Psychophysiology of Perception



The aim of the Psychophysiology of Perception laboratory is twofold:

(1) to conduct scientific experiments to learn about perception and psychophysiology. This includes (i) learning about perception using physiological (including neuroscientific) measures, (ii) learning about biological and neuroscientific mechanisms underlying psychophysiological responses, and (iii) learning about how mental processes are reflected in physiological responses.

(2) to conduct valorisation studies in practice to utilize scientific knowledge for society in general, governments, education, and commercial businesses. This includes (i) reading a person's mental perceptions, states, thoughts, and intentions with physiological measures, (ii) finding biomarkers for mental and physical abnormalities, (iii) applying biofeedback to improve motor behavior, cognitive skills, and physical well-being.

Scientific fields:

The "Psychophysiology of Perception Lab" is active in the fields of visual perception, consciousness, attention, visual neuroscience, ophthalmology, motor coordination, pupillometry, (remote) photoplethysmography, cardiography, and behavior research.

Govermental institutes and commercial fields:

Our lab is also active in human recruitment, human resources, media, education, marketing, and health care.


We apply a large variety of methods, borrowed from many different disciplines, including quantitative psychophysics (reaction times and performance), qualitative questionnaires (IQ, etc.), gaze-tracking, pupillometry, heart rate (variability), ECG, food supplementation, EEG, TMS, and fMRI.


The material in the laboratory consists of multiple eye-trackers, industrial cameras, electroencephalograpy (EEG) setups, TMS setups, fMRI scanners (3-7T), and psychophysical settings.


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Marnix Naber

Head of laboratory

Google Scholar

Yun Ding

PhD student

Google Scholar

Brendan Portengen

PhD student


Roxana Alexandru

Master student


Rosemarijn Damen

Master student


Yongrui (Perseus) Zhao

Master student


International scientific collaborations:

Prof. George A. Alvarez (Vision Sciences Laboratory at Harvard University): expert on attention, working memory, and perception
Dr. Peter Murphy (Department of Neurophysiology at University Medical Center Hamburg): expert on pupillometry
Dr. Daniele Di Lernia (Università Cattolica del Sacro Cuore di Milano): expert on interoception
Dr. Jan Brascamp (Department of Psychology at Michigan State University): expert on eye-tracking and consciousness

National scientific collaborations:

Prof. Serge Dumoulin (Spinoza Centre for Neuroimaging): expert on fMRI and population receptive field mapping
Dr. Giorgio Porro (Ophthalmology of University Medical Center Utrecht): expert on diagnostics of cerebral visual impairments
Dr. Douwe Bergsma (Cognitive Neuroscience at Medical Center Nijmegen): expert on hemianopia
Prof. Mies van Genderen (Bartimeus Zeist): expert on visual impairments
Prof. Daan Scheepers (Leiden University): expert on psychophysiology

Local scientific collaborrations:

Prof. Stefan van der Stigchel: expert on attention, working memory, and perception
Prof. Maarten van de Smagt: expert on visual perception
Prof. Chris Dijkerman: expert on somatosensory perception
Dr. Teuni ten Brink: expert on unilateral spatial neglect
Dr. Christoph Strauch: expert on pupillometry
Dr. Nathan van der Stoep: expert on multisensory integration and eye-tracking
Dr. Sjoerd Stuit: expert on machine learning, emotions, and consciousness
Dr. Chris Paffen: expert on psychophysics and consciousness

Collaboration in industry:

Neurolytics: a HR company that uses psychophysiological measurements as biomarkers of motivation, interest, and stress
Holland Startup: a venture builder that supports startups
Bloakes: a marketing research company


Tijn Knaap

Master student


Mitchel Kappen

Master student


Felix Hermsen

External PhD student


Carlien Roelofzen

Master student


Joeri van Helden

Master student


Yentl de Kloe

Master student



Heart rate detection

HR(V) measurements with a webcam.


Eye-tracking in a large field stereoscope

Dichoptic eye tracking with one screen per eye.


Motion-induced blindness

An illusion used to study consciousness.

More info

Monocular rivalry

Illusion with two distinct percepts that alternate over time.



June-August 2018

BNR nieuwsradio - hartslag meten door de webcam:

Volkskrant Al te menselijke robots maken ons ongemakkelijk

RTV Utrecht We vinden menselijke robots eng en daarom zijn ze (nog) niet effectief

Universiteit Utrecht Nieuws Menselijke robot als griezelig ervaren

De utrechtste internet courant Onderzoeker UU: "Bijna menselijk is niet goed genoeg voor robots"

Numerikare Menselijke robot als griezelig ervaren

November 2013

Mare Rubriek Geklungel na-apen

Science Guide Na-apen belangrijker dan winnen

NWO Imiteren tegenstander onbewust belangrijker dan winnen

HoeZo? NTR Radio - Imiteren:

May 2013

In het 8 uur journaal - zon & de pupil:

HoeZo? NTR Radio - pupil reacties op plaatjes van de zon:


Volskrant Zon op foto verkleint pupillen ook

NU.NL Zon op foto verkleint pupillen ook

NWO Kijken naar een foto van de zon verkleint je pupillen ook

De morgen Zon op foto verkleint pupillen ook

Wetenschapsforum Kijken naar een foto van de zon verkleint je pupillen ook

Standaard Ook de zon op foto doet pupillen verkleinen

Scientias Pupil neemt het zekere voor het onzekere en verkleint bij foto van de zon

Het nieuwsblad Pupillen verkleinen door naar foto van de zon te kijken

RTL nieuws Pupil verkleint ook door zon op foto


For a full list of publications, see here

Most relevant publications:

Objectively assessing the content of consciousness
Naber, M., Fraessle, S., Einhaeuser, W. (2011). Perceptual Rivalry: Reflexes reveal the gradual nature of visual awareness. PLoS ONE
Fraessle, S., Sommer, J., Hansen, A., Naber, M., Einhäuser, W. (2014). Binocular Rivalry: Frontal activity relates to introspection and action, but not to perception. Journal of Neuroscience

Naber, M., Murphy, P. (2019). Pupillometric investigation into the speed‐accuracy trade‐off in a visuo‐motor aiming task. Psychophysiology
Naber, M., Alvarez, G.A., Nakayama, K. (2013). Tracking the allocation of attention using human pupillary oscillations. Frontiers in Psychology
Naber, M., Nakayama, K. (2013). Pupil responses to high-level image content. Journal of Vision
Naber, M., Fraessle, S., Rutishauser, U., Einhaeuser, W. (2013). Pupil size signals novelty and predicts later retrieval success for declarative memories of natural scenes. Journal of Vision

Remote photoplethysmography (webcam-based heart rate measurements)

Van der Kooij, K., Naber, M. (2019). An open-source remote heart rate imaging method with practical apparatus and algorithms. Behavior Research Methods

Imitation/Mimicry/Perception-action coupling

Naber, M., Vaziri Pashkam, M., Nakayama, K. (2013). Unintended imitation affects success in a competitive game. PNAS
Mathot, S., Naber, M. (2018). There is no evidence that pupil mimicry is a social phenomenon. PNAS
Derksen, M., van Alphen, J., Schaap, S., Mathot, S., Naber, M. (2018). Pupil Mimicry is the Result of Brightness Perception of the Iris and Pupil. Journal of Cognition