THE LIGHT CAFÉ · SCIENTIFIC BACKGROUND
The Light Café: a field study of morning light.
A planned adaptive field study of morning light exposure, circadian phase, sleep and cognition in Tübingen, Germany.
Study design01 / THE RESEARCH QUESTION
How does morning light
affect circadian timing?
How do light intensity and spectral composition shape the human circadian response in everyday settings?
The Light Café is a proposed field study combining controlled morning light exposure with circadian, behavioural and subjective outcome measures. It asks how responses vary across light conditions and between individuals.
A mobile research trailer, planned for the forecourt of Tübingen’s main railway station, will serve as both an intervention space and a meeting place for researchers and the public.
The long-term aim is to inform biologically grounded, more personalised light interventions. These are research objectives, not established outcomes of this project.
02 / PLANNED STUDY DESIGN
The study
at a glance.
Sequential cohorts with light conditions
adapted in response to previous observations.
per participant
over two weeks
across 6–8 cohorts
- BASELINE
Baseline
measurementsAssess circadian phase with dim-light melatonin onset (DLMO), alongside actigraphy and cognitive performance measures.
- INTERVENTION
Morning light
sessionsTen one-hour sessions on weekdays, within four daily time windows between 07:00 and 11:00. Light intensity and spectral composition are controlled.
- FOLLOW-UP
Repeat assessments
and analyse the data.Repeat the assessments and collect subjective tiredness and well-being measures. Analyse each cohort to inform subsequent light conditions.
Up to six participants per time window and up to 24 per cohort are planned. The sample range is an operational recruitment estimate in the project proposal, not a reported power calculation. Exact light settings, eligibility criteria, allocation procedures and adaptation rules are not yet specified here.
03 / OUTCOME DOMAINS
What we plan
to measure.
Circadian, behavioural
and subjective measures.
- Circadian phase DLMO
- Timing of the evening rise in melatonin under dim-light conditions, measured before and after the intervention.
- Sleep and activity ACTIGRAPHY
- Objective assessment of rest–activity patterns using a wearable sensor.
- Cognition PERFORMANCE
- Tasks assessing cognitive performance and attention alongside the physiological measurements.
- Daily experience SELF-REPORT
- Subjective tiredness and well-being following the intervention.
Research and
public engagement
The trailer will also host conversations and short talks about light and circadian rhythms.
These activities are intended for the wider public as well as study participants. The mobile infrastructure builds on the “Nachtmensch oder Frühaufsteher?” science roadshow.
Planned outputs include methodological work on adaptive field interventions and empirical analyses of how light conditions relate to circadian, sleep and cognitive outcomes.
Explore the science roadshow04 / TEAM & SCIENTIFIC CONTACT
Study team
tSCN Lab Prof. Dr. Manuel Spitschan
Scientific lead · Translational Sensory and Circadian Neuroscience
Max Planck Institute for Biological Cybernetics, Tübingen
SCIENTIFIC ENQUIRIES
Scientific
contact
For questions about the study concept or potential scientific collaboration, contact the scientific lead.
Contact Manuel SpitschanInterested in taking part? Visit the German project page.