Related preprint (not identical to published manuscript)


Mathôt, S. (2020). Tuning the senses: How the pupil shapes vision at the earliest stage. Annual Review of Vision Science. doi:10.1146/annurev-vision-030320-062352
Free PDF download

Brysbaert, M., Bakk, Z., Buchanan, E.M. et al. (2020). Editorial: Into a new decade. Behavior Research Methods. doi:10.3758/s13428-020-01497-y

Wardhani, I.K., Mathôt, S., Boehler, C.N., Laeng, B. (2020). Effects of nicotine on pupil size and performance during multiple-object tracking in non-nicotine users. International Journal of Psychophysiology. doi:10.1016/j.ijpsycho.2020.09.005
Related preprint (not identical to published manuscript)

Zhou, C., Lorist, M., & Mathôt, S. (2020). Concurrent guidance of attention by multiple working memory items: Behavioral and computational evidence. Attention, Perception, & Psychophysics. doi:10.3758/s13414-020-02048-5
Related preprint (not identical to published manuscript)


Mathôt, S., & Ivanov, Y. (2019). The effect of pupil size and peripheral brightness on detection and discrimination performance. PeerJ, e8820. doi:10.7717/peerj.8220
Related preprint (not identical to published manuscript)

Hustá, C., Dalmaijer, E., Belopolsky, A., & Mathôt, S. (2019). The pupillary light response reflects visual working memory content. Journal of Experimental Psychology: Human Perception and Performance. doi:10.1037/xhp0000689
Related preprint (not identical to published manuscript)

Frătescu, M., Van Moorselaar, D., & Mathôt, S. (2019). Can you have multiple attentional templates? Large-scale replications of Van Moorselaar, Theeuwes and Olivers (2014) and Hollingworth and Beck (2016). Attention, Perception, & Psychophysics. doi:10.3758/s13414-019-01791-8
Related preprint (not identical to published manuscript)

Pittarello, A., Frătescu, M., & Mathôt, S. (2019). Visual saliency influences ethical blind spots and (dis)honesty. Psychonomic Bulletin & Review. doi:10.3758/s13423-019-01638-1

Soleymani, A. Ivanov, Y., Mathôt, S., & De Jong, P. (in press). Free viewing eye tracking task to index attention bias for alcohol cues: Satisfactory reliability and criterion validity. Addictive Behaviors. doi:10.1016/j.addbeh.2019.106117

Hanke, M., Mathôt, S., Ort, E., Peitek, K., Stadler, J., & Wagner, A. (in press). A practical guide to functional magnetic resonnce imaging with simultaneous eye tracking for cognitive neuroimaging research. Neuromethods. doi:10.1007/7657_2019_31


Mathôt, S. (2018). Pupillometry: Psychology, physiology, and function. Journal of Cognition. doi:10.5334/joc.18

Mathôt, S., Fabius, J., Heusden, E. V., & Van der Stigchel, S. (2018). Safe and sensible preprocessing and baseline correction of pupil-size data. Behavior Research Methods. doi:10.3758/s13428-017-1007-2

Mathôt, S., & Naber, M. (2018), There is no evidence that pupil mimicry is a social phenomenon. Proceedings of the National Academy of Sciences. doi:10.1073/pnas.1814429115
See also the reply by Prochazkova et al. and this blog post

Derksen, M., van Alphen, J., Schaap, S., Mathôt, S., & Naber, M. (2018). Pupil mimicry is the result of brightness perception of the iris and pupil. Journal of Cognition. doi:10.5334/joc.34

Snell, J., Mathôt, S., Mirault, J., & Grainger, J. (2018). Parallel graded attention in reading: A pupillometric study. Scientific Reports. doi:10.1038/s41598-018-22138-7

Van Hooijdonk, R., Mathôt, S., Schat, E., Spencer, H., Van der Stigchel, S., & Dijkerman, H. C. (2018). Touch-induced pupil size reflects stimulus intensity, not subjective pleasantness. Experimental Brain Research. doi:10.1007/s00221-018-5404-2


Mathôt, S., Grainger, J., & Strijkers, K. (2017). Pupillary responses to words that convey a sense of brightness or darkness. Psychological Science. doi:10.1177/0956797617702699
Discussed on YouTube, CNRS (French), RUG (Dutch), CQFD (Radio Suisse, French), Radio Canada (French), ZME Science, Science Actualités (French), Sciences et Avenir (French), De Taalstaat (Radio 1, Dutch), Dagblad van het Noorden (Dutch)

Fabius, J.H., Mathôt, S., Schut, M.J., Nijboer,T.C.W. & Van der Stigchel, S. (2017). Focus of spatial attention during spatial working memory maintenance: Evidence from pupillary light response. Visual Cognition. doi:10.1080/13506285.2017.1311975

Ferrand, L., Méot, A., Spinelli, E., New, B., Pallier, C., Bonin, P., Dufau, S., Mathôt, S., & Grainger, J. (2017). MEGALEX: A megastudy of visual and auditory word recogntion. Behavior Research Methods. doi:10.3758/s13428-017-0943-1

