Sleep Need Outcompetes Preparation: Reframing Sleep Initiation Through Naturalistic Behavior
A new study published in SLEEP challenges conventional wisdom about what determines when humans actually fall asleep, arguing that the biological drive for sleep consistently overrides behavioral preparation.
Published online June 28, 2026, in the journal SLEEP, the article by Rhiannan H. Williams and Bastiaan Van der Veen of Boehringer Ingelheim Pharma’s Neuroscience and Mental Health division proposes a fundamental reframing of sleep initiation. Drawing on naturalistic behavioral observations rather than traditional laboratory paradigms, the authors contend that homeostatic sleep need, the physiological pressure to sleep that accumulates during wakefulness, ultimately outcompetes preparation-based approaches to initiating sleep.
The argument directly interrogates a long-standing assumption embedded in clinical sleep medicine and public health messaging: that pre-sleep routines, wind-down rituals, and sleep hygiene practices are primary determinants of how easily someone falls asleep. Williams and Van der Veen suggest that when homeostatic sleep drive is sufficiently high, it will override even poor preparation, and conversely, when sleep need is low, even the most disciplined behavioral routines cannot reliably force sleep onset.
This reframing carries significant implications for how insomnia is understood and treated. If the body’s biological drive for sleep is the dominant factor, interventions that focus primarily on behavioral rituals, such as stimulus control or relaxation techniques, may be addressing a secondary rather than a primary mechanism. The authors join a growing body of research re-centering the role of adenosine accumulation, circadian timing, and sleep-wake history as the core determinants of sleep initiation, with behavioral factors playing a modulating but not decisive role.
The study’s emphasis on naturalistic behavior marks a methodological departure worth noting. Most sleep research has relied on controlled laboratory environments where preparation and routine are artificially standardized. By observing sleep initiation in real-world conditions, Williams and Van der Veen argue, the relative contribution of homeostatic need versus behavioral preparation becomes clearer. This approach also captures variability in sleep drive across different settings and times that laboratory designs may mask.
The industry affiliation of the authors, Boehringer Ingelheim is a major pharmaceutical company active in neuroscience drug development, suggests that the paper may also carry implications for pharmacological approaches to sleep disorders. If sleep need is the bottleneck, interventions targeting the molecular pathways of homeostatic sleep regulation could hold more promise than behavioral modifications alone.
The full article is available in SLEEP, published by Oxford University Press.