What we are interested in

Our laboratory studies biologically based rhythms that are yearly, seasonal, monthly, and daily in length, including the circadian rhythm and the sleep-wake cycles. Our primary focus is to identify and characterize the effects of these rhythms on the variability of human cognition and performance.


In the Human Performance Rhythms Lab, we study the effects of biological rhythms on human performance, especially the near 24-hour circadian rhythm. We are particularly interested in the individual circadian differences known as Morningness-Eveningness or chronotype.

Morningness-Eveningness has a predominant genetic component that expresses itself in a person's preferences for daytime activities and sleep times. Some people prefer to be active early in the morning and go to bed early in the evening ('Larks') while others remain active late at night and sleep later into the morning ('Owls'). A majority of people, however, are primarily day-active ('Hummingbirds'). We use two Morningness-Eveningness questionnaires determine a person's chronotype: the Basic Language Morningness Scale (Brown, 1993) and the Morningness-Evenigness Questionnaire (Horne & Ostberg, 1976).