Marzouki, Y., Dusaucy, V., Chanceaux, M., & Mathôt, S. (2017). The World (of Warcraft) through the eyes of an expert. PeerJ, 5, e3783. doi:10.7717/peerj.3783

Stigchel, S. V. der, & Mathôt, S. (2017). Don’t admit defeat: A new dawn for the item in visual search. Behavioral and Brain Sciences. doi:10.1017/S0140525X16000285
Comment on Hulleman & Olivers (2016)


Mathôt, S., Melmi, J.-B, van der Linden, S., & Van der Stigchel, S. (2016). The mind-writing pupil: A human-computer interface based on decoding of attention through pupillometry. PLoS ONE, 11(2), e0148805. doi:10.1371/journal.pone.0148805
Discussed on 20 Minutes (French), ARTE Future (German / French), CNRS (French),, La Marseillaise (French), Sublime News (Dutch), (French), De Telegraaf (Dutch), Utrecht University (Dutch), YouTube

Blom, T., Mathôt, S., Olivers, C.N.L., & Van der Stigchel, S. (2016). The pupillary light response reflects encoding, but not maintenance, in visual working memory. Journal of Experimental Psychology: Human Perception and Performance, 42(11), 1716-1723. doi:10.1037/xhp0000252
Download free pdf

Pinet, S., Zielinski, C., Mathôt, S., Dufau, S., Alario, F.-X., Longcamp, M. (2016). Measuring sequences of keystrokes with jsPsych: reliability of response times and interkeystroke intervals. Behavior Research Methods. doi:10.3758/s13428-016-0776-3
Download free pdf


Mathôt, S., & Van der Stigchel, S. (2015). New light on the mind’s eye: The pupillary light response as active vision. Current Directions in Psychological Science, 24(5), 374–378. doi:10.1177/0963721415593725
Discussed on Psychology Today

Mathôt, S., Melmi, J.-B., & Castet, E. (2015). Intrasaccadic perception triggers pupillary constriction. PeerJ, 3(e1150), 1–16. doi:10.7717/peerj.1150
Discussed on

Mathôt, S., Siebold, A., Donk, M., & Vitu, F. (2015). Large pupils predict goal-driven eye movements. Journal of Experimental Psychology: General, 144(3), 513-521. doi:10.1037/a0039168
Download free pdf and supplementary pdf
Discussed on

Mathôt, S., van der Linden, L., Grainger, J., & Vitu, F. (2015). The pupillary light response reflects eye-movement preparation. Journal of Experimental Psychology: Human Perception and Performance, 41(1), 28–35. doi:10.1037/a0038653
Download free pdf

van der Linden, L., Mathôt, S., Vitu, F. (2015). The role of object affordances and center of gravity in eye movements towards isolated daily-life objects. Journal of Vision, 15(5), e8. doi:10.1167/15.5.8


Mathôt, S., Dalmaijer, E., Grainger, J., & Van der Stigchel, S. (2014). The pupillary light response reflects exogenous attention and inhibition of return. Journal of Vision, 14(14), 7. doi:10.1167/14.14.7
Discussed on

Chanceaux, M., Mathôt, S., & Grainger, J. (2014). Effects of number, complexity, and familiarity of flankers on crowded letter identification. Journal of Vision, 14(6), 7. doi:10.1167/14.6.7

Dalmaijer, E., Mathôt, S., & Van der Stigchel, S. (2014). PyGaze: An open-source, cross-platform toolbox for minimal-effort programming of eyetracking experiments. Behavior Research Methods, 46(4), 913–921. doi:10.3758/s13428-013-0422-2
Download free pdf

Grainger, J., Mathôt, S., & Vitu, F. (2014). Tests of a model of multi-word reading: Effects of parafoveal flanking letters on foveal word recognition. Acta Psychologica, 146, 35-40. doi:10.1016/j.actpsy.2013.11.014
Download free pdf

Theeuwes, J., Mathôt, S., & Grainger, J. (2014). Object-centered orienting and IOR. Attention, Perception, & Psychophysics, 76(8), 2249–2255. doi:10.3758/s13414-014-0718-z


Mathôt, S., van der Linden, L., Grainger, J., & Vitu, F. (2013). The pupillary response to light reflects the focus of covert visual attention. PLoS ONE, 8(10), e78168. doi:10.1371/journal.pone.0078168
Discussed on, Janne in Osaka

Mathôt, S., & Theeuwes, J. (2013). A reinvestigation of the reference frame of the tilt-adaptation aftereffect. Scientific Reports, 3, e1152. doi:10.1038/srep01152

Chanceaux, M., Mathôt, S., & Grainger, J. (2013). Flank to the left, flank to the right: Testing the modified receptive field hypothesis of letter-specific crowding. Journal of Cognitive Psychology, 25(6), 774-780. doi:10.1080/20445911.2013.823436
Download free pdf

Talsma, D., White, B., Mathôt, S., Munoz, D., & Theeuwes, J. (2013). A retinotopic attentional trace after saccadic eye movements: Evidence from event-related potentials. Journal of Cognitive Neuroscience, 25(9), 1563-1577. doi:10.1162/jocn_a_00390
Download free pdf

