Daniel Joyce: Harmful and helpful lighting

Daniel Joyce


Harmful and Helpful Lighting


Daniel Joyce, Ph.D.



Bio sketch

Daniel Joyce is a research psychologist who works at the intersection of vision and circadian sciences. His research evaluates sensory deficits in non-image forming and perceptual vision and their role in color blindness, sleep-wake disorders and neurologic disorders. He uses this knowledge to develop both vision-based biomarkers to track disease and lighting technologies to counteract their symptoms and support wellbeing.

Project overview

Light is a fundamental driver of human behavior. Electric lighting coupled with societal pressures means that humans are now experiencing extremely different light exposure patterns than we have evolutionarily. We now spend about 90% of our daytime indoors under dim light while also viewing light emitting devices (e.g., TVs, cellphones) late into the night. The result is severe disruption to our sleep-wake rhythms, mood and cognition with negative repercussions for health and wellbeing.

This project focuses on inter-relations between environmental light exposures, how we sense and perceive light, and behavioral preferences. It will use a combination of wearable sleep sensors, tests of visual perception and cognitive tests to understand how individual differences regulate our light sensitivities. We hope to identify groups of people more vulnerable to dysregulation by aberrant light exposure patterns, and to develop light-based countermeasures that target the sensory pathways. Students have the opportunity to study in depth some combination of visual sensation, sleep and circadian rhythms, and mathematical modelling. Students may also pursue more independent lines of research related to visual sensation and perception or to sleep and circadian rhythms.