Theeuwes, J., Mathôt, S., Grainger, J. (2013). Exogenous object-centered attention. Attention, Perception, & Psychophysics. 75, 812-818. doi:10.3758/s13414-013-0459-4
Download free pdf


Mathôt, S., & Theeuwes, J. (2012). It's all about the transient: Intra-saccadic onset stimuli do not capture attention. Journal of Eye Movement Research, 5(2):4, 1-12. doi:10.16910/jemr.5.2.4

Mathôt, S., Cristino, F., Gilchrist, I.D., & Theeuwes, J. (2012). A simple way to estimate similarity between pairs of eye movement sequences. Journal of Eye Movement Research, 5(1):4, 1-15. doi:10.16910/jemr.5.1.4

Mathôt, S., Schreij, D., & Theeuwes, J. (2012). OpenSesame: An open-source, graphical experiment builder for the social sciences. Behavior Research Methods, 44, 314-324. doi:10.3758/s13428-011-0168-7


Mathôt, S., & Theeuwes, J. (2011). Mantra: An open method for object and movement tracking. Behavior Research Methods, 43(4), 1182-1193. doi:10.3758/s13428-011-0105-9

Mathôt, S., & Theeuwes, J. (2011). Visual attention and stability. Philosophical Transactions of the Royal Society B: Biological Sciences, 366(1564), 516-527. doi:10.1098/rstb.2010.0187
Download free pdf


Cristino, F., Mathôt, S., Theeuwes, J., & Gilchrist, I. D. (2010). ScanMatch: A novel method for comparing fixation sequences. Behavior Research Methods, 42(3), 692-700. doi:10.3758/BRM.42.3.692
Download free pdf

Mathôt, S., Hickey, C., & Theeuwes, J. (2010). From reorienting of attention to biased competition: Evidence from hemifield effects. Attention, Perception & Psychophysics, 72(3), 651-657. doi:10.3758/APP.72.3.651
Download free pdf

Mathôt, S., & Theeuwes, J. (2010). Gradual remapping results in early retinotopic and late spatiotopic inhibition of return. Psychological Science, 21(12), 1793-1798. doi:10.1177/0956797610388813
Download free pdf

Mathôt, S., & Theeuwes, J. (2010). Evidence for the predictive remapping of visual attention. Experimental Brain Research, 200(1), 117-122. doi:10.1007/s00221-009-2055-3

Theeuwes, J., Mathôt, S., & Kingstone, A. (2010). Object-based eye movements: The eyes prefer to stay within the same object. Attention, Perception & Psychophysics, 72(3), 12–21. doi:10.3758/APP.72.3.597
Download free pdf


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:

Editorial activities

I'm currently on the editorial board of the following journals:

Grants, awards, and sponsorships

2021 Sep - 2026 Sep

Innovational Research Incentives Scheme VIDI
Tuning the senses: how cognition shapes sensation at the gate (Grant VI.Vidi.191.045, €799,981)

2016 Nov - 2019 Nov

Innovational Research Incentives Scheme VENI
The Active Pupil 2.0: A feedback loop between perception, mental state, and pupil size (Grant 016.Veni.175.078, €246,439)

2016 Dec - 2018 Dec

Collaboration grant (with Andrea Pittarello)
Grant by Faculty of Behavioural and Social Sciences of the University of Groningen to encourage inter-departmental collaborations (€14,400)

2015 May - 2019 May

European Society for Cognitive Psychology (ESCOP)
Sponsorship OpenSesame

2014 Nov - 2016 Oct

Marie Curie Intra-European Fellowship FP7-PEOPLE-2013-IEF
The Active Pupil: The role of pupil size in active vision (Grant #622738, €194,047)

2014 Jan - 2015 Jan

Ipskamp publishers, Enschede, The Netherlands

2012 Sep - Running

SR Research, Missisauga, ON, Canada
Sponsorship OpenSesame

2016 Mar

Actions Incitatives de la Fédération 3C, Marseille, France
Rapid development of online behavioral experiments with OpenSesame (€5,000)

2015 Sep

Center for Open Science, Charlottesville, VA, United States
Incubator grant for integration between the Open Science Framework and OpenSesame ($15,000)

2015 Aug

Center for Open Science, Charlottesville, VA, United States
Planning grant for open-source behavioral research infrastructure and OSF integration ($2,000)

2014 May

Best Illusion of the Year Contest, St. Pete Beach, FL, United States
Top 10 finalist with the illusion Infinite Maze

2013 Dec

Dutch Psychonomic Society (De Nederlandse Veriniging voor Psychonomie)
Biennial award for best Dutch PhD thesis in the field of experimental psychology (€500)

2012 Oct

Tilburg University, Netherlands
Sponsorship OpenSesame

2012 Nov

Ipskamp publishers, Enschede, The Netherlands
Sponsorship printing costs PhD thesis (approx. €1000)

2012 Jan

VU University, Amsterdam, The Netherlands
Talent-budget grant (€5,500)

2009 Jan

VU University, Amsterdam, The Netherlands
Prize for best master's thesis from the faculty of psychology and education. (€450)

2008 Oct

Rovereto Attention Workshop, Trento, Italy
Award for best poster (€400)